Acid Rain and Transported Air Pollutants: Implications for Public Policy

Acid Rain and Transported Air Pollutants:Implications for Public Policy

May 1984

NTIS order #PB84-222967

Recommended Citation:Acid Rain and Transported Air Pollutants: Implications for Public Policy (Washington, D. C.:U.S. Congress, Office of Technology Assessment, OTA-O-204, June 1984).

Library of Congress Catalog Card Number 84-601073

For sale by the Superintendent of DocumentsU.S. Government Printing Office, Washington, D.C. 20402

Foreword

Transported air pollutants have been the topic of much debate during the Clean Air Act delibera-tions of the 97th and 98th Congresses. The current controversy over acid rain—the most publicizedexample of transported pollutants—focuses on the risks to our environment and ourselves versusthe costs of cleanup. Since 1980, the committees responsible for reauthorizing the Clean Air Act—theHouse Committee on Energy and Commerce and the Senate Committee on Environment and PublicWorks—have called on OTA many times for information about the movements, fate, and effectsof airborne pollutants, the risks that these transported air pollutants pose to sensitive resources,and the likely costs of various proposals to control them. Over the course of the debate, OTA hasprovided extensive testimony and staff memoranda to the requesting committees, and publisheda two-volume technical analysis, The Regional Implications of Transported Air Pollutants, in July1982. This report synthesizes OTA’s technical analyses of acid rain and other transported pollut-ants, and presents policy alternatives for congressional consideration.

OTA’s work over the last several years has enabled us to forecast with reasonable accuracy thecost of controlling pollutant emissions, and, for each of the many pending legislative proposals,who will pay those costs. We also know a great deal about the transport, fate, and effects of t rans -ported air pollutants—vastly more than was known several years ago when Congress last consid-ered the Clean Air Act. Still, it is not yet possible to accurately evaluate the damages wroughtby the pollutants or the benefits to be gained by reducing emissions, though we can say that boththe risks of harm and the costs of control are substantial.

The issue of transported pollutants poses a special problem for policy makers: assuring regionalequity while balancing concerns for economic well-being with concerns for natural and humanresources across large regions of the Nation. Scientific uncertainties surrounding many aspects ofthe problem complicate the decision of whether, or when, to control transported air pollutants.Additional complexities arise from our inability to treat costs, damages, and benefits in a uniform,quantitative way. Moreover, in OTA’s judgment, even substantial additional scientific researchis unlikely to provide significant, near-term policy guidance, or resolve value conflicts.

How, then, can Congress address current damage, consider potential harm to recipients of trans-ported air pollutants, yet not enforce an unnecessarily high cost on those who would be requiredto reduce pollutant emissions? OTA’s analysis cannot provide an unambiguous answer to thisdilemma. It does, however, lay out some carefully weighed estimates of costs, some carefully rea-soned conclusions about the nature and extent of downwind damages and risks, and several policyoptions that merit consideration. We hope that this information will help to narrow the issues ofcontention for this important environmental concern.

OTA is grateful for the assistance of the advisory panel, contractors, and the over 200 reviewerswho provided advice and information throughout the course of this assessment.

Director

,..Ill

Transported Air Pollutants Advisory Panel

Norton Nelson, ChairmanNew York University Medical Center

Thomas H. Brand Gene E. LikensEdison Electric Institute Cornell University

Robert Wilbur Brocksen Anne LaBastilleElectric Power Research Institute Adirondack Park Agency

Jack George Calvert Donald H. PackNational Center for Atmospheric Research Private Consultant

David Hawkins Carl ShyNational Resources Defense Council, Inc. University of North Carolina

Edward A. Helme George H. Tomlinson, IINational Governors’ Association Domtar, Inc.

Richard L. KerchConsolidation Coal

Principal Contractors

Brookhaven National LaboratoryKathleen Cole, Duane Chapman,

Clifford RossiEnergy & Resource ConsultantsEnvironmental Law InstituteBarbara J. Finalyson-Pitts,

James N. Pitts, Jr.

Additional Contributors

A. S. L. & AssociatesSanford BergDaniel BromleyThomas CrockerEnergy & Environmental Analysis, Inc.Yacov HaimesPerry HagensteinDavid HarrisonWalter HeckIR & T Corp.

Brand L. NiemannOak Ridge National LaboratoryE. H. Pechan & AssociatesPerry J. SampsonJack ShannonThe Institute of Ecology

Steven OlsonJames ReaganLarry SalatheJohn P. SkellySRI InternationalTRC Environmental ConsultantsMichael P. Walsh

OTA Proiect Staff—Transported Air Pollutants Assessment

John Andelin,Science, Information,

Assistant Director, OTAand Natural Resources Division

Robert W. Niblock, Oceans and Environment Program Manager

Robert M. Friedman, Project Director

Rosina M. Bierbaum, Assistant Project Director

Patricia A. Catherwood, Research Analyst

Stuart C. Diamond, * Editor/Writer

George C. Hoberg, Jr., * Polic y Analyst

Valerie Ann Lee, Policy Analyst

Contributing Staff

Linda Garcia Iris Goodman Nancy Greenbaum Jennifer N. Marsh

Administrative Staff

Kathleen A. Beil Jacquelynne R. Mulder Kay Senn

Contents

Chapter

1.

2.

3.

4.

5.

6.

7.

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. ... . $....”...

The Policy Dilemma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ......”””.

Transported Air Pollutants: The Risks of Damage and the Risks of Control.

The Pollutants of concern . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

The Regional Distribution of Risks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Policy Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... $.. ....”

Legislating Emissions Reductions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Appendix

A. Emissions and the Costs of Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

B. Effects of Transported Pollutants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

C. Atmospheric Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . - . ’ ’ . . ..-’’”.-. .’.

D. Existing Domestic and International Approaches . . . . . . . . . . . . . . . . . . . . . . . . .

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .”.

Page

3

27

41

57

79

103

121

Page

149

207

265

300321

Photo credit: MESOMET, Inc.

A hazy, polluted air mass is outlined on this July 1978 enhanced satellite photo. High levels of airborne sulfate andozone, along with low visibility, persisted for about a week over much of the Eastern United States and Canada. Thepolluted air mass extends far offshore— at least 500 miles from manmade emissions sources—visible evidence of long-

distance transport of air pollution.

Chapter 1

Summary

Contents

PageThe Pollutants of Concern . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

The Risks From Transported Air Pollutants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

The Risks of Controlling Transported Air Pollutants . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Policy Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

FIGURES

Figure No. PageI. Transported Air Pollutants: Emissions to Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42. Precipitation Acidity—Annual Average pH for 1980 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63. Ozone Concentration—Daytime Average for Summer 1978 . . . . . . . . . . . . . . . . . . . . . . . . . 74. Sulfur Dioxide and Nitrogen Oxides Emissions—State Totals for 1980 . . . . . . . . . . . . . . . 75. Sulfur Dioxide and Nitrogen Oxides Emissions Trends—National Totals, 1900-2030 . . . 86. Average Sulfur Transport Distances Across Eastern North America . . . . . . . . . . . . . . . . . . 97. Regions of the Eastern United States With Surface Waters Sensitive

to Acid Deposition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108. Recent Forest Productivity Declines Throughout the Eastern United States. . . . . . . . . . . . 119. Cost of Reducing Sulfur Dioxide Emissions by 10 Million Tons per Year,

Nationwide Increases in Annual-Average Electricity Bills fora Typical Residential Consumer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Chapter 1

Summary

Until recently, air pollution was considered alocal problem. Now it is known that winds can carryair pollutants hundreds of miles from their pointsof origin. These transported air pollutants can dam-age aquatic ecosystems, crops, and manmade ma-terials, and pose risks to forests and even to humanhealth. Throughout this report we discuss three ofthese pollutants: acid deposition (commonly calledacid rain), atmospheric ozone, and airborne fineparticles.

The Clean Air Act—the major piece of Federallegislation governing air quality in the UnitedStates—addresses local air pollution problems butdoes not directly apply to pollutants that travelmany miles from their sources. However, reportsof natural resource damage in this country, Can-ada, Scandinavia, and West Germany have madetransported air pollutants—particularly acid rain—a focus of scientific and political controversy. Manyindividuals and groups, pointing to the risk of ir-reversible damage to resources, are calling for morestringent Federal pollution controls. Others, em-phasizing scientific uncertainties about transportedair pollutants and drawing different conclusionsabout how to balance risks against costs, contendthat further pollution controls are premature, maywaste money, and would impose unreasonable bur-dens on industry and the public.

OTA’s analysis of acid deposition and othertransported air pollutants concludes that thesesubstances pose substantial risks to Americanresources. Thousands of lakes and tens of thou-sands of stream miles in the Eastern United Statesand Canada are vulnerable to the effects of aciddeposition. Some of these have already beenharmed. Elevated levels of atmospheric ozone havereduced crop yields on American farms by hun-dreds of millions of bushels each year. Acid depo-sition may be adversely affecting a significant frac-tion of Eastern U.S. forests; it, along with suchother stresses as ozone and natural factors such asdrought, may account for declining forest produc-tivity observed in parts of the East. Both sulfuroxides and ozone can damage a wide range of man-made materials. Airborne fine particles such as

sulfate reduce visibility and have been linked to in-creased human mortality in regions with elevatedlevels of air pollution.

The costs of reducing pollutant emissions arelikewise substantial. Most current legislative pro-posals to control acid deposition would cost about$3 billion to $6 billion per year. Adding these newemissions control proposals to our Nations currentenvironmental laws would increase the total costsof environmental regulation by about 5 to 10 per-cent. Average electricity costs would rise by sev-eral percent— as high as 10 to 15 percent in a fewMidwestern States under the most stringent pro-posals. Additional emissions controls could alsohave important indirect effects, such as job disloca-tions among coal miners and financial burdens onsome utilities and electricity-intensive industries.

Any program to reduce emissions significantlywould require about 7 to 10 years to implement.If no further action is taken to control emissions,30 to 45 years will elapse before most existing pol-lution sources are retired and replaced with facil-ities more stringently regulated by the Clean AirAct. The effective time frame of most proposalsto control acid deposition, therefore, is the in-tervening period of about 20 to 40 years—longenough to be significant to natural ecosystems.

If all the risks posed by transported air pollut-ants were realized over this time period, resultingresource damage would outweigh control costs. Therisks discussed throughout this report, however, arepotential consequences, not necessarily the conse-quences that will, in fact, occur.

One of the most difficult questions facing Con-gress, therefore , is whether to act now to con-trol acid deposition or wait for results from ongo-ing multimillion-dollar research programs. Bothinvolve risks. Delaying action for 5 or 10 years willallow emissions to remain high for at least a decadeor two, with the risk of further ecological damage.But predicting the magnitude and geographic ex-tent of additional resource damage while waitingis not possible. Acting now involves the risk thatthe control program will be less cost effective or ef-

3

4 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

ficient than one designed 5 or 10 years from now. The policy decision to controlSignificant advances in scientific understanding transported air pollutants mustover this time period, however, are by no means risks of resource damage, the

or not to controlbe based on therisks of unwar-

assured. -

The distributional aspects of transported airpollutants further complicate the congressionaldilemma. Because these pollutants cross State andeven international boundaries, they can harm re-gions far downwind of those benefiting from theactivities that produce pollution. Moreover, dif-ferent economic sectors bear the risks of waiting

ranted control expenditures, and the distribu-tion of these risks among different groups andregions of the country. This study describes thetradeoffs implicit in this choice by characterizingthe extent of the risks, their regional distribution,and the economic sectors that bear them. It con-cludes with a list of policy options available to Con-gress for addressing transported air pollutants.

or acting now to control.

THE POLLUTANTS OF CONCERN

The transported air pollutants considered in this sulfate and nitrate. Acid deposition results whenstudy result from the emission of three primary pol- sulfur and nitrogen oxides and their transforma-lutants: sulfur dioxide, nitrogen oxides, and tion products return from the atmosphere to thehydrocarbons. As these pollutants are carried away Earth’s surface. Elevated levels of ozone arefrom their sources, they can be transformed through produced through the chemical interaction of ni-complex chemical processes into secondary pollut- trogen oxides and hydrocarbons (see fig. 1). Nu-ants: ozone and airborne fine particles such as merous chemical reactions—not all of which are

Figure 1 .—Transported Air Pollutants: Emissions to EffectsThe transported air pollutants considered in this study result from emissions of three pollutants: sulfur dioxide, nitrogen oxides,and hydrocarbons. As these pollutants are carried away from their sources, they form a complex “pollutant mix” leading toacid deposition, ozone, and airborne fine particles. These transported air pollutants pose risks to surface waters, forests, crops,materials, visibility, and human health.

Ch. l—Summary ● 5

completely understood—and prevailing weatherpatterns affect the overall distribution of acid depo-sition and ozone concentrations.

Current levels of precipitation acidity and ozoneconcentrations are shown in figures 2 and 3, re-spectively. Peak levels of acid deposition—as meas-ured by precipitation acidity, or pH*—centeraround Ohio, West Virginia, and western Penn-sylvania. High levels of acid deposition are foundthroughout the United States and southeasternCanada. Peak values for ozone are found furthersouth than for acid deposition, centering aroundthe Carolinas. A band of elevated ozone concen-trations extends from the mid-Great Plains Statesto the east coast.

During 1980 some 27 million tons of sulfurdioxide and 21 million tons of nitrogen oxideswere emitted in the United States. Figure 4displays the regional pattern of emissions. About80 percent of the sulfur dioxide and 65 percent ofthe nitrogen oxides came from within the 31 Statesbordering or east of the Mississippi River. Figure5 shows how these emissions have varied since 1900.Since 1940, sulfur dioxide emissions increased byabout 50 percent and nitrogen oxides emissionsabout tripled. Throughout the same period, talleremission stacks became common, allowing pollut-ants to travel farther.

Figure 5 also shows a range of projected futureemissions of these pollutants, assuming that cur-rent air pollution laws and regulations remain un-changed. Actual future emissions will depend onsuch factors as the demand for energy, the type ofenergy used, and the rate at which existing sourcesof pollution are replaced by newer, cleaner facil-ities. By 2030—the end of the projection period—most existing facilities will have been retired. De-spite relatively strict pollution controls mandatedfor new sources by the Clean Air Act, emissionsof both sulfur and nitrogen oxides are likely toremain high for at least the next half century.

The pollutants responsible for acid deposition canreturn to Earth in rain, snow, fog, or dew—col-

*Acidity is measured in pH units, Decreasing pH corresponds toincreasing acicidity, but in a nonlinear (logarithmic) way. Across theUnited States, average annual rainfall pH varies between about 4 and6. Compared to a pH of 6, pH 5 is 10 times more acidic; pH 4 is100 times more acidic; and so on. Referring to the shading in figure2, pH 4.2 is twice as acidic as pH 4.5; about 6 times more acidic thanpH 5; and about 20 times more acidic than pH 5.5.

lectively known as acid precipitation—or as dryparticles and gases. Averaged over the EasternUnited States, about equal amounts of sulfurcompounds are deposited in wet and dry forms.However, in areas remote from pollution sources,such as the Adirondacks, wet deposition may ac-count for up to 80 percent of the sulfur deposited;in urban areas near many sources of pollution thesituation is reversed. 1

Pollutants emitted into the atmosphere can re-turn to Earth almost immediately or remain aloftfor longer than a week, depending on weather pat-terns and the pollutants’ chemical interactions.During this time they move with prevailing winds,which in the Eastern United States tend to movefrom west to east and from south to north.

Preliminary analyses suggest that about one-third of the total amount of sulfur compoundsdeposited over the Eastern United States as awhole originates from sources over 500 kilome-ters (km) (300 miles) away from the region inwhich they are deposited. Another one-thirdcomes from sources between 200 and 500 km ( 120to 300 miles) away, and the remaining one-thirdcomes from sources within 200 km ( 120 miles).2

Because pollution sources are unevenly distrib-uted across the Eastern United States and Canada,the relative contribution of emissions from local,midrange, and distant sources varies by region. Asshown in figure 6, sulfur deposition in the Mid-west— a region with high emissions—is dominatedby emissions from sources within 300 km (180miles). The sulfur compounds that reach the less-industrialized New England region typically havetraveled farther. The ‘ ‘average’ distance—consid-ering the contribution from both local and distantsources—is about 500 to 1,000 km (300 to 600 miles).

] E. Altwicker and A. Johann es, ‘ ‘Wet and Dry Deposition inAdirondack Watersheds, The Integrated Lake- ~1’atershcd Acidifica-tion Study: Proceedings of the IL WAS Annual Rc’ticw Conference,Electric Power Research Institute, EPRI EA-2827, 1983: andD. Fowler, ‘‘ Removal of Sulfur and Nitrogen C;ornpounds From theAtmosphere, Ecolo<qi(al Irnpar-t of’ Acid Precipitation, SNSF Proj-ect, Norwa>, 1980.

‘J. Shannon, ‘ ‘Estimation of North American Anthropogenic SulfurDeposition as a Function of Source-Receptor Separation, paper pre-sr.-nteci at the NA TO 14th In ternationaf Technical AfeetinLg on ,4ir~~o]][ltlon ,$f(~clinq amf Its Application, Copenhagen, 19~:~.


/“

Figure 2.–Precipitation Acidity–Annual Average for 1980

Legend:

Ch. l—Summary ● 7

Figure 3.–Ozone Concentration–Daytime Average for Summer 1978

Figure 4.—Sulfur Dioxide and Nitrogen Oxides Emissions—State Totals for 1980

8 . Acid Rain and Transported Air Pollutants: Implications for Public Policy

34

Ch. 1—Summary 9

Figure 6.-Average Sulfur Transport Distances Across Eastern North America

THE RISKS FROM TRANSPORTED AIR POLLUTANTS

The best documented and best understood ef-fects of acid deposition are those on aquatic eco-systems. The sensitivity of a lake or stream to aciddeposition depends largely on the ability of the soiland bedrock in the surrounding watershed to neu-tralize acid. Where the soil is very thin or has littleneutralizing capacity, or where the terrain is sosteep or rocky that rainfall runs right over it, thebodies of water within a watershed are at risk.When the waters of a lake or stream become more

acidic than about pH 5, many species of fish dieand the ecosystem changes dramatically. This maybe due to the acidity, to the metals (especially alu-minum) released under acidic conditions, or to acombination of both.

By categorizing the predominant soil and geo-logical characteristics in each county of the East-ern United States, this study estimates the poten-tial number of lakes and streams at risk from acid


deposition. Because of the uncertainties involved,these numbers should be viewed as qualitative es-timates only. In the 31 States bordering and eastof the Mississippi River, roughly 25 percent of the

Figure 7.—Regions of the Eastern

land area contains soils and bedrock that allow acid-ity to travel through a watershed to lakes andstreams (see fig. 7). About 17,000 lakes and 112,000miles of streams lie within these sensitive areas. As

United States With Surface WatersSensitive to Acid Deposition

The regions shaded light grey contain soils and bedrock that allow acidity to travel througha watershed to lakes and streams. Due to local variations, however, not all water bodies withinthese areas are sensitive to acid deposition. Likewise, some sensitive water bodies may belocated outside the light grey areas. The dark areas contain lakes and streams that currentlyhave such limited ability to neutralize acida (as measured by water quality surveys) that theyare now extremely vulnerable to further acid deposition or are already acidic.

aRegions with surface waters that have mean annual alkalinity less than 100 microequivalents per liter.SOURCES: Off Ice of Technology Assessment. Composite map from the Institute of Ecology, “Regional Assessment of Aquatic

Resources at Risk From Acid Deposition,” OTA contractor report, 1982; and J. Omernik, “Total Alkalinity of Sur-face Water,” draft map prepared for the U.S. Environmental Protection Agency, 1983.

Ch. 1—Summary ● 11

a “best guess, ” about half of these lakes andstreams have such limited ability to neutralize acidthat they will acidify if enough acid-producing pol-lutants are deposited. We estimate that about3,000 lakes and 23,000 miles of streams—orabout 20 percent of those in the sensitive areas—are now extremely vulnerable to further aciddeposition or have already become acidic. NewEngland has the greatest percentage of lakes andstreams considered sensitive to acid deposition. TheUpper Midwest also has large numbers of sensitive

lakes, and many sensitive streams are found in theCentral Appalachian region.

In addition to the acidification of aquatic ecosys-tems, transported air pollutants have been linkedto harmful effects to terrestrial ecosystems. Broadforested areas subjected to elevated levels of aciddeposition, ozone, or both have been marked bydeclining productivity and dying trees, althoughit is uncertain how much of this is due to air-borne pollutants. Figure 8 documents significant

Figure 8.— Recent Forest Productivity Declines Throughout the Eastern United States

The photograph shows corings from three softwood tree species growing on six sites across the East from Vermont to Tennessee.The corings show normal growth-widely spaced tree rings —until about 1960 (marked with a stripe). From about 1960 to thepresent the tree rings have markedly narrowed, evidence of decreased growth. Concerns have been raised that elevated levelsof ozone and acid deposition in these regions may be involved in the observed declining productivity. As of now, the causeis unexplained.

SOURCE Arthur Johnson, University of Pennsylvania Samuel McLaughlin, Oak Ridge National Laboratory

72 ● Acid Rain and Transported Air Pollutants: lmplications for Public Policy

growth declines in several tree species beginningabout 1960 throughout the East from Vermont toTennessee. Acid deposition, ozone, heavy-metaldeposition, drought, severe winters, or a combina-tion of these stresses are possible causes under in-vestigation.

Acid deposition might be harming trees in twoways: either directly (e. g., by removing nutrientsfrom leaves), or indirectly, by altering the soils onwhich trees grow. If acid deposition harms treesdirectly, much of the forested area of the EasternUnited States is at risk, with the greatest risk inhigh elevation areas where deposition is often great-est. If acid deposition affects forest soils, forestsgrowing on nutrient-poor, naturally acidic soils areof greatest concern. This study estimates that suchsoils cover about 15 to 20 percent of the land areaof the Eastern United States, primarily parts of NewEngland, the Upper Midwest, and the South. Aciddeposition might be stripping such essential nutri-ents as calcium and magnesium from these soils,or releasing metals, such as aluminum, that aretoxic to plants. Whether this nutrient loss or re-lease of metals from the soil is large enough to af-fect forest productivity at current levels of aciddeposition is unknown.

A large area of U.S. forests is also exposed toelevated ozone concentrations. Ozone has beenshown to damage tree foliage and reduce the growthrates of certain sensitive tree species. But itscumulative effect on forest productivity over thelifetime of trees—half a century or more—is diffi-cult to predict.

Transported air pollutants adversely affect agri-cultural productivity. Up to 90 percent of the dam-age to crops from air pollutants may be due toozone. Large areas of the United States, includingmuch of the Midwestern Corn and Soybean Belts,are exposed to high levels of ozone. This study esti-mates that if ozone levels were reduced to their nat-ural background levels, corn yields would have been2 percent higher, wheat yields 5 percent higher, soy-bean yields 13 percent higher, and peanut yields24 percent higher. Based on the value of thesecrops, ozone causes about a 6- to 7-percent lossof U.S. agricultural productivity.

Many areas of abundant agricultural production,such as Illinois, Indiana, and Ohio, also receive

high levels of acid deposition. Some experimentsusing simulated acid rain have demonstrated re-duced yields of agricultural crops, but others havefound no effect.

Airborne pollutants accelerate the deteriora-tion of many economically important materials.Sulfur oxides damage iron and steel, zinc, paint,and stone; certain types of rubber are susceptibleto ozone. Pollution-induced damage is difficult toquantify because it cannot be distinguished readilyfrom the weathering effects of the natural environ-ment. The bulk of materials damage is thought tobe caused by pollutants emitted locally. Regionsat greatest risk are urban areas (especially those inindustrial regions) and areas with historicallysignificant buildings and monuments. One recentstudy estimated that reducing sulfur dioxide emis-sions in selected urban areas to achieve concentra-tions 25 to 30 percent below the current air qualitystandard could yield materials-related benefits ofhundreds of millions of dollars annually.3 Pollut-ant effects on unique or historic structures may beirreparable, and thus cannot be evaluated solely inmonetary terms.

Air pollutants—along with natural causes suchas humidity, fog, and dust—can significantly im-pair visibility. They reduce contrast, discolor theatmosphere, and obscure distant objects. In theEastern United States, airborne sulfates appearto be the single greatest contributor to reducedvisibility, causing about 50 percent of visibil-ity impairment annually, and about 70 percentduring the summer.4 In the West, windblown dustand nitrogen oxides can also impair visibility sig-nificantly.

Air concentrations of sulfur dioxide, nitrogen ox-ides, and ozone are currently regulated to protecthuman health. No standards exist for airbornesulfates, which may also pose a threat to humanhealth. At high exposure levels, sulfates can ag-

3E. H. Manuel, Jr., et al., “Benefits Analysis of Alternative Sec-ondary National Ambient Air Quality Standards for Sulfur Dioxideand Total Suspended Particulate, Mathtech, Inc., report submittedto the U.S. Environmental Protection Agency, OAQPS, 1982.

‘For example, see M. Ferman, et al., ‘ ‘The Nature and Source ofHaze in the Shenandoah Valley/Blue Ridge Mountain Area, ‘J. AirPollution Control Assoc. 31: 1074-1082, 1981; and U.S. EnvironmentalProtection Agency, Protecting Visibility, An EPA Report to Congress,EPA 450/5-79-008, 1979.

Ch. l—Summary 13

gravate existing heart and lung conditions such asasthma. Several statistical studies comparing his-torical air pollution data and health records founda correlation between airborne sulfate levels andmortality, but whether there is a causal link betweenthe two is not clear. For instance, elevated sulfatelevels often occur with other airborne fine particles,one or more of which might be causing harm.

Disagreement exists within the scientific commu-nity over the significance of airborne sulfates tohuman health. Some researchers conclude thatthere is a negligible effect at prevailing concen-trations; others have found a significant asso-ciation—several percent of annual mortality,primarily among people with preexisting cardiacor respiratory problems. By combining the vari-ous estimates, this study concludes that a reason-able estimate of the magnitude of health risk posedby current levels of sulfates and other particulate

is about 50,000 premature deaths (2 percent of totaldeaths) per year in the United States and Canada.This estimated health risk from transported air pol-lutants is a measure of possible harm. It can nei-ther be confirmed nor disproven until further re-search is conducted.

Acidified waters can dissolve metals and toxicsubstances from soils, rocks, conduits, and pipes,and subsequently transport them into drinking wa-ter systems. Municipal water supplies can bemonitored and corrected quite easily; potentialproblems with well water in rural areas are moredifficult to detect and mitigate. Although acid depo-sition has not been proven to be the cause, watersamples from a few areas in the Adirondacks andNew England receiving high levels of acidity havecontained lead concentrations exceeding the health-based standards.

THE RISKS OF CONTROLLINGTRANSPORTED AIR POLLUTANTS

The above discussion of the risks from trans-ported air pollutants relies heavily on such wordsas ‘ ‘could’ and ‘ ‘might’ because at present, wecan only make educated guesses about the scopeand severity of the problem. For example, scien-tists are certain that acid deposition damages lakesand streams, and that ozone damages crops. Butthey cannot say with certainty how many lakes andstreams and what quantity of crops have beendamaged. Nor can they forecast with confidencewhat these damages will be in the future. Part ofthe difficulty is the uncertainty about the extent towhich resource damage is cumulative—some typesof resource damage might worsen even if levels ofacid deposition remain about the same.

These uncertainties are compounded by impre-cise knowledge of the transport and transformationof pollutants emitted throughout the Eastern UnitedStates and Canada. Scientists have devised atmos-pheric transport models to simulate the movementof sulfur emissions. But even with these sophis-ticated tools, scientists can only estimate the amountof sulfur pollution transported from one large re-

gion to another, over seasonal to annual time scales.Similarly, scientists cannot confidently predict thedegree to which emissions reductions in one regionwould reduce deposition in another.

Intertwined with the scientific uncertainties aboutthe benefits of a control program are disagreementsover values. Few would deny that there are signif-icant environmental risks associated with trans-ported air pollutants. But there are also risks asso-ciated with controlling these pollutants—therisks that the benefits from reducing emissionsdo not justify the economic and social costs.

Various groups and individuals differ sharply onwhere the balance should be struck between pro-tecting the environment and protecting other areasof economic well-being. There is little agreementon the intrinsic worth of resources or the equitabledistribution of costs to protect those resources. Un-fortunately, more accurate atmospheric transportmodels or a better understanding of the level ofemissions required to protect sensitive resources willdo little to solve such questions of values.


To put the risks and uncertainties of controllingtransported air pollutants into context, this studyexamines a range of programs to reduce emissions,focusing on the direct and indirect costs for spe-cific regions of the United States and the countryas a whole.

Most of the proposals introduced during recentsessions of Congress would control sulfur dioxideemissions, since sulfur compounds contribute twiceas much acidity to rainfall in the Eastern UnitedStates as nitrogen compounds and are morestrongly implicated with a variety of adverse effects.This study estimates that the annual costs to re-duce sulfur dioxide emissions in the 31 Statesbordering and east of the Mississippi River couldrange from about $1 billion (or less) for about a10- to 20-percent reduction, to about $3 billion to$6 billion for a 35- to 45-percent reduction below1980 emissions levels by 1995.

The larger control programs could have sever-al significant consequences. The average cost ofelectricity will increase by several percent. Cer-tain utilities and electricity-intensive industriesmight be financially strained. And, if utilitiesachieve emissions reductions in part by switch-ing to low-sulfur coal, jobs would be displacedfrom areas where coal high in sulfur content ismined to areas producing low-sulfur coal.

Because electric utilities account for about three-fourths of the sulfur dioxide emitted in the East-ern United States, most current legislative proposalswould require significant reductions in utility emis-sions. In particular, utilities in the MidwesternStates, which tend to burn high-sulfur coal, wouldbear the greatest impact of an emissions control pro-gram. Ultimately, these costs would be passed onto consumers in the form of higher utility bills. Forexample, this study estimates that 10 million tonsof sulfur dioxide emissions could be eliminatedfrom existing sources nationwide for about $3billion to $4 billion per year, increasing aver-age electricity rates by 2 to 3 percent. These rateincreases would vary by State, as shown in figure9. Consumers in some States would see no in-

creases, while others would pay increases over threetimes the national average. If the projected futuregrowth in emissions must also be offset throughreductions from current emitters (an additional1 million to 3 million tons per year by 2000),average residential electricity costs could rise byabout 4 to 5 percent, with increases of 10 to 15percent in several States.

An emissions control program could strain thefinancial resources of a number of electric utilities,particularly if State regulatory policies prohibitthem from quickly passing on control costs to con-sumers. Based on selected economic ratings and therange of current State policies, utility sectors in sev-eral States might be relatively vulnerable to the ad-ditional capital requirements for pollution controlequipment. Few of the States with the highestpercentages of economically vulnerable utilities,however, are allocated extensive emissions reduc-tions under current acid rain proposals.

Some firms and industries that rely heavily onelectricity could become less competitive if theirelectricity rates were to increase substantially aboverates in other parts of the country. Of greatest con-cern are those that produce electrometallurgicalproducts, zinc and aluminum, alkali- and chlorine-based chemicals, and industrial gases.

If a control program is enacted that allows eachutility to freely choose its own method of achiev-ing emissions reductions, some utilities will chooseto switch from burning high-sulfur coal to low-sulfur coal. Under such a ‘freedom-of-choice’program to eliminate 10 million tons of emis-sions per year, future levels of high-sulfur coalproduction could fall 10 to 20 percent below1980 levels. Employment in regions that minehigh-sulfur coal could be 20,000 to 30,000 jobsbelow projected levels. An equivalent number ofjobs would open up in Eastern and Western Statesthat mine low-sulfur coal. Legislation that man-dates the use of high-removal control technologycould minimize such dislocations, but could in-crease total program costs by about $1.5 billionper year.

Ch. l—Summary ● 1 5

Figure 9.—Cost of Reducing Sulfur Dioxide Emissions by 10 Million Tons per Year,Nationwide Increases in Annual-Average Electricity Bills for a Typical Residential Consumer

A n

I

‘Average annual cost increase (1982 dollars) for a typical residence consuming 750 kWh/month electricity Percentage rate Increases in each State are calculated ‘rem

State. average 1982 electricity costs (ranging from about $200 to $900/yr, United States average about $600/yr)

SOURCE’ Office of Technology Assessment, based on analyses by E. H. Pechan & Associates, Inc.

POLICY OPTIONS

Four approaches for congressional action on aciddeposition and other transported air pollutants arediscussed below:

A. Mandating emissions reductions to furthercontrol the sources of transported pollutants.

B. Liming lakes and streams to mitigate someof the effects of acid deposition.

c.

D.

Modifying the Federal acid deposition re-search program to provide more timely gui-dance for congressional decisions.Modifying existing sections of the Clean AirAct to enable the Environmental ProtectionAgency, States, and countries to more effec-tively address transported air pollutants otherthan acid deposition.

16 ● Acid Rain and Transported Air Pollutants: Implication for Public Policy

Congress could choose to adopt some or all of theseapproaches in its consideration of clean air legisla-tion. A comprehensive strategy to address trans-ported air pollutants might well include optionsfrom all four of the approaches discussed below.

Approach A:

Discussion

Mandating Emissions ReductionsTo Further Control the Sources ofTransported Pollutants.

Legislated emissions reductions could range frommodest reductions to keep emissions at—or some-what below—current levels, to large-scale controlprograms. In choosing an appropriate program,Congress will need to weigh the risks of potentialresource damage, the risks of inefficient control ex-penditures, and the distribution of these risksamong different groups and regions of the country.

Mandating further emissions reductions wouldrequire Congress to make a number of interrelatedchoices. These include decisions about which pol-lutant emissions to reduce, from what regions, byhow much, and over what time period. Congresswould also need to choose specific policy mecha-nisms to implement the reductions, allocate theircosts, and address undesired secondary conse-quences of emissions reductions.

This study has divided these decisions into eightdistinct questions, which can be answered in dif-ferent ways to produce different control programs.Three representative control programs are pre-sented at the end of the discussion of this approach.

● Which Pollutants Should Be FurtherControlled?

In the East, sulfur compounds currently contrib-ute about twice as much acidity to precipitation asnitrogen compounds. Moreover, throughout thegrowing season, plants use much of the depositednitrogen as a nutrient, making sulfur compoundsresponsible for a still larger share of acidity reachinglakes and streams. Sulfur compounds damage ma-terials and in the particulate form (sulfate) reducevisibility and pose risks to human health. Both thisstudy and a recent report from the National Acad-emy of Science conclude that decreasing sulfur di-oxide emissions would reduce sulfur deposition byroughly the same proportion. For these reasons,

. 3“

Photo credit: Roger Chen

A sulfate particle transformed from sulfur dioxide gasin a water droplet. The black soot (fly ash) speeds theconversion. Sulfate particles, when airborne, are partof a “pollutant mix” that degrades visibility and posesrisks to human health. These small particles can besuspended for several days, gradually settling to Earthduring dry periods, or rapidly washed from the air ifit rains. In either form—wet or dry-sulfur compounds

are major contributors to acid deposition.

sulfur dioxide is the logical focus for a programto control acid deposition in the Eastern UnitedStates.

Adding nitrogen oxides controls to the pro-gram is a reasonable next step if additional re-source protection is desired. Nitrogen oxidesemissions are expected to increase more rapidly

Ch. 1—Summary ● 1 7

over the next few decades than sulfur dioxide emis-sions. During the spring—a vulnerable period foraquatic life—both nitrogen and sulfur compoundsfound in melting snow travel freely through water-sheds to bodies of water and contribute to acidifica-tion. Reducing nitrogen oxides emissions wouldalso help lower regional ozone levels,

In the West, nitrogen compounds may contrib-ute as much or more to precipitation acidity assulfur and, thus, should be considered if a nation-wide control program is desired.

● How Widespread Should a ControlProgram Be?

Both pollutant sources and resources sensitiveto the effects of transported air pollutants arescattered across the Eastern United States. Be-cause pollutants can travel hundreds of miles,programs to protect sensitive resources must en-compass much of this area. Four regions are po-tential candidates:

1.

2.

3.

4.

The 21 States east of the Mississippi River andnorth of (and including) Tennessee and NorthCarolina, which receive the greatest levels ofacidity. This region excludes several con-tiguous States that are large emitters.The 31 States bordering and east of theMississippi River, which emit 83 percent ofthe Nation’s sulfur dioxide and 66 percent ofits nitrogen oxides. This region has been thefocus of most legislative proposals to date.The 37 States east of the Rocky Mountains,which emit 89 percent of the Nation’s sulfurdioxide and 85 percent of its nitrogen oxides,The 48 contiguous States.

● What Level of Pollution Control ShouldBe Required?

Possible choices for further emissions control pro-grams range from modest control (which wouldhold overall emissions at current levels) to large-scale emissions reductions. The decision of howmuch to reduce emissions involves two importantcomponents: the scientific question of therelationship between emissions reductions and re-source protection, and the policy question of thesocially desirable level of protection.

Most of the control programs proposed in recentsessions of Congress have aimed at reducing emis-sions by 8 million to 10 million tons per year below1980 levels. Although the effects of such reductionsare hard to predict, this study estimates that re-ductions of 8 million to 10 million tons per yearbelow 1980 levels are likely to protect all but themost sensitive aquatic resources in many areasreceiving high levels of acid deposition. Thoseareas now receiving the highest levels of depo-sition— western Pennsylvania, for instance—would also benefit from reductions of this mag-nitude, though some risk of damage would stillbe present. Risks of damage to forests, agriculture,materials, and health would likewise be reduced,and visibility would improve. A control programof this magnitude would cost about $3 billion to$6 billion per year. Costs would rise steeply ifgreater resource protection were desired.

More modest reductions, eliminating 2 millionto 5 million tons of sulfur dioxide per year fromexisting sources, could be achieved for about $1 bil-lion per year. Such a program would, at a mini-mum, offset expected emissions increases from util-ity and industrial growth, and might decreaseemissions by 2 million to 3 million tons per yearby the year 2000. Some resource improvementmight result, or degradation might be slowed, butit is impossible at present to gauge by how much.

● By What Time Should Reductions BeRequired?

Significant emissions reductions from existingsources would take at least 6 or 7—and possibly10 or more—years to implement, given the plan-ning, contracting, construction, and other stepsthat would be necessary. Waiting 4 to 6 yearsfor the results of the Federal research programcould increase the time required to reduce depo-sition to 10 to 16 years or more. Although re-source damage will continue, it is impossible to pre-dict how much damage might occur to resourcesduring this additional delay, or how much moreefficient a control program designed at the end ofthe decade might be. Because of the time neededfor planning, a control program initiated in thenear future would not involve major expendi-tures for at least 5 years. Control legislation could

18 ● Acid Rain and Transported Air Pollutants: lmplications for Public Policy

be modified with relatively modest cost penaltiesuntil 2 to 3 years before the compliance date, atwhich point major construction expenditures wouldhave to begin.

● What Approach to Control Should BeAdopted?

Two general approaches are currently used forenvironmental regulation: ‘‘source-based’ regu-lations and ‘ ‘environmental quality’ standards.Source-based programs directly regulate the quan-tity of pollution allowed from emission sources. Pro-grams based on environmental quality standardsset goals or standards for resource exposure to pol-lutants; steps are then taken to meet these goals.Such a program requires a well-developed under-standing of the transport, transformation, andeffects of pollutants. The knowledge needed to im-plement an environmental quality standard foracid deposition is not yet available and may notbe for at least a decade. This study therefore con-cludes that a source-based program, which reg-ulates emissions directly, is the only approachavailable now for controlling acid deposition.Such a program could specify, for example, max-imum allowable emission rates (in pounds of pol-lutants per quantity of fuel burned) or maximumallowable statewide emissions (in tons of pollutantsper year). A source-based approach could also limitemissions by mandating the use of specific tech-nologies such as scrubbers or coal washing.

● How Should Emissions Reductions BeAllocated?

If Congress decides to mandate emissions reduc-tions directly, it can either set a reduction formulathat applies to all or some of the sources within aState, or it can set an overall reduction level foreach State and allow the State to allocate emissionsreductions within its borders. Congress could alsoset specific environmental protection goals, includ-ing economic considerations, and direct the Envi-ronmental Protection Agency (EPA) to develop anallocation plan to meet those goals.

Allocation formulas can take many differentforms. For example, emissions could be reduced

by an equal percentage in each State regardless ofwhether the State is a relatively high or low emit-ter. Alternatively, allowable emission rates couldbe set, requiring the greatest reductions fromsources that emit the greatest amounts of pollutionper unit of fuel burned or similar measure. Mostlegislative proposals to date have followed the lat-ter approach. A formula could be based on utilityemissions alone or statewide total emissions. Alloca-tion formulas differ in their resulting geographicpatterns of emissions reductions and administrativecomplexity.

● Who Pays the Costs of EmissionsReductions?

The full costs of pollution control could be borneby those sources required to reduce emissions. This“polluter pays” philosophy is the traditional ap-proach to environmental regulation; in the caseof transported air pollutants, however, the cul-pability of particular sources for specific resourcedamage is difficult to assess. Thus, some advo-cate spreading the costs of a control program toa larger group through such mechanisms as a taxon electricity or emissions. Revenues would goto a trust fund, to be used to help finance controltechnology. Such cost-sharing mechanisms, how-ever, can impose costs on areas that have takenaction in the past to control emissions or thatalready have low emissions.

● What Can Be Done To MitigateEmployment and Economic Effects of aControl Policy?

To reduce employment dislocations resultingfrom increased demand for low-sulfur coal, Con-gress could require the use of control technologiesdesigned for high-sulfur coal or require plants touse locally mined coal. Mandating the use of scrub-ber technologies could increase the costs of emis-sions reductions by about 25 to 50 percent for alarge-scale program. Alternatively, if utilities areallowed to switch from high- to low-sulfur coal,workers or communities affected by the switch couldbe compensated.


To reduce the financial strain on specific utilitiesor their customers, Congress could establish a trustfund (as described under the previous question) tohelp pay for pollution control equipment.

Options

Congress could design a control program byselecting alternatives from each of the eight deci-sion areas summarized above. Obviously, manycombinations are possible; three representative op-tions are presented below.

Option A-1: Mandate small-scale emissionreductions.

A small-scale program would logically focus onfurther controlling sulfur dioxide emissions—themajor manmade acidifying pollutant in the East-ern United States—within a 20- to 30-State regionproducing and receiving the greatest acid deposi-tion. Two million to three million tons of sulfur di-oxide emissions could be eliminated from existingsources for under $1 billion annually; 5 million tonsper year could be eliminated for about $1 billionto $1.5 billion annually.

Control programs of this size would offset ex-pected emissions increases of 2 million to 3 milliontons per year by the year 2000, holding levels ofacid deposition about constant or reducing themslightly below current levels. Such a program couldbe enacted alone, or as the first phase of larger pro-grams discussed below, making the latter phase con-tingent on results of ongoing research.

Option A-2: Mandate large-scale emissionsreductions.

A large-scale program similar to those proposedduring recent sessions of Congress would reducesulfur dioxide emissions by 8 million to 12 milliontons per year. It could be confined to the EasternUnited States or applied nationwide and could alsoinclude reductions in nitrogen oxides emissions.

We estimate that such a program would protectall but the most sensitive lakes and streams in manyareas receiving high levels of acid deposition, Areasreceiving the greatest levels of acidity, however, stillmight not be completely protected. Risks of dam-

age to forests, crops, materials, and health wouldalso be reduced and visibility would improve.

The costs of such a program could range from$2 billion to $3 billion per year to $6 billion to $8billion per year, depending on its size and design.Congress might choose to spread some portion ofcontrol costs across a larger group than just thosesources required to reduce. A trust fund generatedby a tax on electricity or pollutant emissions couldbe established for this purpose. Congress could alsomandate or subsidize the use of control technologyto minimize job dislocations associated with switch-ing from high- to low-sulfur coal.

Option A-3: Specify environmental qualitygoals or standards.

Rather than mandating specific emissions reduc-tions, Congress could set environmental protectiongoals (including economic considerations, if desired)and direct EPA to establish a plan to achieve them.Because the tools needed to establish such a pro-gram are not yet available, this approach would notbe feasible in the near future. It could, however,be preceded by small-scale, mandated reductionsdescribed earlier if Congress desired some emissionsreductions within a decade. The compliance datefor the remainder of the program might be set forearly in the next century, which might allow enoughtime to develop the necessary modeling techniques,establish the standard, and achieve the required re-ductions.

Approach B: Liming Lakes and Streams ToMitigate Some of the Effects ofAcid Deposition.

Discussion

Several chemicals can be used to temporarilytreat acidified aquatic ecosystems. Mitigating theeffects of acid deposition on other sensitive resources(e. g., forest soils) is not yet technically or econom-ically feasible.

Adding large quantities of lime to water bodieshas been effective in counteracting surface wateracidification in parts of Scandinavia, Canada, andthe United States. These programs have signifi-cantly improved water quality at a number of lakes

20 Acid Rain and Transported Air Pollutants: Implications for Public Policy

Photo credit: Ted Spiegel

Sulfur dioxide being emitted from the Kingston powerplant in Tennessee. Sulfur dioxide gas is invisible to the nakedeye, but can be seen in the inset (upper right) with the aid of a special camera filter. The two 1,000-ft smokestacks werebuilt in 1976, replacing the nine smaller stacks built with the plant during the mid-1950’s. The tall stacks help the plant

comply with local air-quality regulations, but disperse pollutants more widely.

and ponds, permitting fisheries to be maintained,Once begun, liming must be repeated every fewyears to prevent reacidification and buildup of toxicmetal concentrations. Not all lakes and streams,however, respond sufficiently to liming to reestab-lish aquatic life, and little is known about the eco-logical consequences of continued liming.

Federal funding over the last several years per-mitted only a few research projects on the effectsof liming to be undertaken each year. Several billsintroduced during recent sessions of Congress pro-posed additional Federal support for mitigation pro-grams. The Administration recently proposedabout $5 million for liming research for fiscal year1985. Funding at this level would provide more in-formation on the feasibility of liming as a way tocounteract the effects of acid deposition on sensitivelakes and streams. Such information would be ex-tremely useful regardless of whether an emissionscontrol program is adopted. Specific options avail-able to Congress for promoting mitigation researchare listed below.

Options

Option B-1: Expand current Federal mitigationresearch efforts under the NationalAcid Precipitation AssessmentProgram (NAPAP).

Federal funding through NAPAP for research onmitigation techniques—primarily liming—has beenvery modest. Congress could make more researchfunds available to expand this program so that itwould include lakes and streams of varying geo-logical, geographic, and biological conditions.Long-term monitoring of biological and chemicalchanges in limed water bodies should be an integralpart of the program to determine frequency andeffectiveness of liming, as well as secondary effectsof this chemical alteration. Such a program couldaid the Fish and Wildlife Service in developingguidelines that States, local communities, and pri-vate interests could use to mitigate the effects ofacidification.

Option B-2: Expand Federal-State cooperativeefforts for treating acidified surfacewaters and assessing results.

Funds to assess the effectiveness of water treat-ments are available under the existing Dingell-Johnson Act, which imposes a 10-percent tax onthe wholesale cost of fishing tackle for projects tobenefit recreational fishing. However, States cur-rently do little mitigation-related work with thesefunds. Congress could direct additional resourcestowards mitigation activities by placing re-quirements on the use of these funds, by makingmore funds available, or by establishing newFederal-State cooperative programs.

Option B-3: Establish demonstration projectsfor acidified water bodies onFederal lands.

Congress could direct the Fish and Wildlife Serv-ice or the Forest Service to establish programs totreat selected lakes and streams on Federal landsand monitor their chemical and biological responses.

Approach C: Modifying the CurrentResearch Program (NAPAP) ToProvide More Timely Guidanceto Congress.

Discussion

Under the Acid Precipitation Act of 1980 (TitleVII of the Energy Security Act of 1980, Public Law96-294), Congress created an interagency task forceto carry out a comprehensive 10-year research andassessment program on acid deposition. After 2years of planning, the task force presented Con-gress with the National Acid Precipitation Assess-ment Plan. According to this plan, an integrated,policy-related assessment is to be completed by 1987and updated by 1989—a schedule that many mem-bers of Congress and public interest groups feel istoo slow.

Several bills have proposed accelerating the plan.Such action has several disadvantages and is un-



This researcher is measuring the acidity of a lake in the Adirondack Mountains, N.Y. Research sponsored by both theFederal interagency research program and such private groups as the Electric Power Research Institute has helpedscientists understand some of the causes and consequences of acid deposition. A continuing, strong research programis needed, regardless of the outcome of emissions control legislation. Two important areas include: 1) effective methods

to treat already damaged lakes and streams (options B-1 to B-3), and 2) research on combinedair pollution stresses

likely to provide guidance to policy makers in theshort term. Redesigning the research schedulewould consume a substantial amount of time andeffort; moreover, many of the currently plannedstudies cannot be completed in the shorter timessuggested. Accelerating the program might limitlonger term studies, which are of great importancefor evaluating and implementing any control pro-gram eventually put in place.

A strong, continuing research program is a nec-essary part of any strategy Congress might chooseto address the problem of acid deposition. CurrentFederal research efforts could be strengthened inseveral ways. Option C-1 below is appropriate ifCongress decides to wait several years to reconsider

to forests (option C-3).

an emissions control program; option C-2 is appro-priate if Congress acts now to control acid deposi-tion. Option C-3 could be adopted in either event.

Options

Option C-1: Establish a two-track researchprogram.

In the absence of a legislated emissions controlprogram, Congress could establish a policy assess-ment effort to be completed at an earlier date. Theprogram could be assigned to either the existinginteragency task force, or to a separate group en-tirely. Such a “two-track’ program, leaving thecurrent program largely intact, could analyze a


series of control options within 2 or 3 years. Thiseffort would need to begin almost immediately andtherefore rely primarily on currently available in-formation. Though this assessment would, by ne-cessity, be based on less complete information thanone begun several years from now, it could pro-vide a common set of control costs estimates, depo-sit ion reductions, and similar information aboutalternative scenarios for policymakers to consider.The assessment could provide important informa-tion for considering the initiation of a control pro-gram; the present, longer term effort would be com-pletd in time to reevaluate a control program, ifenacted, beforc major expenditures occurred.

Option C-2: Redirect the research program if acontrol program is legislated.

Though the National Acid Precipitation Programwas established as a long-term (10-year) effort, theenabling legislation does not explicitly address itsfate if control legislation is passed. Maintaining theprogram in such a case, with some modifications,would have several benefits. Continued long-termmonitoring and research will be necessary toevaluate the effectiveness of a control program afterits passage, providing the opportunity to modifythe control strategy if necessary. Also, with someredirect ion, the program would provide valuableguidance on implementing the control plan throughthe 1990’s.

Option C-3: Broaden the ongoing research toinclude other transported air pol-lutants.

The Acid Precipitation Act of 1980 establishedan innovative, interagency research program ad-dressing acid deposition. However, the effects ofacid deposition on many resources— in particular,forests, crops, and materials—are difficult to sep-arate from other pollutant stresses. Similarly, re-ducing emissions provides benefits in addition tothose associated with reduced levels of acid depo-sit ion, for example, improved visibility. Congresscould use the existing interagency structure andbroaden NAPAP’s mandate (and funding) to in-clude research on other air pollutants. For exam-ple, recent studies showing forest productivity ydeclines in the Eastern United States have raised

concerns about the combined stress from acid depo-sition, ozone, and heavy-metal deposition. An in-tegrated approach to studying such pollutant mixescould both strengthen the current research effort,and, perhaps more important, provide guidance toCongress about the more general problem of trans-ported air pollutants.

Approach D:

Discussion

Modifying Existing Provisionsof the Clean Air Act To EnableEPA, States, and Countries ToMore Effectively AddressTransported Air PollutantsOther Than Acid Deposition.

The Clean Air Act was designed to control air-borne concentrations of pollutants known to en-danger public health and welfare. No provisionsin the act provide a direct means of controlling thedeposition of air pollutants or their transformationproducts.

Provisions were added to the act during its 1977reauthorization to prevent a States emissions fromcausing violations of National Ambient Air QualityStandards in other States or contributing to a pol-lution problem in other countries (sees. 110and 115, respectively). These provisions are wordedvery generally and contain no guidelines for deter-mining the sources or effects of transported airpollutants.

Several States have attempted to use these pro-visions, either through petitions to EPA or litiga-tion in Federal courts, to force other States to curbemissions. To date, few of these suits or petitionshave been settled. Recent decisions by Federalcourts suggest that they are not prepared to requireEPA to give broader consideration to interstate pol-lution than it does now.

To make the Clean Air Act a more effectivemeans of controlling interstate and internationalpollution transport, Congress could modify the actin several ways. The changes discussed below wouldbe helpful for addressing many transported air pol-lution disputes, but would probably be of limiteduse for such geographically widespread problemsas acid deposition.

99-413 0 - 84 - 3 : QL . 3


Options

Option D-1: Amend requirements forconsidering interstate pollutionunder the Clean Air Act.

Section 110 of the Clean Air Act is a verygeneral provision that offers little guidance on howmuch interstate pollution is permissible, whetherthe law applies to the individual sources or to thecumulative sources throughout a State, and howinterstate effects are to be demonstrated. Congresscould amend the section to clarify EPA responsibil-ities for assessing and regulating interstate pollu-tion. In addition, Congress could modify pro-cedures for review of interstate pollution petitions(contained in sec. 126 of the act) to allow Statesto move on to the judicial appeals process if EPAdoes not act on the petitions before it. Such actionwould help eliminate the current bottleneck ofStates’ petitions within EPA. Again, such changeswould probably not make the Clean Air Act moreeffective in dealing with acid deposition, as the sec-tion applies only to pollutants for which National

Ambient Air Quality Standards exist, Such changesmight, however, assist States seeking relief fromtransported air pollutants currently regulated underthe Clean Air Act.

Option D-2: Amend the internationalprovisions of the Clean Air Act.

Section 115 of the Clean Air Act was designedto address local pollution effects occurring acrossan international boundary. As with section 1 IO(a)(2)(E), its lack of specificity makes it an unwieldytool for controlling air pollutants transported overlong distances. Congress could amend this sectionto make it a more effective means of controllingthese pollutants, for example, by identifying anappropriate international agency (e. g., the Inter-national Joint Commission) or providing a mech-anism to establish bilateral commissions to addresssuch problems. Such mechanisms might assist ef-forts to settle future international air pollutiondisputes.

Chapter 2

The Policy Dilemma

Contents

Page

The Pollutants Addressed in This Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Why Transported Air Pollutants Are an Issue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28Public Concerns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28Why Transported Pollutants Are a Federal Concern . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29

Characteristics of the Policy Debate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30Disagreements Over Facts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30Distributional Issues. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30Disagreements Over Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Risk and Uncertainty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Key Scientific Uncertainties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32Uncertainty About the Extent and Location occurrent Damages . . . . . . . . . . . . . . . . . . 32Uncertainty About Future Damages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33Uncertainty About the Origin of Observed Levels of Transported Pollutants . . . . . . . . 34Uncertainty About the Effectiveness of Emissions Reductions for Reducing Levels of

Transported Pollutants at Desired Locations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36Uncertainty About Whether a Research Program Will Provide Significant New Information 36

FIGURE

Figure No. Page

10. Processes and Environmental Effects of Acid Deposition . . . . . . . . . . . . . . . . . . . . . . 28

Chapter 2

The Policy Dilemma

Fossil fuels are vital to the U.S. economy’s pro-duction of goods and services. However, burningthese fuels also produces large quantities ofpollutants— substances that, once released into theatmosphere, can damage natural resources, health,agricultural crops, manmade materials, and visi-bility. Consequently, our Nation’s laws and policiesmust strike a balance between the economic bene-fits and the environmental risks of fossil fuel com-bustion and other pollution-producing activities.

This assessment focuses on one class of air pol-lutants: those that are transported over large re-gions, either in their original form or as chemical-ly transformed products. Such pollutants includeacid deposition, ozone, and airborne sulfate. Thecurrent Clean Air Actl was designed to ameliorate

‘Clean Air Act Amendment of 1977, Public Law 95-95 (Aug. 7,1977), as amended,

local-scale pollution problems, and does not directlycontrol pollution transport across hundreds of miles.

Over the past several years, controlling pollutantsthat contribute to acid rain has become a major pol-icy issue. The House Committee on Energy andCommerce and the Senate Committee on Environ-ment and Public Works—the committees that over-see the Clean Air Act—requested OTA to assesswhat is known about transported air pollutants, in-cluding the benefits and costs of controlling them.OTA’s assessment primarily addresses potential ef-fects in the eastern half of the United States, focus-ing on the risks of damage to sensitive resources,the economic risks that arise from further control-ling pollution emissions, and how these risks aredistributed among different groups and regions ofthe country. Policy alternatives available to Con-gress are also presented.

THE POLLUTANTS ADDRESSED IN THIS STUDY

Acid deposition, ozone, and airborne sulfate areproduced from three air pollutants: sulfur dioxide,nitrogen oxides, and hydrocarbons. Acid deposi-tion, commonly referred to as ‘‘acid rain, involvesa variety of pollutants deposited in both wet anddry forms; it results from sulfur and nitrogen ox-ide gases, sulfates and nitrates (transformationproducts of these gases), and from interactions withother chemicals in the atmosphere. Figure 10 illus-trates the pathways these pollutants travel throughthe environment. Both directly emitted or ‘ ‘pri-mary pollutants and transformed or ‘‘secondarypollutants contribute to acid deposition. Both canbe of concern on the local scale as well as on a re-gional scale. A pollutant can be returned to theEarth’s surface within an hour or travel in the at-mosphere for longer than a week, depending on itschemical properties, and factors such as weatherpatterns and other pollutants present in the at-mosphere.

Besides contributing to acid deposition, thesecondary pollutants addressed in this study —sul-fates, nitrates, and ozone—are of concern for otherreasons. Regional visibility degradation is closelycorrelated with concentrations of airborne sulfateparticles. Sulfate particles in the atmosphere are alsosmall enough to be deeply inhaled, and are thusof concern for their effects on human health.Ozone—formed in the atmosphere from nitrogenoxides and hydrocarbons—is injurious to plant lifeand of concern to human health.

Secondary air pollutants have several factors incommon:

1. they can form over periods ranging fromhours to days and travel hundreds to possiblythousands of kilometers;

2. they cannot be controlled directly, but onlyby controlling the pollutants from which they

27

28 ● Acid Rain and Transported Air pollutants: Implications for Public Policy

10.—Processes and Environmental

SOURCE: Adapted from The Acid Precipitatlon Problem (Corvallis, Oreg.: U.S. Environmental Protection Agency, Environmental Research Laboratory, 1976).

3.

are formed (and possibly other pollutants that 4. they manifest themselves in several ways—determine their rates of transformation); e. g,, sulfate contributes both to acid deposi-different secondary pollutants result from the tion and to reductions in visibility.same primary pollutants—e. g., nitrogen ox-ides can react to form both nitrates and ozone;and

WHY TRANSPORTED AIR POLLUTANTSARE AN ISSUE

Public Concerns

Current evidence indicates that acid depositionhas significant adverse effects on lakes and streams.Additionally, scientific concerns have been voicedover potentially significant effects on forests andsoils, agricultural crops, manmade and naturalmaterials, visibility, and human health. Recogniz-ing this risk of damage, some individuals andgroups have called on the Federal Government tocontrol pollutant emissions more stringently than

current laws require. They cite large numbers ofacidified lakes and streams, observed forest declinesin polluted areas of Western Europe and EasternNorth America, experiments showing crop dam-age, and deterioration of historic structures asevidence that air pollutants are causing widespreaddamage to important natural, economic, and cul-tural resources. Recommendations for additionalemissions control have come, for example, from theNational Commission on Air Quality, the NationalGovernors’ Association, the State and Territorial

Ch. 2—The Policy Dilemma * 29

Air Program Administrators, study groups of theNational Academy of Sciences, and the 1982 Stock-holm Conference on the Acidification of the En-vironment.

Others, pointing to uncertainties about the causesand consequences of transported pollutants, areconcerned that further emissions controls may bemandated prematurely. They suggest that pollu-tion transport processes, potential effects, and alter-native mitigation strategies are poorly understood;thus, further controlling emissions now may wastemoney and impose unreasonable costs on industryand the public. Over the past several years, suchconcerns have been voiced by the U.S. Environ-mental Protection Agency (EPA), the Departmentof Energy, the Business Roundtable, and the U.S.Chamber of Commerce. Reducing total sulfur diox-ide emissions by more than about 25 percent in theEastern United States is estimated to cost in thebillions of dollars annually. Efforts to controltransported air pollutants through stringent sulfurdioxide emissions controls could increase electrici-ty rates as well as displace mining jobs by reduc-ing demand for high-sulfur coal.

Transported air pollutants also raise significantequity issues. Those served by the activities gen-erating acid rain and ozone can be different fromthose who incur resource damage. Similarly, par-ticular groups and regions might bear an unequalshare of the costs of controlling transported airpollutants.

Why Transported Pollutants Area Federal Concern

Transported air pollutants have become an issuefor potential Federal action because they crosspolitical boundaries. The current Federal systemof pollution control relies on State-level abatementprograms to limit pollution levels within individualStates. * However, no effective means of control-

ling extensive pollution transport across State linescurrently exists. Transported pollutants also crossthe international boundary both into and fromCanada. Article 1, Section 10 of the Constitutionprohibits States from entering into agreements withforeign nations without the consent of Congress;thus, any pollution control agreements with Canadawould require Federal action. * *

Existing Federal air pollution control mecha-nisms are governed primarily by the Clean Air Act,which Congress is now considering for reauthoriza-tion. To date, control strategies developed underthe Act have focused on controlling local ambientair concentrations. However, many observers havequestioned the effectiveness of this approach forcontrolling transported air pollutants.

● ● The United States and Canada signed a Memorandum of Intentin August 1980, establishing a bilateral research plan to investigatetransboundary air pollution and pledging work toward a bilateral ac-cord on transboundary air pollution. Negotiations began on June 23,1981, and are still in progress.

● National emissions limits for new sources of pollution (New SourcePerformance Standards) are in place to control future pollutionemissions.


CHARACTERISTICS OF THE POLICY DEBATE

Several aspects of transported air pollutants haveshaped the public policy debate over whether or notto further control pollutant emissions at this time.First, scientific uncertainty exists over the currentseverity and geographic extent of the damages at-tributable to transported air pollutants, as well asover the timeframe in which further damage mightoccur. Second, and of great political importance,transported air pollutants pose a distributionalproblem, having intersectoral, interregional, inter-national, and intergenerational equity aspects.Third, significant disagreements in values exist overhow to balance the costs of controlling pollutantsand the environmental risks posed by pollution.

Disagreements Over Facts

Debate over scientific understanding of trans-ported air pollutants is perhaps the most visibleaspect of the policy controversy. Many assert thatthe causes and consequences of acid deposition areboth sufficiently understood and significant to war-rant immediate action to control it. Others empha-size the complexity of the phenomena involved, andargue that no regulatory strategy can be justifiedon the basis of existing scientific knowledge.

Scientific uncertainty is not new to air pollutionpolicy. The continuing controversy over the natureand magnitude of health risks—the critical measurefor setting local air quality standards—illustratesthe difficulty of unambiguously documenting thescientific basis for regulation. Similarly, the extentto which transported air pollutants affect health,crops, visibility, materials, forests and soils, andlakes and streams is uncertain. Current inabilityto quantify these relationships precludes agreementas to whether the benefits of reducing pollutantlevels would justify the costs involved in further con-trolling emissions.

Because some types of air pollutants can be trans-formed, dispersed, and transported over long dis-tances, identifying the specific emission sourcesresponsible for resource damage in a particular areais extremely difficult. Consequently, designingemission control policies for transported pollutants

becomes difficult both analytically and politically:analytically, because the sources that can most ef-ficiently reduce deposition in the affected areas maynot be readily identifiable; politically, because plac-ing the burden of control on certain regions mayappear to be arbitrary or inequitable,

Distributional Issues

The distributional aspects of transported airpollutants further complicate the policy dilemma.Pollution control, by affecting the relative pricesof various products, benefits economic activities thatare inherently less polluting, or that can reduce pol-lution less expensively, at the expense of more pol-lution-intensive goods and services. But the geo-graphical scope of transported air pollutants createsseveral distributional issues not present in conven-tional, local air pollutant problems.

Within the United States, winds carry pollutantsover long distances, so that activities in one regionof the Nation may contribute to resource damagein other regions. Many of these activities primari-ly benefit the source region, while some of theircosts, in terms of resource damage caused by theirwaste products, fall elsewhere. Long-range pollu-tion transport thus redistributes benefits and costsamong regions. Programs to control transportedair pollutants would also have interregionaldistribution aspects. The costs of controlling emis-sions might be imposed primarily on source regions(depending on the scheme for allocating costs),while the major benefits of reducing emissionsmight accrue primarily to downwind, receptor re-gions.

Winds also carry pollutants over national bor-ders, posing an international as well as an inter-regional distribution problem. About three to fivetimes more pollution is transported from the UnitedStates to Canada than reaches this country fromCanada.2 The Canadian Government asserts thatfossil fuel combustion in the United States is damag-

2United States-Canada Memorandum of Intent on TransboundaryAir Pollution, Executive Summary, Work Group Reports, February1983.

Ch. 2—The Policy Dilemma ● 3 1

ing lakes and streams, and might damage forests,in Eastern Canada; consequently, Canada is pay-ing some of the costs of U.S. economic activities.Federal and provincial Ministers of the Environ-ment have pledged to reduce sulfur dioxide emis-sions by 50 percent in Eastern Canada by 1994 andurged the United States to undertake parallel emis-sions reductions. Distributional equity questionswould still exist if the two nations undertake fur-ther control programs, in that the United States andCanada might benefit differentially from reducedtransboundary pollution.

The intergenerational aspects of transported airpollutants raise yet another equity issue. Both theappearance of harmful effects and the recovery ofdamaged resources may lag behind changes in pol-lution levels. For instance, lake and stream acidi-fication and forest damage may take on the orderof decades to occur. Because acid deposition maydiminish a watershed’s ability to neutralize futureacid inputs, future resource damages may dependon the total amount of deposition an area has al-ready received. In addition, resources may requirea relatively long period of time to recover follow-ing a reduction in the level of acidic inputs. If boththe onset and amelioration of adverse effects involveextensive delays, the amount of acid deposition pro-duced by one generation could affect the qualityof ecological and other societal resources availableto future generations.

Disagreements Over Values

Even if a scientific consensus existed on themagnitude of the problem of transported pollutants,policy choices would still be complicated by lackof agreement over how to promote economic de-velopment while protecting the environment. Al-though the concept of a tradeoff between these twovalues is widely accepted, various individuals andgroups differ sharply on where the balance shouldbe struck.

Disagreements over facts and values are inter-twined. Differing value structures lead various in-dividuals and groups to draw quite different con-clusions from the same body of scientific informa-tion. Widespread recognition of scientific uncer-tainties has focused the policy debate on whetherboth the magnitude of damage involved and theeffectiveness of control efforts are sufficiently knownto pursue emissions reductions. This dispute in-volves both relatively objective issues of science,e.g., how reducing sulfur emissions might affect sul-fur deposition in certain areas, and subjective issuesof values, e. g., what level of scientific certaintyand/or what degree of damage is required to justifyundertaking a control program.

RISK AND UNCERTAINTY

Scientists can describe potential resource damage control expenditures, and the distribution ofand regions of the United States most susceptible these risks among different groups and regionsto damage from transported pollutants, but they of the country.cannot precisely quantify what levels of damagehave already occurred or could occur in the future. Risk, in the sense used in this report, refers toSimilarly, analysts can estimate the costs of alter- some possible, harmful outcome—either resourcenative control strategies, and who might bear these damage or excessive control costs. Three conceptscosts, but how effective these control strategies are important:would be for avoiding resource damage cannot becalculated with confidence. Given the difficulty of 1.quantifying the relationship between reducing emis- 2.sions and preventing resource damage, Congressmust base near-term policy decisions on the risks 3.of resource damage, the risks of unwarranted

a potential for harm exists;there is some uncertainty about whether theharm will actually come to pass; andif it does, there is uncertainty about how ex-tensive it will be.


Throughout this report, OTA describes the risksof controlling or not controlling transported airpollutants, emphasizing those risks with potentiallysignificant consequences for society. To put this in-formation in perspective, wherever possible, wehave tried to describe the uncertainty in estimatesof the magnitude and extent of the potential harm,as well as how likely such harm is to occur.

Assessments of risk such as those presented inchapter 3, and the regional descriptions presented

in chapter 5, focus on potential consequences, notnecessarily the consequences that will, in fact, oc-cur. Uncertainty—stemming from limitations indata and understanding—precludes drawing defin-itive scientific conclusions. Nonetheless, uncer-tainty does not remove the risks to which societyis actually subjected, although it makes theserisks substantially more difficult to describe.Five key uncertainties, chosen for their relevanceto the policy debate, are presented below.

KEY SCIENTIFIC UNCERTAINTIES

Later chapters of this report will describe whatis at stake in decisions to control or not to controltransported air pollutants. This chapter outlines keyuncertainties to provide an overview of current de-bates within the technical and scientific communi-ty. Each of these uncertainties will also be discussedthroughout the report as appropriate to the issuebeing addressed.

Five key uncertainties are especially relevant tocongressional decisions about transported air pol-lutants. These include controversies about:

1.2.

3.

4.

5.

the extent and location of current damages,future damages (whether they are cumulativeand/or irreversible),the geographic origins of observed levels ofpollution,the effectiveness of emissions reductions forreducing current levels of transported pollut-ants, andwhether a research program will provide sig-nificant new results.

These scientific uncertainties affect several policyconcerns, including:

●

●

●

making air pollution control policy as fair aspossible, i.e., providing some legal recourseto those bearing the risks of damage, and (ifa control program is adopted) distributing costsof control fairly;minimizing cumulative and irreversible dam-age, and their intergenerational implications;weighing the risk of damage against gains that

might be achieved by waiting for better infor-mation or improved technology; and

. assuring that the societal benefits of a controlprogram justify the cost.

Uncertainty About the Extent andLocation of Current Damages

Scientists are certain that transported air pol-lutants have caused some damages. At issue isthe severity of the damage, whether it is fairlylocalized or widespread, and which resources areaffected. For example, there is little question thatacid deposition damages lakes, and ozone harmscrops. The uncertainties revolve around how manylakes and streams and what quantity of crops. Forthese and other resources, the risks of extensivedamage over large parts of the United States aresubstantial. Chapter 3 summarizes the aggregaterisks in the Eastern United States for a number ofaffected resources; chapter 5 describes the regionalpatterns of these risks using an extensive series ofmaps. Appendixes discuss each resource of concernin greater detail.

For certain concerns, such as the extent of dam-age to forests from acid deposition, the uncertain-ties are so large that it is difficult to describe thepatterns or magnitude of the risk. Damage to forestsfrom ozone, and the effects of toxic metals releasedinto drinking water due to acid deposition, also fallinto this category. The report also discusses these

Ch. 2—The Policy Dilemma 33

types of risks, presenting geographical patternswhere possible.

Uncertainty About Future Damages

Growing scientific recognition that trans-ported pollutants are linked to observed damagesintensifies concern over the potential for futuredamage, even if current damages are not exten-sive. Of particular importance is the extent towhich damages are cumulative and/or irre-versible.

The Extent to Which Damages Are Cumulative

For some resources, pollution-related damagesmight worsen over time if pollution remains atabout current levels. For short-lived species, suchas crops harvested annually, this is not a relevantconcern. Damage to this year’s crops from ozone—and potentially from acid deposition—is caused

only by current levels of pollution. However, forlonger lived species such as trees, cumulative dam-age is of concern. Ozone injury and potential aciddeposition-related damage to forests maybe sma11in any one year, but continued stress over manyyears could ultimately reduce productivity.

The portion of current aquatic resource damageattributable to the cumulative effects of depositionover many years is also uncertain. One major un-known is the degree to which years of exposure toacid deposition deplete the neutralizing capabilityof soils in the surrounding watersheds.

The extent to which damages accumulate—andover what time scale-has played a major role inthe policy debate over the risks of delaying controlaction. If damages are not significantly cumulative,delaying control action while awaiting further in-formation would not increase the level of damage

Photo credit: New England Interstate Water Pollution Control Commission

Much of the acid deposition that eventually enters a lake or stream first reaches the ground in the surroundingwatershed, and travels with runoff water over soils and bedrock


from year to year (assuming that the level of pollu-tion remains fairly constant). However, for thoseeffects of transported pollutants that are cumulative,the longer control actions are delayed, the greaterthe severity of the damage.

The Extent to Which Damages Are Irreversible

A closely coupled concern is whether damage caneasily be reversed, and if so, over what time period?Again, once ozone concentrations are reduced be-low damaging levels, direct crop damage is easilyeliminated the following year. At the other extreme,damage to monuments or other unique art objectsfrom air pollution would be irreversible.

If acid deposition is reduced, fish populationsmay be restored either by restocking or by naturalmeans. However, if surrounding soils have lost their

Photo credit: New England Interstate Water Pollution control Commission

Acid deposition might harm trees directly or alterthe soils in which they grow. However, more researchis necessary to determine to what extent current levels ofacid deposition and other transported pollutants are

involved in observed declines in Eastern U.S.forest productivity

acid-neutralizing capability, even moderate inputsof acid may prevent fish from returning for decadesunless the water body is periodically treated withlime. Similarly, if acid deposition causes nutrientsto be lost from a forest floor, forest productivity maybe impaired for many decades. The effects of a se-vere series of ozone episodes, or the potential cu-mulative effects of acid deposition, will persist inthe forest community until a new forest grows.

The potential irreversibility of resource damagemakes delaying control action until better informa-tion is obtained highly controversial. For thosedamages that are reversible, it is important to knowhow alternative levels of pollution reduction wouldaffect the extent of resource improvement. Chapters3 and 5 present estimates of the benefit to cropsand aquatic resources of reducing ozone and aciddeposition levels, although considerable uncertaintysurrounds these preliminary estimates. However,to the extent that damages are both significantlycumulative and irreversible, waiting for better in-formation would irreparably harm resources for thisgeneration and the next several to follow.

Uncertainty About the Originof Observed Levels ofTransported Pollutants

Pollutants Leading to Acid Deposition

The previous sections have outlined uncertain-ties concerning the potential benefits of reducingcurrent levels of transported pollutants. If policy-makers wish to reduce current levels of pollutants,the next logical question is, ‘‘Where are they com-ing from?” Three questions are important: 1)whether the precursor pollutants are of natural ormanmade origin; 2) whether they come from localsources or from distances exceeding hundreds ofkilometers; and 3) whether it is possible to definethe geographic origin of pollutants deposited in aparticular region. These questions are addressedbriefly in chapter 4, and in greater detail in appen-dix C.

The first two questions are not key uncertain-ties. Though pollutants of natural origin causesome acid deposition, deposition over large areasof the Eastern United States far exceeds the level

Ch. 2—The Policy Dilemma . 35

attributable to natural sources of pollutants. Inaddition, while local sources (i. e., within 30miles) do contribute to acid deposition, mostanalyses indicate that a large share of thedeposition— in some cases, over half-originatesfrom both medium-range and distant sources(i.e., greater than 300 miles away) as well.

The key uncertainty is whether scientists canreliably determine how much of the deposition inany one region originates from emissions in anyother. Computer models of varying sophisticationare available to perform such analyses, but theiraccuracy in portraying this relationship is uncer-tain. The inherent variability of weather pat-terns and the complexity of atmospheric chem-istry make it unlikely that models will ever beable to predict how much one individual sourceof emissions contributes to deposition in a smallarea. However, these models can be used to assesscurrent annual average patterns of pollutanttransport over large geographic regions—on thisscale, models reproduce observed patterns of an-nual sulfur deposition in rainfall reasonably well.Their capacity to synthesize extensive meteorolog-ical data makes these models the best available toolsfor describing the current relationship betweenemissions in one area and deposition in another.Model-based estimates of the extent of interregionaltransport for sulfur pollution are presented inchapter 4.

Model adequacy is a critical element in severalsuits and petitions by States to control transportedair pollutants under the interstate provisions of thecurrent Clean Air Act. EPA considers availablemodels inadequate to reliably analyze long-rangepollution transport; consequently, the Agency doesnot assess the effects of pollution that travels beyond50 kilometers (30 miles). However, the petition-ing States assert that available ‘ ‘long-range trans-port’ models reflect the state of the art and shouldtherefore be used by EPA.

In addition, policy-level attempts to reduce pol-lutant deposition in identified, sensitive regionswould rely to a large extent on model-based abilitiesto determine the sources of such deposition. How-ever, no amount of accurate, detailed modeling in-formation would be sufficient to eliminate policydisputes over which region’s resources should beprotected, or which region’s emissions should becontrolled.


Tracking this weather balloon by radar helps to determinehow air masses travel and mix under a variety ofatmospheric conditions. Such data are important forunderstanding how pollutants are transported and

transformed when they are aloft

Because many regions have sensitive resources,and all of them receive some deposition from eachof many emitting regions, a variety of possiblestrategies could be used to reduce deposition on sen-sitive resources. For example, decisionmakers, inresponse to equity concerns, could develop controlprograms under which multi-state regions responsi-ble for “large” shares of deposition in ‘‘several’sensitive areas bear the ‘‘greatest share’ of emis-sions reductions. Whether the broad regional pat-terns of transport described by the models are ac-curate enough for this purpose is as much a policyquestion as a scientific one.

Pollutants Leading to Ozone Formation

The same three questions apply to ozone:whether the precursor pollutants are of natural or

.- —


manmade origin, whether they are of local or dis-tant origin, and whether it is possible to pinpointthe geographic source of deposition in a specifiedregion. As with acid deposition, ozone levels overbroad regions of the United States exceed naturalbackground levels. Though locally produced ozoneis a problem in many of the Nation’s urban areas,ozone’s chemical precursors can travel long dis-tances, and elevated ozone levels are found in ruralareas downwind from emission sources. However,models of long-range ozone transport are in a rudi-mentary stage of development. Because the chem-istry of ozone formation is very complex, majoruncertainties exist over the geographic origin ofelevated ozone concentrations in rural areas.

Uncertainty About the Effectivenessof Emissions Reductions for Reducing

Levels of Transported Pollutantsat Desired Locations

Uncertainty about the effectiveness of reducingemissions as a means of controlling transported pol-lutants stems from two factors. The first-uncer-tainty about how well current models describe therelative contribution of one area’s emissions to an-other’s pollution—has been explained in the pre-vious section. While this ‘‘source-receptor’ rela-tionship cannot be defined precisely, existing mod-els can synthesize extensive meteorological infor-mation to provide broad regional descriptions. Still,the remaining uncertainty raises questions aboutthe extent to which emissions reductions in anyspecific area would reduce pollution in anotherarea.

The second unknown concerns the chemicalprocesses that transform pollutants in the at-mosphere. It is known that numerous complexchemical reactions are involved in forming ozone,airborne sulfates, and acid deposition. Uncertain-ties exist about how effective reducing emissionsof each precursor pollutant will be in controllingthe transformed products.

For example, sulfur dioxide emissions are trans-formed to sulfate, a major constituent of acid dep-osition, Reducing the total amount of sulfur diox-ide emitted will undoubtedly reduce the overallamount of deposited sulfate, but it is difficult to

quantify the reduction in deposition that a specificemissions cutback will produce in a specific area.Most analyses indicate that reducing sulfur diox-ide emissions within a broad control region willsignificantly, but not quite equally, reduce theamount of sulfur deposited in various forms inthat region. However, some scientists are uncer-tain that reducing sulfur dioxide emissions aloneis the most efficient way to control acid deposition.Because other pollutants (e. g., hydrocarbons andnitrogen oxides) can enhance or impede chemicaltransformations of sulfur dioxide, these other pol-lutants might also be controlled simultaneously toreduce acid deposition in specific geographicregions. Chapter 4 and appendix C discuss this ingreater detail.

Uncertainties about which pollutants to control,as well as the uncertain relationship between emis-sions reductions and deposition reductions, com-plicate the policy objective of reaping the greatestpossible benefit from the costs of controlling emis-sions. Scientists are unable to confidently projectthe precise pattern of deposition reductions thatwould result from a specified emissions control plan.Under these circumstances, a control program de-signed and implemented today might not producethe maximum benefits achievable for a given cost.

Uncertainty About Whether aResearch Program Will Provide

Significant New Information

One of the most difficult decisions facing Con-gress is whether to act during this reauthorizationof the Clean Air Act, or to await results from ongo-ing, multimillion dollar Federal and private re-search efforts on acid deposition. While the researchefforts are intended to reduce the uncertainty dis-cussed above, how much new insight 4 to 6 yearsof further research will provide is unknown.

For example, years to decades are required toobserve changes in many ecological processes. Pat-terns of crop yield and forest productivity typical-ly vary from year to year; separating the effect ofacid deposition from normally expected year-to-year fluctuations requires many years of data. Theprocesses of soil formation and depletion proceedon the time scale of decades. These mechanisms

Ch. 2—The Policy Dilemma ● 3 7


Collecting and testing water droplets from clouds highabove the ground in southern Ohio. Researchers also use

this airborne Iaboratory to analyze gaseous andparticulate pollutants in the atmosphere

can be artificially accelerated and studied in labo-ratories, but the extent to which such experimentsreflect real-world conditions is uncertain.

While scientists understand the basic mechanismsof acid formation and deposition, detailed knowl-edge of the complex chemistry and meteorology in-volved will require many more years of research.Ongoing efforts to evaluate the current generationof computer models that simulate atmospheric proc-esses have already taken several years, Efforts todevelop new transport and transformation modelsare underway; the number of years needed to sig-nificantly improve existing models is unknown.

Uncertainties about the progress of research pro-grams are important in considering the timetablefor policy decisions. Given the planning and con-struction efforts required to significantly reducepollutant emissions, a decision to control emissionsnow may still require 6 to 10 or more years to im-plement. Waiting another 4 to 6 years for theresults of a research program before making con-trol decisions increases the time required to re-duce deposition to 10 to 16 years. Delaying con-trol action increases the risk of resource damagebut reduces the risk of inefficient control ex-penditures. Congress could avoid this delay bymandating controls now, while retaining the optionto change the law if new research results point toalternative courses of action. To achieve compliancewithin a decade, however, expenditures would haveto begin within 6 to 8 years. If results suggestingan alternative control strategy appear much afterthis time, major expenditures may be irrevocable.

Chapter 3

Transported Air Pollutants:The Risks of Damage and

the Risks of Control

—

Contents

PageNo Congressional Action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41Resources at Risk..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41Risks of Health Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47Potential for the Courts or EPA To Rule in the Absence of Congressional Direction . 48Risk of Strained International Relations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

If Further Emissions Reductions Are Mandated . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49Utility Control Costso . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49Effects on the U.S. Coal Market . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50Effects of Utility and Industrial Financial Health . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Risk That Control May Not Be As Effective or Efficient As Desired . . . . . . . . . . . 52Effectiveness of Emissions Reductions for Achieving Desired Deposition Reductions . . 53Efficiency Concerns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Chapter 3

Transported Air Pollutants: The Risks ofDamage and the Risks of Control

As discussed previously, the risks of transportedair pollutants are amenable only to qualitative de-scriptions. Certain aspects can be described numer-ically—for example, the numbers of lakes andstreams currently altered by acid deposition, or peo-ple exposed to health risks from airborne sulfatesand other small particles. Wherever possible, thisreport also presents numerical estimates of the risksto a region’s resources, industry, jobs, and con-sumer pocketbooks, However, the substantial un-certainties associated with available data and theorymean that these numerical descriptions should beviewed as qualitative estimates, rather than exact,quantitative answers. One should not be misled bythe apparent precision of the numbers. The infor-

mation presented is intended to convey approxi-mate outcomes—in some cases with unknown mar-gins of error— and broad regional patterns.

This chapter summarizes the OTA estimates ofrisk to the Eastern United States as a whole.OTA-sponsored or in-house work provides the basisfor most of these estimates. Chapter 5 will examinewho bears these risks, by State and by economicsector. These chapters use the somewhat artificialdichotomy of mandating further emissions reduc-tions vs. maintaining the status quo as a frameworkfor describing potential consequences. Chapters 6and 7 of this report present congressional options,including interim decisions, in greater detail.

NO CONGRESSIONAL ACTION

Resources at Risk

Two factors determine the potential for resourcedamage from transported air pollutants: 1) theamount of pollution to which the resource is ex-posed, and 2) the sensitivity of resources to aciddeposition and ozone. Resource sensitivity variesfrom resource to resource—and among the specificplants, animals, soils, and materials within eachresource category. Some resources are directly af-fected by the pollution received. For example, cropsare affected by exposure to ozone, and some build-ing materials are affected by acid-producing sub-stances deposited on their surfaces.

For other resources, sensitivity also depends oncharacteristics of the local environment. For exam-ple, lakes and streams are affected primarily by theamount of acid-producing substances that eventual-ly travels through the watersheds to lakes andstreams, as well as by the acid deposition that fallsdirectly onto the surface of the water. The acid-neu-tralizing capabilities of the soil and bedrock in the

surrounding watershed help determine the suscep-tibility of water bodies to acid deposition. Aciddeposition may affect forests through subtle soilchemical changes—here again, the sensitivity of theforest resource could largely depend on soil char-acteristics.

Aquatic Ecosystems

More is known about how acid deposition affectsaquatic ecosystems—and the current extent of theseeffects—than for any other resource. Substantialevidence indicates that acid deposition alters waterchemistry in sensitive lakes and streams. Most vul-nerable are small lakes and streams in watershedsthat have little capability to neutralize acid, dueeither to the chemical composition and/or thinnessof the soils, or to terrain that is so steep or rocky

‘This section is based primarily on material from: The Institute ofEcology, “Regional Assessment of Aquatic Resources at Risk FromAcid Deposition, contractor report submitted to the Office of Tech-nology Assessment, 1982.

41


\

Photo credit: Lars Overrein

Highly acidified waters, and water chemistry changes caused by acidity, may prevent fish from developing. In theexperiment illustrated above. Brown trout eggs were placed simultaneously in waters of differing acidity. The embryos

shown at left failed to develop in acidic water (pH 4.6). The fry at rightwere raised in less acid water (pH 5.5) and appear normal

that rainfall runs over it before acid can be neu-tralized.

Fish are sensitive both to the acidity of water,and to toxic metals-primarily aluminum-that arereleased from the watershed under acid conditions.When waters become more acid than pH 5, manyfish species are eliminated and major changes inlake ecosystem processes frequently occur. Highacidity, toxic concentrations of metals such asaluminum, or some combination of the two appearto cause these changes.

Based on the predominant soil and geologicalcharacteristics in each county, OTA classifies about25 percent of the land area of the Eastern 31-Stateregion as ‘‘sensitive, i.e. , allowing the transportof acidity through a watershed to lakes and streams.Within these identified sensitive regions are approx-imately 17,000 lakes and 112,000 miles of streams—these figures provide an upper bound of theaquatic resources at risk. Only a portion of the totalnumber of lakes and streams in the sensitive regionsshould currently be considered vulnerable to acid

inputs. Small lakes and stream segments are, ingeneral, most susceptible to change. While someareas have geologic characteristics that make themsensitive to acidification, they may not receiveenough acid deposition to alter the water qualityof lakes and streams. In addition, local variationsin geology, soil conditions, and topography affectthe land’s ability to prevent acidification of waterbodies.

OTA used available water quality data fromabout 800 lakes and 400 streams throughout eightStates in the Eastern half of the United States toestimate the number of lakes and streams current-ly vulnerable to acid deposition. OTA estimatesthat about 9,500 lakes and 60,000 miles of streamscurrently have limited acid neutralizing capabilitiessuch that, given sufficient acid deposition, theymight acidify—a ‘‘best guess’ encompassing abouthalf the upper-bound estimate presented earlier.

OTA also used available water quality data, cor-recting for a percentage of lakes and streams thatmay be naturally acidic, to estimate that about

Ch. 3—Transported Air Pollutants: The Risks of Damage and the Risks of Control . 43

3,000 lakes and 23,000 miles of streams have al-ready become acidified, or have so little acid-neu-tralizing capability left that they are extremely vul-nerable to further acid deposition. This correspondsto about 20 percent of the lakes and streams foundin identified sensitive areas.

Of the approximately 50,000 lakes in EasternCanada, the Ontario Ministry of the Environmentestimates that about 20 percent, or 10,000, are cur-rently acid-altered. *

Scientists cannot yet estimate how many morelakes and streams could become acidified if currentlevels of acid deposition continue into the future.Two cumulative processes are important: 1) the po-tential loss of the soil’s ability to neutralize acid in-puts, and 2) for lakes, the accumulation of acidi-fying substances over years to decades, until lakewaters come into equilibrium with the level of dep-osition received from the watershed. The latterprocess delays lake response to acid deposition, withgreater time delays in larger lakes and lakes withslow rates of water replacement.

Many smaller acid-altered lakes and streams inthe Northeast are probably in equilibrium withpresent deposition levels. By assuming that con-tinued acid deposition will not further degrade thesoil’s neutralizing capability-the ‘ ‘best-case’ situ-ation— one can estimate improvements in waterquality that reduced levels of acid deposition mightproduce. OTA used a simple, theoretical model toproject how future changes in acid deposition levelsmight change the numbers of acid-altered lakes andstreams in the Eastern United States. If sulfatedeposition were decreased by 20 percent, OTA esti-mates that 10 to 25 percent of these water bodiesmight show improvement. If sulfate deposition werereduced by 30 percent, about 15 to 40 percent mightshow improvement. If sulfate deposition were in-creased by 10 percent, OTA estimates that acid-al-teration of lakes and streams might intensify byabout 5 to 15 percent.

Again, these are best-case estimates, assumingthat the effects of acid deposition are not cumula-tive. However, in those areas that are not in

● LI .S. -Canada Memorandum of Intent on Transboundary Air P[J -lution, Impact Assessment, Work Group 1, February 1983.

equilibrium with above-normal deposition levels,some lakes and streams might still continue to acid-ify slowly despite the reduction levels discussedabove. Such effects might be most pronounced inthe Southeast and upper Midwest.

Terrestrial Ecosystems

A variety of transported air pollutants affects bothcroplands and forested ecosystems. Ozone, a gas-eous pollutant toxic to plants, may account for upto 90 percent of air pollution-related damage tocrops. How much crop damage is due to trans-ported rather than locally produced ozone is uncer-tain. Observed effects include both damage to thequality of crops (e. g., leaf spotting) and reductionsin crop yield.

Damage to crops from acid deposition under nat-ural conditions has not yet been observed, althoughexperiments using simulated acid rain have shownreduced yields and altered crop quality. Since thechemistry of agricultural soils is already highly con-trolled with fertilizers and other chemicals, the pri-mary effects of acid deposition would likely be onthe above-ground portions of plants. The role ofpollutant mixes may also be significant, since aciddeposition seldom occurs in the absence of otherpollutants. In some cases, it appears that the pres-ence of sulfur or nitrogen oxides in the atmospheremakes crops more susceptible to ozone damage.

To assess the risks to crops from transported airpollutants, OTA has estimated the benefits thatmight result from reducing ozone concentrationsto natural “background’ levels. Similar estimatesof the effects of acid deposition on crops, or of theeffects of pollutant mixes, are not yet possible.

Data from field experiments were used to esti-mate ozone effects on crop productivity for peanuts(a sensitive crop), soybeans (sensitive/intermediate),wheat (intermediate), and corn (tolerant). These‘‘dose-response’ relationships were then combinedwith 1978 ozone monitoring data and 1978 agri-cultural statistics. Results suggest that if ozone con-

zThis section is based primarily on material from: Oak R idgc N a-tional Laboratory, Environmental Sciences 13i\”ision, ‘ ‘An Anal?’slsof Potential Agriculture and Forest Impacts of Long-Range Trans-port .Air Pollutants, contractor report submitted to the Offlce of Tech-nology Assessment, 1982.

centrations had been reduced to natural, back-ground levels in 1978, corn yields would haveincreased by 2 percent, wheat by 5 percent, soy-beans by 13 percent, and peanuts by 24 percent.As measured by 1978 crop prices, ozone causedabout a 6- to 7-percent loss of agricultural produc-tivity, of which almost two-thirds stemmed fromsoybean losses.

In forest ecosystems, transported pollutants maydirectly damage trees, as well as affect the soils inwhich trees grow. Because trees are long-livedspecies, they are vulnerable to long-term chroniceffects. Scientists have documented ozone damageto the foliage of many tree species, but the concen-trations of ozone necessary to cause damage is notwell known. About one-quarter to one-third of theforested land area in the Eastern United States isexposed to ozone concentrations about twice thenatural background levels.

Concern over the effects of acid deposition andozone on forests stems from observed productivitydeclines and tree death in areas with elevated pol-lution levels. Pests or disease—common causes offorest declines—do not appear to be responsible fordamage in such areas as the Adirondack Moun-tains in New York, the White Mountains in Ver-mont, the Pine Barrens in New Jersey, the Shenan-doah Mountains in Virginia, the Smoky Mountainsin Tennessee, and forested areas of West Germany.Acid deposition, ozone, heavy-metal deposition,severe winters, drought, or a combination of theseare possible causes under investigation. Acid dep-osition might be a factor either by affecting treesdirectly or by altering the soils on which trees grow.

Acid deposition can remove essential nutrientssuch as calcium and magnesium directly from treefoliage. If the rate of nutrient loss is greater thancan be replaced through the roots, nutrient defi-

Ch. 3—Transported Air Pollutants: The Risks of Damage and the Risks of Control ● 4 5

Photo credit: Arthur Johnson

Dead and dying red spruce at Camel’s Hump in theGreen Mountains of Vermont. Tree death and growthdecline of red spruce in Northeastern forests haveled some researchers to speculate about potentiallinks between forest damage and acid deposition.Scientific investigations cannot yet confirm or rule

out acid deposition as a contributorto the observed damages

ciency will result. Scientists do not know which treespecies are most susceptible to foliar nutrient loss,or the level of acid deposition at which such lossbecomes harmful.

Forest soils may be altered by acid depositionwith either beneficial or harmful results. Thenitrates and sulfates from acid deposition can supplyessential plant nutrients. In many areas, nitrogenin the soil is in short supply; on these soils nitratesin acid rain might improve forest productivity. Sul-fur-deficient soils, however, are quite rare.

Nonacidic or weakly acidic soils typically con-tain such large quantities of neutralizing substances(e. g., calcium) that harmful changes to these soilsseem unlikely. Of greatest concern are forest eco-systems with naturally acidic soils. The major soil-mediated risks from acid deposition include:

1. mobilization of metals such as aluminum thatare toxic to plants in sufficient quantity, and

2. the potential stripping of calcium, magnesi-um, and other nutrients essential for plantgrowth from the soil.

Naturally acidic soils occur fairly extensively, be-ing the predominant soil type in about half thecounties east of the Rocky Mountains covered byforest or rangeland. In about one-third of theseacidic soils, the strong, freely moving acids fromacid deposition can release aluminum and othertoxic metals from the soil. However, whether tox-ic metals are released in sufficient quantities to af-fect forest productivity is unknown. The remain-ing two-thirds of Eastern acidic soils are underlainwith surface layers that can trap sulfate, possiblypreventing the release of aluminum in these areas.

Acid deposition can remove essential nutrientssuch as calcium and magnesium from the soil, butthe rate of removal-and the importance relativeto other factors—is difficult to determine. Moder-ately acid soils are thought to lose nutrients at afaster rate than more acid soils, but the more acidsoils typically have less nutrients. On nutrient-pooracid soils, especially those where sulfate can travelfreely through the soil, further nutrient loss—evenat a slow rate—from the soil, forest canopy, anddecomposing plant material might be significant.About 15 to 20 percent of the Eastern counties meetthese criteria, but whether nutrient loss is signifi-cant enough to affect near-term forest productivi-ty is unknown.

Though relatively rare in the Eastern UnitedStates, some moderately acid soils might furtheracidify from nutrient loss over decades of exposureto acid deposition. About 1 to 5 percent of theEastern counties (depending on the soil criteriaused) are dominated by soils of this type.

Data and knowledge limitations prevent a moredetailed description of the risks of transported airpollutants to forests than given above. Of concern


are forested lands exposed to: 1) high ozone con-centrations, 2) high levels of acid deposition, or3) underlain with soils that maybe sensitive to aciddeposition.

Other Resources

Air pollution damages a broad range of materi-als-including building stone, rubber, zinc, steel,and paint. Ozone is the pollutant that most affectsrubber, while many other materials are chiefly af-fected by sulfur oxides. Humidity plays a key rolein materials damage—dry-deposited sulfur dioxideand sulfate that dissolve on moist surfaces (form-ing concentrated sulfuric acid) may cause greaterdamage than relatively less acidic rain. Since airpollution is only one of many environmental fac-tors (e. g., temperature fluctuations, sunlight, salt,micro-organisms) that cause materials damage, itis difficult to determine what proportion of damageit accounts for. Moreover, it is difficult to deter-mine the proportion of materials damage causedby transported pollutants as opposed to local pollu-tion sources.

Analyses of the monetary costs of materials dam-age frequently make assumptions about the quan-tity of sensitive materials exposed to elevated pollu-tion levels and the effects of damage on replace-ment or repair rates. A recent EPA-funded studyemployed an alternative approach, using data onexpenditures in 24 metropolitan areas and 6 man-ufacturing sectors to estimate the extra materials-related costs attributable to sulfur pollution.3 It con-cluded that reducing sulfur dioxide emissions in ur-ban areas to meet concentrations about 25 to 30percent below the national primary standard wouldcreate benefits of approximately $300 million an-nually for about one-half the households and about5 to 10 percent of the producing sector in the UnitedStates. These results cannot be extrapolated to pro-vide estimates of benefits to the Nation overall, asthe lack of necessary data precludes analyzing therest of the economy in this manner.


Statues in a Kentucky cemetery illustrate one of thedifficulties in assessing pollution-related damages tomaterials. Acidic pollutants and natural weatheringhave helped erode both the covered and uncoveredmarble statues shown above. However, rainfall alsowashes away some of the dry-deposited pollutants

from the uncovered statue at right

Yet another resource at risk from transported airpollutants is visibility.4 Visibility levels depend ona number of factors, including humidity, manmadepollutant emissions, and such other factors as fog,dust, sea spray, volcanic emissions, and forest fires.

Pollutants impair visibility by scattering and ab-sorbing light. Concentrations of fine particles-pri-marily sulfates and nitrates—can sufficiently inter-

3E. H. Manuel, Jr., et al., “Benefits Analysis of Alternative Sec-ondary National Ambient Air Quality Standards for Sulfur Dioxideand Total Suspended Particulate, Mathtech, Inc., report submit-ted to the U.S. EnvironmentaJ Protection Agency, OAQPS, 1982.

‘This subsection is based primarily on: B. L. Niemann, ‘‘Reviewof the Long-Range Transport of Sulfate Contribution to RegionalVisibility Impairment, contractor report submitted to the Office ofTechnolog y Assessment, 1983.

Ch. 3—Transported Air Pollutants: The Risks of Damage and the Risks of Control 47

fere with the transmission of light to reduce visibilitylevels significantly. Elevated levels of these andother particles in the atmosphere periodically createregional haze conditions, reducing contrast, distort-ing nearby objects and causing distant ones to dis-appear, discoloring the atmosphere, and decreas-ing the number of stars visible in the night sky. Ex-amination of airport data, pollution measurements,and satellite photography also indicates that region-al-scale hazy air masses move across large geo-graphic areas, and cause significant visibility reduc-tion in areas with little or no air pollutant emis-sions. Episodic haze conditions during summer cur-rently make it the worst season for visibility.

Sulfate concentrations correlate well with visibili-ty impairment over large regions of the UnitedStates; in the East, sulfate appears to be the singlemost important contributor to visibility degrada-tion. Recent studies suggest that sulfates accountfor 70 percent of visibility impairment during thesummer, and 50 percent annually, in the EasternUnited States. Nitrates rarely contribute substan-tially to visibility degradation in the East. However,in the Western United States, windblown dust andnitrogen oxides can also reduce visibility signifi-cantly.

Risks of Health Effects5

Extremely small particles, including airborne sul-fates, are the component of transported air pollut-ants of greatest concern for human health. Thesesmall particles can travel long distances through theatmosphere and penetrate deeply into the lung ifinhaled. Statistical (cross-sectional) studies of deathrates throughout the United States have found somecorrelation between elevated mortality levels andelevated ambient sulfate levels. Whether sulfate isactually linked to premature mortality, or merelyindicates other harmful agents (e. g., other partic-ulate) associated with sulfates, is unknown.

To estimate damages caused by transported airpollution quantitatively, OTA used sulfate concen-trations as an index of this ‘‘sulfate/particulatem i x . The analysis projected a range of mortality

5Thls section is based primarily on: Brookhaven NationalI.aboratory, Biomedical and Environmental Assessment Division,‘‘ I.onq-Range Transport Air Pollution Health Effects, contractorreport subm ]tted to the Office of Technology Assessment, 1982.

●

Photo credit: John Skelly

View of the Peaks of Otter in the Shenandoah NationalPark under different visibility conditions. The picture attop was taken on a relatively pollution-free day; thepicture on the bottom shows the same scene when a

regional-scale hazy air mass obscures the view

estimates for a given population exposure level, inorder to incorporate disagreements within the scien-tific community over the significance of sulfates tohuman health. While some researchers concludethere is a negligible effect, others have found a sig-nificant association, ranging up to 5 percent of thedeaths per year in the United States and Canadaattributed to current airborne sulfate/particulatepollution. Though further research and data areneeded to resolve this controversy, this pollutantmix could be responsible for about 50,000 prema-ture deaths per year (about 2 percent of annualmortality), particularly among people with preex-isting respiratory or cardiac problems. If pollutantemissions remained the same through the year2000, increases in population might cause slightlyhigher numbers of premature deaths; a 30-percentdecrease in emission levels by 2000 might reducethe percentage of deaths annually attributable toair pollution to 1.6 percent (40,000 persons). Ineach of these cases, ranges of mortality are es-timated to extend from zero deaths to about threetimes the number reported above.


Researchers have not found consistent associa-tions between health effects and outdoor concen-trations of nitrogen oxides. High localized concen-trations of nitrogen dioxide are considered greatercause for concern than ambient levels of trans-formed and transported nitrogen oxide pollutants.However, quantitative estimates of health-relateddamages due to nitrogen oxides, or of the popula-tions at risk from these pollutants, cannot yet bedeveloped.

Acidified waters can dissolve such metals asaluminum, copper, lead, and mercury, and releasesuch toxic substances as asbestos, from pipes andconduits in drinking water distribution systems aswell as from soils and rocks in watersheds. Watersamples from some areas receiving high levels ofacid deposition show elevated metal concentrations,raising concern about a possible connection betweenacid deposition and degradation of drinking waterquality. Drinking water samples in the Adirondackshave shown lead concentrations of up to 100 timeshealth-based water quality standards. Mercury con-centrations above public health standards have beenfound in fish from acidified lakes in Minnesota,Wisconsin, and New York. Elevated levels of alu-minum and copper, two metals not considered toxicto the general public, have also been found bothin Adirondack well water and in surface water sam-ples throughout New England. Acidified munici-pal water supplies can be monitored and correctedquite easily. However, acidified well water in ru-ral areas is more difficult to detect and mitigate.Potential health effects due to acidification of thesewater supplies and subsequent leaching of toxicsubstances remain of concern.

Potential for the Courts or EPATo Rule in the Absence ofCongressional Direction6

The existing Clean Air Act does not directly ad-dress long-range pollution transport; however, pro-visions added to the Act during a previous reauth-orization (1977) require States and EPA to ensurethat stationary sources of pollution in any givenState do not prevent attainment of air quality stand-

‘This section is based primarily on material from: ‘ ‘Avenues forControlling Interstate Pollution Under the Current Clean Air Act,the Office of Technology Assessment staff paper, 1982.

ards in another State. These provisions are wordedvery generally; the act contains no procedures orguidelines for determining how interstate pollutioneffects are to be measured, or what levels of in-terstate transport are impermissible.

A number of States have sought to use these in-terstate pollution provisions as a vehicle for com-pelling other States to curb emissions of transportedpollutants. These States have challenged EPA-approved pollution control plans in court, and havepetitioned EPA to require reductions in cumulativeemissions from upwind States in order to abatepresent levels of interstate pollution. EPA has madeno determinations on petitions requesting relieffrom long-range pollution effects; however, in legalproceedings the Agency has taken the position thatno reliable analytic tools are currently available toassess long-range pollution transport. Affected par-ties are likely to challenge any future EPA deter-mination on these petitions in court; thus, in theabsence of further congressional action, the judicialbranch could ultimately be required to arbitrate thelong-range transport controversy.

Risk of StrainedInternational Relations7

Present Federal policies on transported pollutantshave also strained relations between the UnitedStates and Canada. Bilateral efforts are proceedingunder a Memorandum of Intent (MOI) to developan accord on the acid deposition issue. However,the Canadian Government has not been pleased bythe progress of these negotiations. A dissatisfiedCanada could choose to link the acid rain issue toother important areas of bilateral concern. TheClean Air Act currently provides Canada no ex-plicit means of legal recourse for abating long-rangetransported air pollution from the United States.However, the previous administration took actionsunder the international provision of the Clean AirAct that may have created a legal obligation for thiscountry to reduce emissions.

7This section is based primarily on material from: EnvironmentalLaw Institute, “Long-Range Air Pollution Across National Bound-aries: Recourses in Law and Policy, contractor report submitted tothe Office of Technology Assessment, 1981.


IF FURTHER EMISSIONSREDUCTIONS ARE MANDATED

Of the major transported pollutants, congres-sional attention has focused on controlling aciddeposition. Acid deposition results from both sulfurand nitrogen oxides; however, in the EasternUnited States, sulfur oxides currently contributeabout twice as much acidity as nitrogen oxides.Several bills proposed during the 97th and 98thCongresses would mandate reducing sulfur diox-ide emissions by about one-third to one-half eitherthroughout the continental United States or in the31 States bordering and east of the MississippiRiver.

Of the 26 to 27 million tons of sulfur dioxideemitted in the United States during 1980, about22 million tons were emitted in the Eastern 31States. Electric utilities emitted about 70 to 75 per-cent of the total eastern, approximately 16 milliontons. Non-utility combustion (primarily industrialboilers) accounted for about 10 to 15 percent of thetotal, with the remainder coming from industrialprocesses and other sources. Each of three States—Ohio, Pennsylvania, and Indiana—emitted in ex-cess of 2 million tons of sulfur dioxide per year,totaling 30 percent of the region’s emissions. Sixadditional States— Illinois, Missouri, Kentucky,Florida, West Virginia, and Tennessee—emittedin excess of 1 million tons each, together produc-ing an additional 30 percent of the 3 1-State total.

Most current legislative proposals would placethe greatest burden of emissions reductions on theutility sector and the Midwestern States. The costslikely to result from a control program include:

1.2.

3.

increased electricity costs to consumers,loss of coal production and subsequent unem-ployment in regions where high-sulfur coal ismined, andfinancial strain to certain vulnerable utilitiesand industrial corporations.

The risk imposed by a control program is thatsome of these costs might be unnecessary. A con-trol program designed 10 years hence might achievethe same level of protection at lower cost than onedesigned today; similarly, the level of required pro-

tection might be more accurately identified. Thissection first presents the potential costs of control,and then discusses the risk that the control programmight not be as efficient or cost effective as desired.

Utility Control Costs

Both the total tonnage of sulfur dioxide to beeliminated, and control costs per ton, determinethe cost of controlling utility sulfur dioxide emis-sions. Costs rise as greater removal is sought, bothbecause more emissions are being controlled andbecause the cost of eliminating each additional tonof sulfur dioxide increases. OTA estimates the costsof reducing sulfur dioxide emissions in the 31 East-ern States, in 1982 dollars, to be about:

●

●

●

●

●

●

$0.5 to $1 billion/year to eliminate about 4 to5 million tons/year$1 to $2 billion/year to eliminate about 6 to7 million tons/year$2 to $2.5 billion/year to eliminate about 8 mil-lion tons/year$2.5 to $3.5 billion/year to eliminate about 9million tons/year$3 to $4 billion/year to eliminate about 10 mil-lion tons/year$4 to $5 billion/year to eliminate about 11 mil-lion tons/year

The estimates above are based on the costs ofcontrolling utility emissions, and do not includecosts to offset any future emissions increases fromutilities and industry. These costs can also be pre-sented as percent increases in average residentialrates for electricity, on both a regional and Statebasis. For example, a 50-percent reduction in utilitysulfur dioxide emissions (8 million tons per year,about 35 percent below total regional emissions)would increase average residential rates by about2 to 3 percent. Rate increases would vary by State,of course—consumers in some States would pay noincreases, while others would pay over twice theregional average. For specific utilities, costs maybe somewhat higher—several utilities have asserted


that their residential rates might increase by 25 per-cent or more. 8

These cost estimates are for control strategies thatlimit rates of emissions— sulfur dioxide emitted perquantity of fuel burned—similar to provisions inseveral bills proposed during the 97th and 98thCongresses. The range of cost estimates for eachreduction level presented above reflects alternativemethods of allocating emissions reductions withina State. In addition, the estimates assume that eachutility chooses the most cost-effective method ap-plicable to plant conditions. This results in a mixof scrubber use and fuel switching throughout theregion.

The cost of removing a ton of sulfur dioxide isgenerally lower when a plant’s emission rate is high.Consequently, total regional control costs are lowerwhen emissions cutbacks are allocated to States onthe basis of their emissions rates than when equalpercentage reductions are required for all States.As discussed in chapters 6 and 7, this method ofallocating reductions concentrates a higher propor-tion of reductions on Midwestern States whose util-ities burn high-sulfur coal. However, many areasthat currently have lower sulfur dioxide emissionsrates already pay higher electricity costs than prevailin the Midwest.

Effects on the U.S. Coal Market

Switching from high- to low-sulfur coal is oneof the major available options for achieving substan-tial emissions reductions. Consequently, mandatingfurther emissions reductions creates the risk ofsignificant coal-market disruptions by increasingthe demand for low-sulfur coals at the expense ofhigh-sulfur coals. Risks of production and employ-ment losses occur almost exclusively in the EasternUnited States, where coal reserves are primarilyof high-sulfur content. The Western coal-producingStates, and parts of Kentucky and West Virginia,contain low-sulfur coal reserves and might thereforebenefit from acid deposition controls. For the na-tion as a whole, regulations designed to control acid

8’ ‘A Report on the Results From the Edison Electric Institute Studyof the Impact of the Senate Committee on Environment and PublicWorks Bill on Acid Rain Legislation (S. 768), ” National EconomicResearch Associates, Inc., report submitted to Edison Electric Institute,1983.

deposition would probably not affect total coal pro-duction.

The extent to which utility and industrial userswould shift to low-sulfur coal depends on therelative cost advantage of fuel switching as opposedto removing sulfur dioxide by technological means(e.g., scrubbers). Each method has clear advantagesfor some situations, but for many plants, the costdifference is modest enough to make predictionsof future preferences highly uncertain. The follow-ing projections of future coal production and em-ployment shifts are based on current costs, andmight change significantly if new control technol-ogies become available or coal prices change.

OTA estimated the extent to which coal produc-tion and employment would be affected by an emis-sions reduction program of 10 million tons or morethat neither mandates nor provides financial incen-tives for using particular control technologies.Under such a program, 1990 levels of productionin the high-sulfur coal areas of the Midwest (Illinois,Indiana, and western Kentucky) and Northern Ap-palachia (Pennsylvania, Ohio, and northern WestVirginia) might decline to about 10 to 20 percentbelow 1979 levels. Estimates of production declinesare averaged over these regions, and thus may begreater or less in some States and counties thanothers.

For the low-sulfur coal areas of Central Appala-chia (eastern Kentucky, southern West Virginia,Tennessee, and Virginia) and the Western UnitedStates, acid rain control measures are projected toexpand coal production beyond currently projected1990 levels. This effect is more pronounced in Cen-tral Appalachia than in the West, due to its prox-imity to Eastern markets.

In general, employment changes would followchanges in production. A 10-million-ton emissionscutback is projected to reduce employment in high-sulfur coal-producing areas by between 20,000 and30,000 jobs from projected 1990 levels. About15,000 to 22,000 additional jobs would open up inEastern low-sulfur coal-producing areas, and an ad-ditional 5,000 to 7,000 jobs in the West. The riskof unemployment is most severe in Illinois, Ohio,northern West Virginia, and western Kentucky—for these areas, coal-mining employment is pro-jected to decline more than 10 percent below cur-rent levels.


Photo cred i t : Douglas Yarrow

Last shift comes out at Eccles #5 before the 1977 contract strike

These employment shifts would cause propor-tional changes in direct miner income. At the na-tional level, benefits to low-sulfur regions are pro-jected to balance out losses to high-sulfur regions.This level of aggregation, however, obscures theregional distribution of coal-related economic costs.Direct income effects for a 10-million-ton emissionsreduction are estimated below:

● Northern Appalachia: $250 to $350 million peryear loss;

● Central Appalachia: $400 to $550 million peryear gain;

● Midwest: $250 to $400 million per year loss;● West: $100 to $200 million per year gain.

The total economic impacts of coal-market shifts—reflecting, in addition, indirect employment andincome effects on other economic activities—maybe two to three times greater.

Effects on Utility andIndustrial Financial Health

While the costs of further controlling utility sulfuremissions are ultimately passed on to electricity con-sumers, they can strain the resources of financial-ly troubled utilities that must initially pay them.Additionally, reducing industrial process and boileremissions imposes the risk of rendering sulfur di-oxide-emitting industries in controlled regions less


competitive than their less or uncontrolled counter-parts in other geographic areas.

On the basis of average 1980 utility bond ratingsand stock indicators, utility sectors in eight Statesappeared to be relatively vulnerable to the addi-tional capital requirements that could result fromfurther sulfur dioxide control: Arkansas, Connect-icut, Florida, Maine, Michigan, Pennsylvania,Vermont, and Virginia. * If cutbacks are allocatedon the basis of emissions rates, three of theseStates—Pennsylvania, Florida, and Michigan—are likely to be required to reduce emissions sig-nificantly. Greatest reductions would be requiredin Pennsylvania, where present State regulatorypolicies also cause substantial delays before utilitiescan pass increased fuel costs and/or constructioncosts on to consumers.

Several other States have regulatory policies con-sidered unfavorable to utility pollution control ex-penditures, although their utilities showed betteraverage financial health in 1980. The regulatorypolicies set by public utility commissions in eachState can significantly affect the financial burdenof raising additional capital to further control sulfurdioxide emissions. Such policies vary substantial-ly from State to State. Moreover, these policies aresubject to change, and might themselves be affectedby the passage of new pollution control legislation.

Major increases in electricity costs due to in-creased controls might also hurt utilities by reduc-

‘Individual utilities in relatively weak financial conditions were alsofound in Massachusetts, Indiana, Ohio, Georgia, New Jersey, andWest Virginia.

ing demand for electricity. However, OTA-pro-jected increases in average electricity rates resultingfrom stricter sulfur dioxide emissions controls arenot high enough to affect demand for electricalpower appreciably.

OTA also identified industries in which electricityis a major component of production costs. Forabout 15 industries, concentrated primarily in theareas of primary metals, chemicals and allied prod-ucts, and stone, clay, and glass products, electrici-ty costs exceed 10 percent of the value added* bythe manufacturer—nearly four times the nationalaverage. Electricity costs are equal to about 40 per-cent or more of the value added in industries thatproduce electrometallurgical products, primaryzinc, primary aluminum, alkali- and chlorine-basedchemicals, and industrial gases—these five indus-tries alone use about 16 percent of the electricityconsumed by industry in this country. Within theseenergy-intensive industries, manufacturers servedby utilities with high control costs might be ren-dered less competitive than those in regions thatare either uncontrolled or incur lower control costs.

Preliminary analyses of industrial process emis-sions also suggest some potential for economic dis-location in the iron and steel and cement industriesif their emissions were to be strictly controlled.Stricter sulfur dioxide emissions controls, if imposedin the Southwestern United States, could also createhardships for the region’s currently depressed cop-per smelting industry.

● ’ ‘Value added” is the difference between the selling price of theproduct and the cost of energy and materials to manufacture it.

RISK THAT CONTROL MAY NOT BE ASEFFECTIVE OR EFFICIENT AS DESIRED

Proposals for controlling sulfur dioxide emissionsaim to reduce sulfur deposition—a major contribu-tion to acidification—in areas sensitive to its effects.However, as discussed previously, incomplete un-derstanding of pollutant transport and transforma-tion creates the risk that any control strategy de-signed at this time: 1) will not reduce depositionto the extent, and in the specific locations, desired;and 2) may not be as cost-effective as possible.

This section reviews estimates of the reductionin acid deposition needed to minimize further dam-age to sensitive resources—and the likelihood ofreaching these “deposition targets” under alter-native control strategies. In addition, the sectiondiscusses the potential for designing a more cost-effective strategy to reduce acid deposition by con-trolling nonsulfur pollutants in addition to sulfurdioxide.

Ch. 3—Transported Air Pollutants: The Risks of Damage and the Risks of Control ● 53

Effectiveness of EmissionsReductions for Achieving Desired

Deposition Reductions

While any major reduction in acid depositionlevels would likely benefit some sensitive resources,scientists have attempted to define ‘ ‘target’ deposi-tion levels—the maximum level of deposition foravoiding further damage to all but the most sensi-tive resources. * Target deposition values have beenpresented in reports by the National Academy ofSciences (NAS), the Impact Assessment WorkGroup established by the United States-CanadaMemorandum of Intent on Transboundary AirPollution, * * a working group at the 1982 Stock-holm Conference on the Acidification of the Envi-ronment, and others. These have been expressedas levels of acidity, levels of sulfate in rainfall, ortotal deposited sulfur.

OTA estimated the reductions in ‘ ‘wet sulfurdeposition’ —the sulfur deposited in rain andsnow—necessary to reach these target depositionlevels. As outlined in chapter 5 and appendix C,the estimates range from eliminating about 50 to80 percent of deposition in those areas receivinghighest levels, to eliminating about 20 to 50 per-cent of deposition over large regions of EasternNorth America identified as having sensitiveaquatic resources.

Several bills introduced during the 97th and 98thCongresses proposed cutting sulfur dioxide emis-sions back by about 8 to 10 million tons per year—about a 35 to 45 percent reduction in Eastern U.S.emissions. Using two different types of computermodels, OTA estimated the sulfur deposition re-ductions that might result if these legislative pro-posals were enacted. The more optimistic modelestimate suggests that both wet and dry sulfur depo-sition would be reduced by as much as 45 to 60percent in the areas of greatest deposition. Both wetand dry sulfur deposition would be reduced byabout 30 to 50 percent annually over large regions

● Maximum deposition targets are based on protecting aquaticresources, as too little is known about the sensitivity of other resourcesto allow similar levels of protection to be defined. In addition, mosttargets are based on amounts of wet deposition, since current dataare insufficient for considering dry deposition.

● ● Only the Canadian members of the Work Group recommendeda target deposition value.

of Eastern North America. The second model pro-jection—based on conditions that prevail during ex-treme pollution episodes—suggests that emissionsreductions of 35 to 45 percent would comparablyreduce dry sulfur deposition. However, the modelpredicts that wet sulfur deposition would respondless directly, decreasing by about 25 to 35 percentin areas of greatest deposition, and by 20 to 30 per-cent over much of Eastern North America, duringhigh pollution episodes. g

These estimates provide a plausible range of dep-osition reductions that might result from reducingemissions by 35 to 45 percent. The reductions intotal sulfur deposition estimated above are difficultto compare to target deposition levels, because thesetargets have been expressed in a variety of ways.However, the following preliminary conclusions canbe drawn, subject to a large degree of uncertainty:In areas of greatest deposition, for example, west-ern Pennsylvania, reducing Eastern United Statessulfur dioxide emissions by 8 to 10 million tons peryear might not be sufficient to bring depositionlevels within the targeted maximum for protectingall but the most sensitive resources. In areas receiv-ing less deposition, such as northern New England,the southern Appalachians, and the upper Midwest,sulfur dioxide emissions reductions of this magni-tude are likely to achieve the target depositionlevels.

Efficiency Concerns

Because large-scale cutbacks in sulfur dioxideemissions will cost billions of dollars annually, somehave suggested that even if the deposition reduc-tion goals could be achieved now, a more cost-effective program might be designed when atmos-pheric processes are better understood, Such con-cerns raise the following questions:

1, Can specific sources or source areas affectingsensitive resource areas be identified for emis-sions control?

‘A recent NRC study for the National Academy of Sciences usedslightly modified model assumptions to reexamine the OTA analysis.The NRC committee concluded that reductions in wet sulfur deposi-tion would more closely approximate the reductions in sulfur dioxideemissions than OTA had estimated. Acid Deposition: AtmosphericProcesses in Eastern North America, Committee on AtmosphericTransport and Chemical Transformation in Acid Deposition, NationalResearch Council, National Academy Press, Washington, DC., 1983.


2. Can cutbacks in other acidifying pollutants,such as nitrogen oxides, eliminate acid deposi-tion for lower cost?

3. Can sulfur deposition be controlled more costeffectively by controlling co-pollutants such asreactive hydrocarbons concurrently with sul-fur dioxide emissions?

Atmospheric transport models for linking sourceregions and receptor regions have been availablefor several years, but their accuracy is subject todebate, Current understanding suggests that, giventhe widespread distribution of sensitive resources,a program to bring deposition within the previous-ly mentioned target rates in all sensitive areas wouldhave to encompass most of the Eastern UnitedStates. Within some bounds, emissions reductionsfrom one area can be substituted for reductionsfrom another without jeopardizing the desired pat-tern of deposition, but the goal of minimizing totalcosts is likely to conflict with cost distribution goals.The dual problems of defining the value of one re-source area relative to others, and equitably dis-tributing costs, are difficult political questions thatcould not be solved through more accurate model-ing capabilities.

Controlling nitrogen oxides may be less expen-sive for some sources than controlling sulfur ox-

ides, but whether it is as efficient for preventingresource damage is subject to question. Current-ly, twice as much rainfall acidity comes from sulfuroxides as from nitrogen oxides. In addition, plantsoften take up nitrogen oxides as nutrients, furtherincreasing the proportion of lake and stream acidityproduced by sulfur oxides. Though future researchmay reveal that intermittent events—such as springsnow melts containing high levels of both depositednitrogen oxides and sulfur oxides—are responsiblefor the greatest share of damage, current under-standing suggests that sulfur oxides are the firstchoice for control.

Future research may reveal more cost-effectiveopportunities for reducing sulfur deposition by con-trolling co-pollutants concurrently with sulfur diox-ide emissions. Preliminary modeling results indicatethat the ratio of reactive hydrocarbons to nitrogenoxides is an important determinant of the atmos-pheric transformation of sulfur oxides. Thoughbroad regional sulfur oxide deposition overall mightremain relatively constant, reducing emissions ofthese co-pollutants along with sulfur dioxide mightachieve more desirable patterns of deposition thanwould result from reducing sulfur dioxide emissionsalone.

Chapter 4

The Pollutants of Concern

Contents

Page

Emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57Current and Historical. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57Future Emissions Under Current Laws and Regulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Patterns of Pollutant Emissions, Air Concentrations, and Deposition . . . . . . . . . . . . . . 63Geographical Emissions Patterns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63Geographical Patterns of Deposition and Air Concentrations for

Transformed Pollutants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

The Regional Patterns of Sulfur Oxides Transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

TABLES

Table No. Page

1. 1980 Total Emissions of Sulfur Dioxide, Nitrogen Oxides, andHydrocarbons in the United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

2. Historical Trends in Sulfur Dioxide, Nitrogen Oxides, and Hydrocarbon Emissions . . . . 583. Projected Sulfur Dioxide Emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 604. Projected Nitrogen Dioxide Emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

FIGURES

Figure No. Page

11. Forecasts of Utility Sulfur Dioxide Emissions for the Eastern 31-State Regionof the United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

12. Sulfur Dioxide Emissions Density . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6413. Nitrogen Oxide Emissions Density . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6514. Hydrocarbon Emissions Density . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6515. Precipitation Acidity—Annual Average pH for 1980,

Weighted by Precipitation Amount . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6616. Annual Sulfate Ion Deposition in Precipitation for 1980,

Weighted by Precipitation Amount . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6717. Airborne Sulfate—Annual Average Concentration for 1977-78. . . . . . . . . . . . . . . . . . . . . . 6818. Ozone Concentration-Daytime, Growing Season Average for 1978. . . . . . . . . . . . . . . . . 6919. The Effects of Time and Distance on Conversion and Deposition of Sulfur Pollution . . 7020. 1979 Sulfur Dioxide Emissions and Estimated Sulfur Deposition—

Percent Contributed and Received in Four Subregions Covering the Eastern Halfof the United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

21. Percent of Sulfur Deposition Estimated To Originate From Within Each Region andFrom Other Regions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

22. Estimated Percentage of Sulfur Deposition From Emissions Over 500 km Away . . . . . . 74

Chapter 4

The Pollutants of Concern

This chapter: 1) provides estimates of pollutantemissions, 2) describes current geographic patternsof emitted pollutants, and concentrations anddeposition of transformed pollutants, and 3)analyzes the patterns and processes of pollutanttransport and transformation. The pollutants ofconcern and their transformation products are:

●

●

●

sulfur dioxide—both as sulfur dioxide gas andas the transformation product, sulfate;nitrogen oxides—as a gas, as the transforma-tion product, nitrate, and as a precursor ofozone; andreactive hydrocarbons—as precursors ofozone.

OTA has assembled estimates of current emis-sions and historical and projected emissions trendsfor these three pollutants. Projections of sulfur di-oxide and nitrogen oxides emissions are providedfor the United States overall, for the Eastern 31-State region, and by major producing sector. The

chapter examines future utility emissions of sulfurdioxide in greater detail.

To show where these emissions originate, cur-rent emissions levels are described in a series ofmaps. The chapter then presents maps of measureddeposition levels for acidity and sulfate, and air con-centrations for ozone and airborne sulfate. Thesemaps can be used to compare the origins of thethree emitted pollutants to the eventual destinationsof the transformed pollutants on which the assess-ment focuses.

Finally, the chapter presents model-based esti-mates of the regional transport of sulfur oxides—the most abundant acid-producing pollutant, andthe pollutant for which the greatest amount of in-formation about transport, transformation, anddeposition patterns is available. In addition, the sec-tion briefly describes the chemical processes thattransform the three emitted pollutants, to aid in un-derstanding how changes in emissions levels mightaffect resulting levels of transported pollutants.

EMISSIONS

Current and Historical

In the United States during 1980 approximately26 million tons of sulfur dioxide, 21 million tonsof nitrogen oxides, and about 24 to 28 million tonsof hydrocarbons (volatile organic carbon) wereemitted by manmade sources. Of this total, about22 million tons of sulfur dioxide, 14 million tonsof nitrogen oxides, and about 19 to 20 million tonsof hydrocarbons were emitted in the 31 States eastof or bordering the Mississippi River. For the Na-tion overall, the major sources of sulfur dioxideemissions—about 90 to 95 percent of the total—are electric-generating utilities, industrial boilers,and industrial processes. Similarly, three sectors—utilities, mobile sources, and industry-producemore than 95 percent of the country’s manmadenitrogen oxides emissions. Mobile sources and in-dustrial processes produce about 80 to 85 percent

of U.S. hydrocarbon emissions, while the re-mainder comes from a wide variety of sources.

Table 1 presents current (1980) estimated emis-sions of sulfur dioxide, nitrogen oxides, and hydro-carbons for each of the 50 States. 1 To place the cur-rent level of emissions into historical perspective,table 2 shows estimated total U.S. and Eastern3 l-State emissions of sulfur dioxide and nitrogenoxides, and estimated total U.S. hydrocarbon emis-sions, for selected years between 1940 and 1980.Between 1940 and 1970, nationwide sulfur diox-ide emissions increased by roughly 50 percent, fromabout 19 million to 30 million tons per year. From

‘Estimates are from Emissions, Costs, and Enq”neering Assessment,Work Group 3B, United States-Canada Memorandum of Intent onTransboundary Air Pollution, June 15, 1982. Tables 3 and 4 com-pare the 50-State and Eastern 31 -State region totals, by utility andindustrial sector, with other estimates of sulfur dioxide and nitrogenoxides emissions.

57


Table 1 .—1980 Total Emissions of Sulfur Dioxide, Nitrogen Oxides, and Hydrocarbons in the United States(1,000 tons/year)

State S0 2 NO x HC State S0 2 NO X HC

Alabama . . . . . . . . . . . . . . . . . . . . . .Alaska. . . . . . . . . . . . . . . . . . . . . . . .Arizona . . . . . . . . . . . . . . . . . . . . . . .Arkansas . . . . . . . . . . . . . . . . . . . . .California . . . . . . . . . . . . . . . . . . . . .Colorado . . . . . . . . . . . . . . . . . . . . .Connecticut . . . . . . . . . . . . . . . . . . .Delaware . . . . . . . . . . . . . . . . . . . . .District of Columbia. . . . . . . . . . . .Florida . . . . . . . . . . . . . . . . . . . . . . .Georgia. . . . . . . . . . . . . . . . . . . . . . .Hawaii . . . . . . . . . . . . . . . . . . . . . . .Idaho . . . . . . . . . . . . . . . . . . . . . . . . .Illinois . . . . . . . . . . . . . . . . . . . . . . .Indiana . . . . . . . . . . . . . . . . . . . . . . .Iowa . . . . . . . . . . . . . . . . . . . . . . . . .Kansas . . . . . . . . . . . . . . . . . . . . . . .Kentucky . . . . . . . . . . . . . . . . . . . . .Louisiana . . . . . . . . . . . . . . . . . . . . .Maine . . . . . . . . . . . . . . . . . . . . . . . .Maryland . . . . . . . . . . . . . . . . . . . . .Massachusetts . . . . . . . . . . . . . . . .Michigan . . . . . . . . . . . . . . . . . . . . .Minnesota . . . . . . . . . . . . . . . . . . . .Mississippi . . . . . . . . . . . . . . . . . . .Missouri . . . . . . . . . . . . . . . . . . . . . .

76020

100445130

70110

151,100

8406050

1,4702,000

330220

1,120300100340340900260280

1,300

45055

260220

1,220275135

5020

650490

4580

1,000770320440530930

60250250690370280570

53050

250270

2,550360370

7035

880580

75170

1,200700300350430790120370600

1,100500330690

Montana . . . . . . . . . . . . . . . . . . . . . . 160Nebraska . . . . . . . . . . . . . . . . . . . . . 75Nevada . . . . . . . . . . . . . . . . . . . . . . . 240New Hampshire . . . . . . . . . . . . . . . 90New Jersey . . . . . . . . . . . . . . . . . . . 280New Mexico . . . . . . . . . . . . . . . . . . 270New York . . . . . . . . . . . . . . . . . . . . . 950North Carolina . . . . . . . . . . . . . . . . 600North Dakota . . . . . . . . . . . . . . . . . . 100Ohio . . . . . . . . . . . . . . . . . . . . . . . . . 2,650Oklahoma . . . . . . . . . . . . . . . . . . . . . 120Oregon . . . . . . . . . . . . . . . . . . . . . . . 60Pennsylvania ...,.... . . . . . . . . . . 2,020Rhode Island . . . . . . . . . . . . . . . . . . 15South Carolina . . . . . . . . . . . . . . . . 330South Dakota . . . . . . . . . . . . . . . . . 40Tennessee . . . . . . . . . . . . . . . . . . . . 1,100Texas . . . . . . . . . . . . . . . . . . . . . . . . 1,270Utah . . . . . . . . . . . . . . . . . . . . . . . . . 70Vermont . . . . . . . . . . . . . . . . . . . . . . 7Virginia . . . . . . . . . . . . . . . . . . . . . . . 360Washington . . . . . . . . . . . . . . . . . . . 270West Virginia . . . . . . . . . . . . . . . . . . 1,100Wisconsin . . . . . . . . . . . . . . . . . . . . 640Wyoming . . . . . . . . . . . . . . . . . . . . . 180

U.S. total . . . . . . . . . . . . . . . . . . . 26,500

1201908060

400290680540120

1,140520200

1,04040

20090

5202,540

19025

400290450420260

21,220

160200

70100810195

1,250680

701,280

460330

1,360120550110580

3,40016045

530500150530110

28,350SOURCE: Emissions,Costs and Engineering Assessment, Work Group 3B, United States–Canada Memorandum of lntent on Transboundary Air Pollution, June 15, 1982

Table 2.—Historical Trends in Sulfur Dioxide, Nitrogen Oxides, andHydrocarbon Emissions (millions of tons)

Sulfur dioxide Nitrogen oxides HydrocarbonsE a s t e r n Eastern

Year Nat iona lab 31 Statesb National a’h 31 Statesb National a

1940 . . . . . . . . . 19.1 — 7.2 — 15.31950 . . . . . . . . . 18.1-21.6 14.6 7.4-10.3 5.4 19.31955 . . . . . . . . . 17.7 14.3 8.5 6.4 –1960 . . . . . . . . . 21.2-22.2 18.9 11.5-14.0 8.5 23.81965 . . . . . . . . . 26.7 22.8 14.2 10.4 —1970 . . . . . . . . . 28.7-30.8 24.0 17,7-20.4 12.4 29.81975 . . . . . . . . . 27.3-28.2 23.4 19.3-21.6 13.3 25.11980 . . . . . . . . . 25.2-26.1 21.2 21.0-22.8 13.9 24.0-28.3C

SOURCES:National Air Pollution Emission Estimates, 1940-1980, U.S. Environmental Protection Agency, January 1982,EPA-450M-82-001.

—

“’Historic Emissions of Sulfur and Nitrogen Oxides in the United States from 1900 to 1980,” G. Gschwandtner,et al., 1980. Draft reports to EPA from Pacific Environmental Services, Inc.cEmissions Costs and Engineering Assessment, Work Group 3B, United States-Canada Memorandum of Intenton Transboundary Air Pollution, June 15, 1982

Ch. 4—The Pollutants of Concern ● 5 9

1970 to 1980 emissions totals show a decline fromabout 30 million to 26 million tons per year, andfrom about 24 million to 21 to 22 million tons forthe Eastern 31 -State region. Estimates are avail-ble for pre- 1940 emissions levels, but these arebased on incomplete data. These data suggest thatthroughout the period 19’20-40, nationwide sulfurdioxide emissions averaged roughly 17 million tonsper year.2 A ppendix A presents historical emissionsestimates in greater detail.

Over the period 1940-80, nitrogen oxides emis-sions grew much more rapidly than sulfur diox-ide—virtually tripling—but have declined slightlyfrom 1978 to 1980. Hydrocarbon emissions are es-timated to have doubled, from about 15 million tonsin 1940 to about 30 million tons per year in 1970.From 1970 to 1980, hydrocarbon emissions de-clined—according to various estimates, to about 24to 28 million tons per year.3

Future Emissions Under CurrentLaws and Regulations

Assuming that current air pollution laws and reg-ulations remain unchanged, future emissions ofboth sulfur dioxide and nitrogen oxides will dependprimarily on three factors:

● future demand for energy, including energyfor electricity generation, industrial fuel use,and automobiles;

● the type of energy used to meet future de-mand, for example, the extent of such non-fossil energy use as nuclear and hydropower,and less polluting fuels such as natural gas; and

● the rate at which existing pollution sources—both stationary sources and highway vehi-cles—are replaced with newer sources moretightly controlled under the Clean Air Act.

2“ Historic Emissions of Sulfur and Nitrogen Oxides in the UnitedStates From 1900 to 1980, ” G. Gschwandtner, et al., 1983. Draftreport to EPA from Pacific Envi ronmcntal Services, Inc.

‘ H ~drxx arbon cm isslons are d iff]( ult to est imatc, In part because

d major w)urc c of th(. ir product ion is the e~aporat ion of chemical

solt ents As shown in tables I And !2, the 24-m ll]ion - ton est imatc is

de ri~~d from U S F:nv ircrrrmentd Pt-otc( t ion Agen( y, .\’ariona/ ,4ir

P(dlu[an( Emiss]orr Estimates, 1940-1980, while the 28-mllllon-tonfrgure is from the U. S -Canada NI(II, Work Group 3B, Emissions,Costs and Enginet-rin<q .4ssevsmcnt.

Each of these factors is, of course, uncertain, butanalysts can estimate pollutant emissions that wouldresult from plausible future trends. The first threeparts of this section will present several projectionsof future sulfur dioxide, nitrogen oxides, and hy-drocarbon emissions over the next two to three dec-ades. The fourth part will discuss how these fac-tors, as well as further emission controls, affectfuture sulfur dioxide emissions from the utilitysector.

Sulfur Dioxide Emissions

Table 3 presents various projections of sulfur di-oxide emissions through the year 2010. For theUnited States as a whole, sulfur dioxide emissionsare projected to increase over 1980 levels by 10 to25 percent by 2000, and by 20 to 30 percent by2010. The greatest projected rate of increase is inthe industrial sector—25 to 40 percent by 2000.

Within the 31 Eastern States, the industrial sec-tor is again projected to account for the fastestgrowth in emissions. By 2000, total sulfur dioxideemissions are projected to increase by 10 to 30 per-cent, while emissions from the industrial sectoralone increase between 50 to 90 percent. By 2010,total emissions are projected to increase by about15 to 25 percent over 1980 levels. These projec-tions assume that rising oil and natural gas priceswill cause many current users of these cleaner fuelsto switch to coal. Utility emissions are forecast toincrease slightly through about 2000 and then tobegin declining slightly. Because of the growth in-crease projected for the industrial sector, utilityemissions will drop from about 75 percent of thetotal in 1980 to about 60 to 65 percent of the totalby 2010.

Nitrogen Oxides Emissions

While mobile sources are currently the singlelargest nitrogen oxides-producing sector, by 2010rapid growth in emissions from the utility sectoris expected to make utilities the single largest sourceof nitrogen oxides. Table 4 presents various pro-jections of nitrogen oxides emissions for utilities,mobile sources, and industry.

For the United States, nitrogen oxides emissionsby 2000 are expected to increase over 1980 levelsby about 25 percent; by 2010, emissions are forecast


Table 3.—Projected Sulfur Dioxide Emissions (million tons/year)

United States Eastern 31 States

1980 1985 1990 1995 2000 2005 2010 1980 1985 1990 1995 2000 2005 2010

Total: TotalMOI 1 . . . . . . . 26.5 – 25.3 – 29.3 – – MOI 1 . . . . . . . 21.8 – 21.4 – 24.3 – –EE1 2a . . . . . . . 27.3 26.9 27.2 29.4 31.1 – 33.4 EE12a . . . . . . . 21.7 21.2 21.6 23.5 23.9 – 24.6EE12b . . . . . . . 27.3 28.7 29.4 32.0 34.6 – 35.0 EE12b . . . . . . . 21.7 23.5 24.2 26.6 27.9 — 26.7

Utility: utility:MOI 1 . . . . . 17.3 – 17.5 — 17.9 — — MOI 1 . . . . . 16.0 – 15.9 — 16.1 — —EE1 2a . . . . . 17.5 17.6 17.9 18.6 18.2 — 18.2 EE12a . . . . . 16.2 1505 15.7 15.9 15.1 — 14.5EE1 2b . . . . . 17.5 19.3 20.1 21.2 21.6 – 19.8 EE12b 16.2 17.8 18.3 19.0 19.1 — 16.6EPA 3 . . . . . 17.4 18.8 20.0 20.2 19.6 — 18.7 EPA 3 : : : : : 16.2 17,1 17.9 18.0 17.1 — 15.8NWF 4 . . . . . – – 19.6 — 21.0 – – NWF 4 . . . . – – 17.8 — 18.1 — —

EEI 5 . . . . . . — — 18.3 – – — –

lndustry:?’:

Industry:MOI 1 . . . . 7.4 – 5.9 – 9.3 – – ? ’:MOI 1 . . . . . 4.4 – 4.1 – 6.7 – –EEI 2C . . . . . 7.5 7.4 7.2 8.6 10.5 – 12.2 EEI 2C . . . . . 3.8 4.2 4.4 6.3 7.2 — 8.2

EEI 5 . . . . . . — — 4.4 — — — —Sources of estimates:1. MOI—Emissions, Costs and Engineering Assessrnent, Work Group 3B, United States-Canada Memorandum of Intent on Transboundary Air Pollution, June 15, 1982.2. EEI—”Summary of Forecasted Emissions of Sulfur Dioxide and Nitrogen Oxides in the United States Over the 1980 to 2010 Period,” prepared by ICF Inc. and National

Economic Research Associates for the Edison Electric Institute and Utility Air Regulatory Group, April 1982.2a—National Economic Research Associates (NERA) estimate.2b—lCF Inc. estimate.2c—Joint NERA/ICF estimate.

3. EPA—Personal communication from J. Austin, EPA. Projections prepared for EPA by ICF Inc., using assumptions stated in “Analysis of a 10 Million Ton ReductionIn Emissions From Existing Utility Powerplants,” ICF Inc., June 1982.

4. NWF—’’Cost and Coal Production Effects of Reducing Utility Sulfur Dioxide Emissions,” prepared for National Wildlife Federation and National Clean Air Coalitionby ICF Inc., Nov. 14, 1981.

5. EEI—’’January 25, 1982 Preliminary ICF Analysis of the Mitchell Bill Prepared for the Edison Electric Institute, ” Edison Electric Institute letter, Feb. 8, 1982.

Table 4.—Projected Nitrogen Oxides Emissions (million tons/year)

United States Eastern 31 States

1980 1985 1990 1995 2000 2005 2010 1980 1985 1990 1995 2000 2005 2010

Total:MOI 1 . . . . . . . 21.2 – 21.2 – 26.6 –EEI2a . . . . . . . 21.0 22.2 22.3 23.9 26.2 –EEI2b . . . . . . . 21.0 21.7 22.3 24.0 26.5 –Utility:

MOI 1 . . . . . 6.4 – 7.5 – 9.6 –EEI 2a . . . . . 7.2 8.8 9.3 10.2 11.1 –EEI 2b . . . . . 7.2 8.3 9.3 10.3 11.4 –

Industry:? ’:MOI 1 . . . 4.6 – 4.2 – 5.6 –

EEI 2C . . . . . 3.5 3.7 4.2 4.7 5.3 –

Mobile:MOI 1 . . . . . 9.4 – 8.6 – 10.7 –EEI 2C . . . . . 9.4 8.9 8.2 8.4 9.2 –

—32.831.8

—14.813.8

—6.0

—11.5

Total:MOI 1 . . . . . . . 14.0 — 15,0 — 18.5EEI 2a . . . . . . . 14.9 15.6 15.6 16.4 17.7EEI 2b . . . . . . . 14.9 15.5 15.8 16.8 18.4

Utility:MOI 1 . . . . . 4.8 — 5.7 — 6.9EEI 2a . . . . . 5.4 6.5 6.8 7.2 7.6EEI2b 5.4 6.4 7.0 7.6 8.3EEI 3 . : : : : : – – 6.2 – –

Industry:1 :

MOI . . . . . 2.4 – 3.0 – 3.7EEI 2C . . . . . 2.3 2.5 2.8 3.2 3.7EEI 3 . . . . . . – – 2.6 – –

Mobile:MOl 1 ., . . . 6.2 — 5.8 — 7.3EEI 2C . . . . . 6.5 6.0 5.5 5.5 6.0

———

————

———

——

—21.821.3

9.99.4—

—4.1—

—7.4

Sources of estimates:1. MO1—Ern/ss/ems, Costs and Engineering Assessment, Work Group 3B, United States-Canada Memorandum of Intent on Transboundary Air Pollution, June 15, 1982.2. EEI—’’Summary of Forecasted Emissions of Sulfur Dioxide and Nitrogen Oxides in the United States Over the 1980 to 2010 Period,” prepared by ICF Inc. and National

Economic Research Associates for the Edison Electric Institute and Utility Air Regulatory Group, April 1982.2a—National Economic Research Associates (NERA) estimate.2b—lCF Inc. estimate.2c—Joint NERA/lCF estimate.

3. EEI—’’January 25, 1982 Preliminary ICF Analysis of the Mitchell Bill Prepared for the Edison Electric Institute, ” Edison Electric Institute letter, Feb. 8, 1982.


to increase by about 50 to 55 percent, The utilitysector is projected to account for most of this in-crease (about 60 to 75 percent). For the 31 EasternStates, nitrogen oxides emissions are projected toincrease by about 20 to 30 percent by 2000, andby about 45 percent by 2010.

Hydrocarbon Emissions

Reliable quantitative estimates of future hydro-carbon emissions are not available at this time.However, in general, hydrocarbon emissions areprojected to decline somewhat from 1980 levels, andthen to remain relatively constant. Petroleum refin-ing and storage is the only major source of hydro-carbons projected to significantly increase emissionsthrough 2000; expected improvements in abate-ment practices and potential shifts away from liq-uid hydrocarbon fuels toward coal use might par-tially or completely offset such increases.4 Emissionsfrom industrial processes—a major source of hy-drocarbons—depend heavily on the specific proc-ess in use, making these emissions very difficult toestimate.

Utility Sulfur Dioxide Emissionsin the 31 Eastern States

As demonstrated by the variations among theprojections presented in tables 3 and 4, forecastingpollutant emissions is not an exact science. Emis-sions scenarios depend on numerous assumptionsabout future economic conditions. For example,projections of rapid growth of sulfur dioxide emis-sions from the industrial sector assume increasedindustrial output, along with a change from oil useto coal. The range of the projections reflects dif-ferent plausible assumptions about future rates ofindustrial growth and the relative future price ofoil and coal.

OTA used a simple projection model to examinehow various factors affect forecasts of utility sulfurdioxide emissions in the Eastern half of the coun-try. The major factors affecting utility emissionsare: 1 ) demand for electricity (for this analysis,OTA assumes growth to be 2.5 percent per year,with a range of 2.0 to 3.0 percent per year); and2) retirement age of existing plants (for this analysis,

‘En \ironmenta/ Outlook f 980, L’. S. Environmental ProtectionAgency, July 1980, EPA-60018-80-003.

OTA assumes the useful life of a plant to be 50years, with a range of 40 to 60 years). Other fac-tors include reliance on nonfossil energy sources(assumed to provide the same proportion of elec-tricity generation as in 1980), emission rates fromnew sources regulated under the New Source Per-formance Standards (NSPS) (assumed to average0.6 lb sulfur dioxide per million Btu), and reduc-tions required to comply with State Implementa-tion Plans (SIPS) (assumed to be about 1 milliontons of sulfur dioxide; possible SIP relaxationsmight reduce this amount).

Figure 11 shows how these factors affect emissionsforecasts, using a 60-year forecast period to allowfor replacement of all utility plants operating in1980. Figure 11A illustrates the sensitivity of emis-sions forecasts to demand for electricity. The lowestcurve shows emissions in the unlikely event thatno growth in demand occurs. Under such a scenar-io, emissions would decline to 20 percent of the cur-rent 16 million tons of utility sulfur dioxide emis-sions when all existing sources are replaced by newsources regulated under NSPS.

Existing facilities are assumed to retire after 50years of service. Assuming an increase in demandfor electricity ranging from 2 to 3 percent per year,emissions will increase to 7 to 11 percent above cur-rent levels by 2000, decline to about 50 to 75 per-cent of current levels by 2025 to 2030, and then be-gin to climb again. However, as figure 11 B shows,these trends are extremely sensitive to the averagelife of existing sources, assumed to be 50 years forthe estimates presented above. Figure 11 B illustratesemissions trends assuming 2.5 percent growth peryear, but varying the average retirement age of ex-isting utility plants. A 40-year retirement age wouldcause emissions to decline steadily to about 50 per-cent of current levels by 2015 to 2020, and subse-quently rise. If the useful life of existing plants isextended to 60 years, emissions might rise to about20 percent above current levels by 2010, declineto about 80 percent of current amounts by 2030,and then begin to rise again.

Figure 11 C shows the effect of limiting allowableemission rates now, as opposed to waiting forNSPS-regulated new sources to replace existingutilities. The distance between the ‘‘base case’curve (no change in current laws and regulations)and the ‘ ‘emissions rate limitation curves repre-


Figure 11.— Forecasts of Utility Sulfur Dioxide Emissions for the Eastern 31-State Region of the United States

SOURCE: Office of Technology Assessment

Ch. 4—The Pollutants of Concern . 63—

sents the difference in emissions at any point intime. A 1.5 lb sulfur dioxide per million Btu ‘ ‘emis-sions cap’ on all Eastern utility sources by 1990would reduce emissions to about 50 percent of cur-rent levels. Emissions would then increase to about60 percent of current levels by 2025 and (after allexisting sources retired) follow the same growthtrend as the base case by 2030. Under a 1.2 lb permillion Btu cap by 1990, emissions would decreaseto 40 percent of current emissions by 1990, and thenrise to about 60 percent of current levels by 2025.Assuming a shorter retirement age would, ofcourse, decrease the length of time during which

the base case and the emissions cap scenarios sub-stantially differed, and a longer retirement agewould increase that time.

The range of projections from the simple modeldiscussed above agrees reasonably well with themore sophisticated projections presented earlier inthis section. Projections beyond 2000 to 2010 arepresented to illustrate how emissions levels mightrespond to plausible changes in electricity demandand utility operating procedures, but should not beconsidered accurate forecasts, as many other fac-tors may change over so long a time.

PATTERNS OF POLLUTANT EMISSIONS,AIR CONCENTRATIONS, AND DEPOSITION

Geographical Emissions PatternsFigures 12, 13, and 14 display maps of emissions

densities (in tons per square mile per year) for sulfurdioxide, nitrogen oxides, and reactive hydrocar-bons, respectively. For all three pollutants, emis-sions densities are generally greater in the East thanin the West.

Geographical Patterns of Depositionand Air Concentrations for

Transformed Pollutants

Figures 15 through 18 display maps of depositionlevels for acidity and sulfate in precipitation, andair concentrations for airborne sulfate and ozone—each of which is a major determinant of potentialdamage from transported air pollutants. Patternsof rainfall acidity and sulfate deposition, and air-borne sulfate concentrations, are similar over theEastern United States. The regional distributionof ozone differs substantially from the other three.

The best information available on patterns ofacidic deposition comes from monitoring networksthat collect rainfall samples. Though only about halfof all acid deposition over the Eastern United States

comes from precipitation, dry deposition of gaseousand particulate pollutants is not extensively moni-tored. Figure 15 shows average annual precipationacidity (measured as ph*) throughout North Amer-ica during 1980. Figure 16 shows the geographicalpatterns of of wet-deposited sulfate. The highestdeposition rates center around eastern Ohio, west-ern Pennsylvania, and northern West Virginia. Aband surrounding this area—from the AtlanticOcean west to the Mississippi River, and fromsouthern Ontario to northern Mississippi, Ala-bama, and Georgia—receives from 50 to 80 per-cent of these peak deposition rates. The data usedto construct this map are from 1980; deposition willvary from year to year at any given location, butthe broad pattern will probably remain quite sim-ilar.

Figure 17 displays airborne sulfate concentrationsin rural and remote areas, illustrating large-scale,regional patterns. The highest concentrations occurin a broad band covering the Midwest and Mid-dle Atlantic States.

*Acidity is measured in pH units. Decreasing pH corresponds toincreasing acidity. The pH scale is not linear; compared to a pH of6, pH 5 is 10 times more acid, pH 4 is 100 times more acid, andso on.


Figure 12.—Sulfur Dioxide Emissions Density (tons/mile 2, 1980)

SOURCE Environmental Protection Agency, based on data from National Emission Data System

Patterns of ozone concentration are also available osition, centering on North and South Carolina.from monitoring data, Figure 18 displays growing- A band of elevated ozone extends from the Mid-season average ozone concentrations, after elimi- Great Plains States to the east coast, as far northnating local-scale variations due to urban influ- as central Indiana and south to the central Gulfences. In the Eastern United States, peak values Coast States.for ozone are found further south than for acid dep-

THE REGIONAL PATTERNS OFSULFUR OXIDES TRANSPORT

How pollutant emissions from a particular region Figure 19 schematically illustrates the gradual(or group of regions) affect ambient air quality and transformation and deposition of sulfur pollutionpollutant deposition at some other location is a ma- as an air mass travels downwind over several days.jor controversy in the long-range transport debate. Sulfur pollution can be deposited in both its emittedEmitted pollutants are transformed, transported, form, sulfur dioxide (lighter shading), and as sulfateand deposited through a complex chain of chemical (darker shading), after being chemically trans-and physical processes. formed in the atmosphere. Both forms can be de-

Ch. 4—The Pollutants of Concern . 65

Figure 13.— Nitrogen Oxide Emissions Density (tons/mile 2)

SOURCE Environmental Protect Ion Agency, based on data from National Emission Data System

Figure 14.—Hydrocarbon Emissions Density (tons/mile 2)

SOURCE Environmental Protection Agency, based on data from National Emission Data System


Figure 15.— Precipitation Acidity—Annual Average pH for 1980, Weighted by Precipitation Amount

/“/“

/“ ● 6.80

//“

/“/“

/“● 5.44

Legend:

“ / v \

u(

Data compiled from Canadian 5.0and American monitoring 5.5networks.

SOURCE: Impact Assessment, Work Group 1, United States-Canada Memorandum of Intent on Transboundary Air Pollution, final report, January 1983


Figure 16.—Sulfate in Precipitation, 1980 (annual deposition in milliequivalents/meter 2)

●● 2.8

● 6.6

1

20

Legend:


Figure 17.—Airborne Sulfate—Annual Average Concentration for 1977-78 (micrograms/meter 3)

NOTE: Contours are baaed on data collected during selected months to represent seasonal averages between August 1977 and June 1978 at SURE II stations.

SOURCE: B. L. Neimann, “Data Bases for Regional Air Pollution Modeling,” presented at the EPA Regional Air Pollution Modeling Workshop, Port Deposit, Md., October 1979.


Figure 18.–Ozone Concentration–Daytime, Growing Season Average for 1978(parts per billion, June to September daily 7-hr average)

SOURCE: J. Reagan, personal communication, Environmental Protection Agency, 1983.

posited ‘ ‘wet’ (i.e., by removal from the air dur-ing periodic precipitation events) and ‘ ‘dry’ (bythe slow, continuous removal of gaseous and par-ticulate sulfur oxides).

As distance from the emission source increases,the relative amount of sulfur deposited in each ofthese forms changes. Dry deposition predominatesclose to the emission source; wet deposition pre-dominates in distant areas. Most scientists estimatethat these two processes deposit about equalamounts of sulfur when averaged annually over theEastern United States. Both wet and dry deposi-tion contribute to the total acidity received byecosystems.

Computer models of pollution transport attemptto describe this process mathematically. Transportmodels are currently the only practical procedure

available to estimate the relationship between areasof origin and areas of deposition. * Transport mod-els for sulfur oxides have been available for severalyears, though their accuracy is still a subject of sci-entific debate. Appendix C discusses the strengthsand weaknesses of these models. Preliminary mod-els of nitrogen oxides transport are just now beingdeveloped.

The model results are best used to estimate oneregion’s relative contribution to deposition inanother, rather than for projecting the magnitudeof deposition quantitatively. The discussion that fol-

“Newly developed tracer techniques may provide additional infor-mation on pollution transport. The U.S. and Canadian Governmentsare jointly conducting the ‘‘cross-Appalachian tracer experiment’(CAPTEX), using a chemical called to trace the flowof acidic pollutants from sources in Ohio and Ontario.


Figure 19.—The Effects of Time and Distance on Conversion and Deposition of Sulfur PollutionSulfur can be deposited in both its emitted form, sulfur dioxide (lighter shading), and as sulfate (darker shading), after beingchemically transformed in the atmosphere. Both compounds can be deposited in either dry or wet form. The relative amountof sulfur deposited in these forms varies with distance from emission sources. Dry deposition predominates in areas closeto emission sources. Wet deposition is responsible for a larger percentage of pollutant load in areas distant from source regions.

SOURCE Office of Technology Assessment

lows characterizes current patterns of sulfur oxidetransport, but should not be considered a quanti-tative description.

The results of transport models suggest that pol-lutants travel from one region to another, in alldirections, with greater movements of pollutantsfrom west to east and from south to north than inother directions. In addition, while pollutants cantravel long distances, emissions within a region con-tribute a large share to total deposition in thatregion.

To illustrate these points, Eastern North Americacan be divided into four regions as shown in figure20. These regions were chosen to intersect at thearea of peak wet sulfur deposition in 1980, to min-imize deposition biases for any one region. Figure

20 also displays the percentage of sulfur dioxideemitted in each region, and model-based estimatesof the percentage of total (wet plus dry) sulfurdeposited. Sulfur dioxide emissions are roughlycomparable in the northeastern region (I), south-eastern region (II), and southwestern region (III).Emissions in the northwestern region (IV) are overtwice the amount of any of the other regions. Totalsulfur deposition is lowest in the southern regions(II and 111) and highest in the northern regions (Iand IV).

Figure 21 presents model-based estimates of howmuch deposition in each region originates fromwithin its borders, and from each of the otherregions. For example, the pie chart in the upperright shows that, of the total sulfur deposited in


Figure 20.— 1979 Sulfur Dioxide Emissions and Estimated Sulfur Deposition—Percent Contributedand Received in Four Subregions Covering the Eastern Half of the United States

EmissionsPercentage of Eastern sulfur dioxide emissions

or sulfur deposition.

35-400/0

m25-350/o

*

10-15 ”/0

Deposition

I

SOURCE: J. Shannon, personal communication, Argonne National Laboratory and E. H. & Associates, Inc., 1982.

99-413 0 - 84 - 6 : QL . 3


Figure 21.— Percent of Sulfur Deposition Estimated To Originate From Within Each Regionand From Other Regions (winter and summer 1979)

—

From

--27$/0 /

I I III

\570/0


region I (northeastern), approximately 40 percentoriginates within its own borders, about 40 percentcomes from region IV (northwestern), and about’20 percent from the other two regions combined.

When regions as large as these are analyzed, eachcontributes as much or more to its own depositionas any other single region contributes to it. How-ever, because all regions contribute to depositionin all other regions, a large percentage of deposi-tion in any given region (in some cases over 50 per-cent) comes from outside. The greatest amountsof interregional transport follow the direction ofprevailing winds—generally west to east and southto north.

While the analysis above indicates the magnitudeand direction of interregional transport, it does notshow the average distances sulfur pollutants cantravel. Figure 22 displays model-based estimatesof the percentage of deposition due to long-distancetransport, arbitrarily defined as greater than 500km (300 miles). A 500-km radius circle is shownto illustrate the scale of transport being discussed.Because wet deposition predominates in remoteareas and dry deposition predominates close toemission sources, the two processes are illustratedseparately.

In general, long-distance transport accounts fora greater percentage of wet deposition than of drydeposition. Throughout the Midwest and CentralAtlantic States, about 30 to 50 percent of the wetdeposition originates from emissions greater than500 km away, as compared to 10 to 30 percent fordry deposition. Throughout New York and NewEngland, long-distance pollutant transport con-tributes 50 to 80 percent of the wet deposition and30 to 60 percent of the dry deposition. Over muchof the South, most of the deposition originates fromsources within 500 km—about 10 to 30 percent ofboth wet and dry deposition is due to long-distancetransport.

These results are model-based simulations of the1980 summer season. The percentages will vary forother seasons and years, but the broad patternsshould be similar.

The accuracy of pollution transport models,which use detailed emissions data and sophisticatedmeteorology, is a subject of scientific debate.

Measured levels of wet sulfur deposition for 1980agree fairly closely with OTA’s model-based cal-culations, averaging over large regions on an an-nual basis, Dry deposition is not monitored routine-ly enough to compare with model estimates. Themodel does not include nitrogen oxides, the othermajor contributor to acid deposition, nor does itportray the complex chemistry involving other at-mospheric pollutants.

The chemical reactions that produce acid deposi-tion involve a mix of pollutants present in gas form,dissolved in liquids (e. g., in clouds), and adheringto particles. Sulfur dioxide, nitrogen oxides, andhydrocarbons undergo transformations that mayfollow many complex chemical pathways. The se-quence actually followed depends on concentrationsof other chemicals that may inhibit, compete with,or enhance production and deposition of acidity.The same chemicals that transform or ‘ ‘oxidize’sulfur dioxide and nitrogen oxides to acid are alsoessential for forming ozone. In addition, the phys-ical characteristics of the atmosphere—windspeed,sunlight intensity, and rainfall frequency—affectthese transformations.

Predicting quantities of deposition at a specifictime and place is not yet possible, and may not befor many years. Making such predictions would re-quire detailed information on the current concen-trations of sulfur dioxide, nitrogen oxides, andhydrocarbons, as well as on the history of the airmass, including the frequency and amounts of freshpollutant inputs, the frequency and duration of re-cent rainfall events, and other specific chemical andphysical information.

However, current understanding of the variouschemical and physical processes involved permitsscientists to characterize very generally-over largespatial scales, and seasonal time scales-the effectsof reducing emitted quantities of various pollutants.The deposition changes that would result from re-ducing emissions of sulfur dioxide, nitrogen oxides,and hydrocarbons are discussed in appendix C, andare summarized briefly below:

Reducing sulfur dioxide emissions will reducethe total amount of acid formed in the atmos-phere, if levels of nitrogen oxides andhydrocarbons remain constant, and chemicalreactions are not limited by a shortage of ox-

74 . Acid Rain and Transported Air Pollutants: implications for Public Policy

Figure 22.— Estimated Percentage of SulfurOver 500 km (300 miles) Away

Wet deposition

Deposition From Emissions(summer 1980)

Dry deposition

Percent contributionfrom greater than 500 km away

>70%

50-700/0

30-50%0

10-30 ”/0

SOURCE: J. Shannon, personal communication, Argonne National Laboratory, 1982.

Ch. 4—The Pollutants of Concern 75

●

●

idizing agents. Furthermore, given these con-ditions, a decrease in sulfur dioxide emissionsshould decrease total sulfur deposition by anapproximately equal proportion. Where dep-osition will decrease can only be estimated ona regional scale.Decreasing nitrogen oxides emissions—whileholding hydrocarbon emissions constant—would decrease the amount of ozone producedover a large region, as well as the amount ofnitric acid ultimately deposited. The totalamount of sulfur deposited would probably notbe affected, although the conversion of sulfurdioxide to sulfate might accelerate somewhat,affecting the regional distribution of depo-sition.Reducing hydrocarbon emissions can decreasethe production of ozone, and of some keychemicals responsible for transforming sulfurdioxide and nitrogen oxides to acids. Thiswould slow the production of sulfuric and nitricacids, again altering the patterns of deposition,but probably would not affect total amountsof deposition.

If current regulations remain unchanged, sulfurdioxide emissions are projected to remain aboutconstant or increase slightly, hydrocarbon emissionsto remain about constant, and nitrogen oxides emis-sions to increase. Local acid deposition due to nitricacid would probably increase. The amount of totalsulfur deposited might remain about constant, butreactions involving increased nitrogen oxides emis-sions might cause the geographic patterns of sulfurdeposition to change.

Given the complexities of atmospheric chemistry,and inherent meteorological variability, as well asthe need to develop detailed emissions inventories(especially for nitrogen oxides and hydrocarbons),it is unlikely that a definitive model linking partic-ular sources to specific receptors will be developedin the next decade. Policy decisions to control ornot to control precursor emissions will have to bemade without the benefit of such precise informa-tion.

Chapter 5

The Regional Distribution of Risks

Contents

Page

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

No Congressional Action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80Aquatic Ecosystems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80Terrestrial Ecosystems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

Other Risks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91Visibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91Risk of Health Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

If Further Emissions Reductions Are Mandated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92Rates of Pollutant Emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94Utility Control Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95Risk to the Utility Industry. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

Risks of Shifts in Coal Production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

FIGURES

Figure No , Page

23. Estimated Percentages of Lakes Vulnerable to Acid Deposition in Sensitive Regionsof the Eastern United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

24. Estimated Percentages of Streams Vulnerable to Acid Deposition in Sensitivc Regionsof the Eastern United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

25. Freshwater Recreational Fishing— Relative Economic Importance . . . . . . . . . . . . . . . . . . . 8326. Production of Corn and Soybeans in 1978 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8427. Percent of Land Area Capable of Commercial Timbcr Production . . . . . . . . . . . . . . . . . . 8528. Estimated Gains in 1978 Corn and Soybean Yields From Reducing Ozone

Concentrations to “Natural” Levels, . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8629. Soil Sensitivity to Acid Deposition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8730. Agriculture— Relative Economic Importance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8831. Forestry— Relative Economic Importance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8932. Median Yearly Visual Range for Suburban and Nonurban Areas . . . . . . . . . . . . . . . . . . . 9033. Population Exposure to Airborne Sulfate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9134. Average 1980 Emission Rates for Sulfur Dioxide From Utility and Industrial Sources . 9335. Average 1980 Emission Rates for Nitrogen Oxides From Utility and

Industrial Sources. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9336. Cost of Reducing Sulfur Dioxide Emissions 10 Million Tons per Year, Nationwide

Increases in Annual-Average Electricity Bills for a Typical Residential Consumer . . . . . 9637. Cost of Reducing Sulfur Dioxide Emissions 6 Million Tons per Year,

Eastern 31 States Increases in Annual-Average Electricity Bills for aTypical Residential Consumer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

38. Expenditures for Residential Electricity —Relative Economic Importance . . . . . . . . . . . . . 9839. Electric Utilities-Selected Financial Indicators of Sensitivity to Control Expenditures . 9940. Quantities and Sulfur Content of Coals Produced for Electric Utilities,

by State—1980 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10041. Coal—Relative Economic Importance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

Chapter 5

The Regional Distribution of Risks

INTRODUCTION

Chapter 3 presented the risks of controlling andnot controlling transported air pollutants for theEastern 3 l-State region overall. However, the waysin which these risks are distributed throughout theregion arc of prime significance to the policy debate.Most importantly, considerable variation is foundin:

s

●

●

the distribution of pollution sources, andhence, the distribution of potential controlcosts ;the distribution and extent of resources at risk,their levels of exposure, and their inherent sen-sitivity to transported pollutants; andthe relative importance of the economic sec-tor at risk to each State’s economy.

Scientific uncertainties complicate the task ofdescribing the distribution of risk. However, evenif scientists attained ‘ ‘perfect knowledge’ of thecauses and consequences of transported air pollut-ants, different groups and regions of the countrywould bear these risks. Thus, while it is impossi-ble to precisely specify these groups and regions atpresent, the distributional aspects of transportedpollutants are inherently part of the policy problem.

This chapter describes how the risks associatedwith three pollutants —acid deposition, ozone, andairborne sulfate— are distributed. The order of dis-cussion closely follows the presentation in chapter3 of the aggregate risks to the Eastern 31 -State re-gion. This chapter, however, focuses on the region-al distribution of these risks, and is extensivelyillustrated with maps.

Two situations are described: 1) the risk of re-source damage and adverse health effects if Con-

gress maintains the status quo for pollutant emis-sions, and 2) the costs and economic effects ofadditional pollution-control measures that might beadopted.

Some of the risks of controlling or not control-ling transported air pollutants can be thought ofas ‘ ‘localized’ risks. For example, fewer than halfthe States contain deposits of high sulfur-contentcoal; only in these States could current coal pro-duction be lost due to additional pollution-controlrequirements. Similarly, only parts of the EasternUnited States contain lakes and streams consideredpotentially sensitive to acid deposition. Other riskscan be characterized as ‘ ‘distributed’ ‘—risks thatare present in Virtually all States in the Eastern re-gion, For example, crops are grown in all States.Three factors determine the relative importance ofozone-caused crop damage: 1 ) the concentrationof ozone in a State, 2) the sensitivities of a Statescrops to ozone, and 3) the importance of agricul-ture to the State economy. Likewise, the effects ofutility pollution-control costs depend both on theamount of the State income spent on electricity andon a State pollutant emissions.

In addition to describing the geographic patternsof risk from transported air pollutants, this chapterassesses the relative importance of five economicsectors of concern: agriculture, forestry and forestproduct-related industries, freshwater recreationalfishing, coal mining, and electricity generation. Thefirst four sectors vary considerably in economic im-portance from State to State—from a small percent-age of the regional average to several times thataverage. The last sector, electricity generation, ismuch more uniformly distributed.

79


NO CONGRESSIONAL ACTION

Aquatic Ecosystems

As discussed in chapter 3, lakes and streams areaffected not only by the acid deposition fallingdirectly on them, but also by the amount of acid-producing substances entering them from sur-rounding watersheds. Regions with soils and bed-rock that neutralize acidic deposition are not like-ly to be affected. The areas outlined in figures 23and 24 are thought to allow acidity to travel through

watersheds to lake and streams. These areas con-tain soils that either cannot neutralize acidity, orare so steep and rocky that rainfall has little con-tact with soils and runs directly into lakes orstreams. The size of the circles on each map illus-trates the extent of lake and stream resources ineach region. The greatest number of lakes is foundin the upper Midwest, followed by New England.The greatest mileage of small streams is found inNew England, followed by the mountain region of

Figure 23.-Estimated Percentages of Lakes Vulnerable to Acid Depositionin Sensitive Regions of the Eastern United States

n

SOURCE: The Institute of Ecology, “Regional Assessment of Aquatic Resources at Risk From Acid Deposition,” OTA contractor report, 1982

Ch. 5—The Regional Distribution of Risks . 81

Figure 24.—Estimated Percentages of Streams Vulnerable to Acid Depositionin Sensitive Regions of the Eastern United States

Do

SOURCE: The Institute of Ecology, “Regional Assessment of Aquatic Resources at Risk From Acid Deposition, ” OTA contractor report, 1982.

West Virginia, Kentucky, western Virginia, North numbers of moderately vulnerable lakes are foundCarolina, and eastern Tennessee.

However, because of local variation in soil andwatershed characteristics, not all the lakes andstreams within these regions will be vulnerable toacidic deposition. The intensity of shading withineach outlined area indicates the percentage of lakesand streams estimated to be vulnerable to acid dep-osition, based on water quality characteristics. Thenortheastern regions have the greatest percentagesof ‘extremely’ vulnerable lakes and streams—weestimate about 30 to 40 percent of the over 5,000lakes and 10 to 20 percent of the 65,000 streammiles in the area. These regions also receive highlevels of acidic deposition. In addition, large

in the upper Midwest, and extensive mileages ofmoderately vulnerable streams are found in the cen-tral Appalachian/Blue Ridge regions.

Directly comparing current conditions to histor-ical data, only a small number of surface watersin North America are known to have acidified. Datafrom several decades ago are sparse; in addition,differences in sampling and measurement tech-niques make comparisons with current data dif-ficult. A review of the available evidence foracidification found significant changes in waterbody chemistry in studies of: 250 lakes in Maine,94 lakes in New England, 40 lakes in the Adiron-dacks, and two streams in the New Jersey Pine Bar-


rens, as well as in 16 lakes near Halifax, NovaScotia, 22 lakes in the LaCloche Mountains, On-tario, and Clear Lake, Ontario. Changes in waterchemistry over time have also been reported for 38North Carolina streams, 6 Nova Scotia rivers, and314 surface waters in Pennsylvania; however, firmconclusions cannot be drawn from these studies. 1

In the Adirondack Mountains, the only U.S. lo-cation in which scientists have documented fishpopulation declines, the New York State Depart-ment of Environmental Conservation has reportedthe disappearance of fish populations in about 180lakes. Researchers have found correlations betweenacidity levels and survival of fish in Adirondacklakes and streams. Four other areas are known tohave experienced losses of fish populationsassociated with surface water acidification: 1 ) theLaCloche Mountain region of Ontario, 2) NovaScotia, 3) Southern Norway, and 4) SouthernSweden.

Acid deposition may not be the sole cause of thechanges discussed above. Other man-inducedstresses and natural processes can also alter surfacewater chemistry. However, the largest numbers ofacidified and extremely sensitive lakes and streamsare located in regions currently receiving the highestlevels of acid deposition.

Though the economic value of these particularsensitive resources cannot yet be estimated, the Fishand Wildlife Service has estimated that about 21million people spent $6.3 billion on all recreationalfreshwater fishing activities in the Eastern UnitedStates during 1980. Figure 25 illustrates how theseexpenditures vary by State, displaying the impor-tance of recreational fishing to each State’s economyrelative to the 3 1-State regional average.

‘R. A. 1,inthurst, J P. Ilakt, r, and A. M 13art uska, 4‘ F; f’fccts of

.Acidic Deposition A Ilricf’ Review, ” Proct’eding-s of the .4PCA Special-(}’ (~onfi’rencc on Atnmspheri( Dt’posltiorr, Air Pollution Control Asso-( iat ion, Ncr\cmber 1982, rei.lew ing I ntcrnat ional Electric ResearchF,xchange, Efk-ts of S02 ,and 1[s Deri\ati\e.s (m Hea/th and EC (]]o,~,(kmtral Electricity Generatin~ Board, Leathcrhead, England; NationalResearch Counci] of’ Canada, Acidification in the Canadian Aquaticf~n~ironment: .%lentilic Criteri,i ftir .4ssessing the IW&ts of .4cidlcI)cposirion on AquarJc Ecos)sfcms, Associated Committee on Scien-tific Criteria for En\’ironmentat Quality, National Research Council[Jf’Canada, NRC(; ISO. 18475, 1981 ; and J Baker, ‘ ‘Effects on AquaticBiology, Drafi Critical Asst’ssn]ent Lhcunlcnt: 7Yle rlcidlc Lkposi-

tion Phenomenon and 1[s Ef]it(.s, Ch,ipter E-5, 5.6 Fisht.s (Octobcr

1982)

Because there are few data to determine wheth-er lakes and streams sensitive to acid deposition arethose preferred for recreational fishing, OTA can-not estimate potential regional economic lossesresulting from the elimination of fish populations.One local-scale study, however, has estimated lossesto New York resident anglers of approximately $1.7(1982 dollars) million annually from lost fishing op-portunities in about 200 acidified Adirondack lakesand ponds. 2 Potential losses to individuals whoselivelihoods depend on the recreational fishing in-dustry were not estimated. On a regional scale, theStates at greatest economic risk are those with: 1)the greatest numbers of sensitive lakes, 2) thehighest levels of acid deposition, and 3) the highestrelative expenditures for recreational fishing.Among these are the New England States of Maine,Vermont, and New Hampshire; the Appalachianregion of West Virginia and eastern Kentucky; andparts of the Midwestern States of Wisconsin andMinnesota.

Terrestrial Ecosystems

Figure 26 shows major agricultural productionareas for two major crops, corn and soybeans.Figure 27 presents the location of forests.

Figure 28 illustrates the crop yield gains thatmight occur if ozone concentrations were loweredto estimated natural background levels. The regionsof highest crop production—an area slightly northof the peak ozone concentrations—show the greatestimprovement. Here, in the corn and soybean beltof the Midwest, even moderate levels of ozone cancause substantial crop damage. For Iowa, Indiana,and Illinois, reducing ozone concentrations tobackground levels might cause both soybean andcorn yields to increase by about 20 to 40 millionbushels per year in each State. (See app. B forpotential productivity gains in wheat and peanutswith decreased ozone concentrations. )

Comparing figures 15 (patterns of acidity) and 26(current corn and soybean yields) indicates thatelevated levels of acid deposition occur withinseveral major crop-producing States, includingIllinois, Indiana, and Ohio. Reductions in both soy-— . .—

‘F. (;, hlenz and J. K. hlullen, ‘ ‘Ac edification Impact on Fish-eries: Substitution and the t’aluatlon of Re( reat ional Resources, Eco-n(mji[ Pcrspt’cti\w on Acid Deposition, ‘1’.11. Cro(ker (cd ) (Ann Ar-tmr: Butter-worth Press, 1984).

Ch. 5—The Regional Distribution of Risks ● 8 3- .

Figure 25.—Freshwater Recreational Fishing— Relative Economic Importance

1980 recreational fishing expenditures by State (expenditures on freshwater recreational fishing, scaledby State income, compared to regional average)

SOURCE: Office of Technology Assessment, from U.S. Census Bureau and U.S. Fish and Wildlife Service data

bean and corn productivity have been observed infield experiments with simulated acid rain, butother experiments have yielded contradictoryresults.

Scientists have recently discovered productivitydeclines in several tree species throughout the East-ern Unitcd States from New England to Georgia.Acid deposition, ozone, heat)-metal deposition,

drought, severe winters or a combination of theseare possible causes under investigation.

By coring trees and measuring the thickness of’annual growth rings, scientists have observed markedreductions in productivity beginning about 1960in red spruce, shortleaf pine and pitch pine, Cor-ings from about 30 other species at 70 sites through-out the East are currently being analyzed to deter-

Ch. 5—The Regional Distribution of Risks 85

Figure 27.— Percent of Land Area Capable of Commercial Timber Production

aThe U S Forest Service defines commercial timberland as lands capable of producing greater than 20 cubic feet of industrial roundwood per acre per year, in natural stands

SOURCE Oak Ridge National Laboratory, 1981, U S Forest Service State forest Inventory

mine the geographic extent and severity of the prob-lem. Routine measurements of tree growth by theU.S. Forest Service have shown productivity de-clines in loblolly pine and shortleaf pine during the1970s in the Piedmont region of South Carolinaand Georgia.

Although ozone is known to harm trees, quan-titative estimates of forest productivity losses dueto ozone are lacking because of the difficulty of per-forming experiments on long-lived species. By com-paring figures 18 and 27, one can observe that ele-vated ozone concentrations coincide with forestedregions in the southern Appalachian Mountains,the Ozark Mountains, and parts of the southernsoftwood area of the Southeastern and South Cen-tral States.

Much of the forested area of New England, theAppalachian Mountains, and parts of the southernsoft wood forests of Alabama and Georgia receive

elevated levels of acid deposition, as can be seenin figures 15 and 27. However, the relationships be-tween forest health and levels of deposition are notwell known. The nitrogen deposited is a beneficialnutrient, but the acidity might damage leaf sur-faces, remove nutrients from foliage, alter suscep-tibility to pests (either beneficially or detrimental-ly), or alter forest soil chemistry.

Forest soils are at risk from acid deposition dueto: 1 ) release (mobilization) of soil-bound metals,such as aluminum, that are toxic to plants if pres-ent in sufficient quantity, 2) potential leaching ofcalcium, magnesium, and other nutrients essentialfor plant growth from the soil, and 3) further acid-ification of soils. Figure 29 displays the geographicdistribution of these risks. Available informationallowed OTA to identify’ those counties in whichsoils susceptible to these effects predominate; oth-er locations where they occur to a lesser extent couldnot be determined.


Figure 28.—Estimated Gains in 1978 Corn and Soybean Yields From ReducingOzone Concentrations to “Natural" Levels

Corn yield gains (bushels/acre) with ozone reductions

based on 1978 agriculture census and 1978 EPA ozone data.

SOURCE Oak Ridge National Laboratory, “An Analysis of Potential Agriculture and Forest Impacts of Long-Range Transport Air Pollutants, ” OTA contractor report1983

Ch. 5—The Regional Distribution of Risks ● 8 7

Figure 29.-Soil Sensitivity to Acid Deposition (nonagricultural)

Forested and range areas with soils thought to be susceptible to the effects of acid deposition. Shaded areas represent countiesin which a susceptible soil type predominates. The three levels of shading correspond to different soil types, and potentialeffects, rather than to degrees of susceptibility.

Legend

SOURCE: Oak Ridge National Laboratory, “An Analysis of Potential Agriculture and Forest Impacts of Long-Range Transport Air Pollutants,” OTA contractor report, 1983.

99-413 0 - 84 - 7 : QL . 3


Figure 30.-Agriculture— Relative Economic Importance

elative importance of agriculture-related income to State income, 1978-80

SOURCE: Office of Technology Assessment, from U.S. Census Bureau data.

Soils must already be acidic—about pH 5 orlower—to release aluminum in the presence of thestrong acids in acid deposition. Regions where nat-urally acid soils predominate are shown as themedium and light gray areas in figure 29. However,the soils in the light gray areas trap sulfate in theirlower layers, which somewhat reduces the amountof this strong acid available for releasing aluminum.

Soils that are both acidic and do not impede theflow of sulfate (shaded a medium gray in fig. 29)

predominate in New England and northern NewYork State, and parts of the upper Midwest andFlorida. These regions are considered most suscep-tible to the toxic effects of aluminum; however,whether resulting aluminum concentrations will behigh enough to significantly alter forest productivityis not yet known.

Figure 29 also displays regions of the EasternUnited States where nutrient loss is of concern. Thedark patches are areas with moderately acid soils.


Figure 31.— Forestry -Relative Economic importance

Relative importance of forestry-related income to State income, 1978-80

Key:


Loss of calcium, magnesium, and other nutrientsfrom these relatively uncommon soils throughdecades of exposure to acid deposition might causethese soils to further acidify. Nutrients can also belost from more acidic soils—typically already nu-trient poor—but probably at a slower rate. Mostsusceptible are those regions (shaded medium gray)with nutrient-poor acid soils that allow sulfate tomove freely, potentially carrying away nutrientsfrom the soil, plant canopy, and decaying plant

material. However, whether the rate of nutrient lossfrom these soils is more rapid than replacement byweathering is unknown.

Both agriculture and forestry are important tothe overall economy of the Eastern United States,each providing about 3.7 percent of the total re-gional income. Agriculture and related services areresponsible for about $22 billion of the region’s in-come; forestry, wood, lumber, paper, and allied

90l Acid Rain and Transported Air Pollutants: Implications for Public Policy— — —

Figure 32.—Median Yearly Visual Range (miles) for Suburban and Nonurban Areas

Data from 1974-76, estimated from visual observations and other methods

SOURCE. Trijonis, J., and Shapland, R., 1979: Existing Visibility Levels in the U. S.: Isopleth Maps of Visibility in Suburban/Nonurban Areas During 1974-76, EPA450/5-79-010, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina.

industries generate about $21 billion in personalincome.

Figures 30 and 31 display those States’ economiesthat depend most on these sectors. When consider-ing potential crop damage, States subject to thegreatest monetary risk are those that are both:1) exposed to elevated ozone (fig. 18), acid deposi-tion (fig. 15), or both; and 2) generate the largestshare of State income from agriculture (fig. 30).Iowa, Illinois, Indiana, Missouri, Arkansas, Mis-sissippi, Alabama, and North Carolina are atgreatest economic risk from ozone damage. If aciddeposition affects crops, the above States plus Ver-

When considering potential forestry-relatedeffects, States at greatest economic risk are thosethat: 1) generate the largest share of income fromforestry (fig. 31); 2) are exposed to elevated ozone(fig. 18), acid deposition (fig. 15), or both; and 3)contain soils susceptible to change (fig. 29). Statesat greatest economic risk from ozone include thesouthern softwood region extending from Arkan-sas to North Carolina. Many of these States receivehigh levels of acid deposition and have soils con-sidered susceptible to mobilization of toxic alumi-num or nutrient loss, as do the New England Statesof Vermont, New Hampshire, and Maine.

mont would be at greatest risk.


Figure 33.—population Exposure to Airborne Sulfate (an indicator of potential health effects from sulfatesand other airborne particulate in each State)

concentration in micrograms per cubicmeter). Model estimates based on1978 data.

SOURCE Brookhaven National Laboratory, Biomedical and Environmental Assessment Division, “Long Range Transport Air Pollution Health Effects, ” OTA contractorreport, May 1982

OTHER RISKS

Materials

Materials at greatest risk from exposure to acidicdeposition include metals, such as steel and zinc,and stone masonry. Regions at greatest risk cor-respond to those with the greatest population den-sities and areas with historically significant buildingsand monuments, Scientists estimate that the bulkof materials damage is caused by local-scale pol-lutants, and that sulfur dioxide emissions are re-sponsible for a major share of pollutant-induced

damages to a broad range of materials, Elevatedozone concentrations are harmful to such materialsas paint on home exteriors and rubber. The dis-tribution of materials sensitive to air pollutants isnot well known, since inventories have been takenin very few areas.

●

Visibility

For the Eastern United States, sulfate is the singlemost important contributor to visibility degrada-


tion; patterns of impairment in the region correlatefairly well to airborne sulfate concentrations (pre-sented earlier as fig. 17). Sulfate is currentlyestimated to account for 50 percent of visibilitydegradation annually, and 70 percent of summervisibility degradation in the East. In the West,nitrates may play a larger role than sulfates invisibility impairment. Figure 32 shows annual aver-age risibilities throughout the Nation for the mid-1970’s, the most recent information available toOTA. Visibility in the Eastern United States hasimproved slightly over the past decade, but is stillless than pre-1960 levels.

Current Eastern visibility levels are generally farlower than those in the West. However, it shouldbe noted that unimpaired Eastern visibility levelswould be significantly lower than in the West, dueto higher Eastern humidity levels. In addition,where visibility is already low, an increment of ad-ditional sulfate may not reduce visibility much fur-ther; in more pristine areas, the same incrementof additional sulfate may significantly decreasevisibility.

Risk of Health Effects

The health risk to any individual is thought tobe correlated to sulfate concentrations in the atmos-phere. However, whether premature mortality ob-served in statistical studies actually results fromsulfate in air pollution, from different componentsof the sulfate-particulate mix, or from other fac-tors not considered, is unknown. This risk variesfrom increases of less than 1 percent in excess mor-tality in the West to about 4 percent (a range fromabout O to 10 percent) in the regions of highest sul-fate concentration. The health risk to a State is de-termined both by the potential increase in mortalityand by the State’s population. Some of the North-eastern States with the highest population densities(e.g., New York, Pennsylvania, and Ohio) are alsoexposed to the highest airborne sulfate concentra-tions, and are therefore at greatest risk. Figure 33displays the total exposure of each State’s popula-tion to airborne sulfate, an indicator of the relativerisk of premature mortality in each State.

IF FURTHER EMISSIONS REDUCTIONSARE MANDATED

Rates of Pollutant Emissions

The regional patterns of pollutant emissions areperhaps the best indicator of how costs to controltransported air pollution might be distributed. Fig-ures 12 and 13 in chapter 4 display maps of emis-sions densities (in tons per square mile) for sulfurdioxide and nitrogen oxides. This section discussesanother measure of pollutant emissions more direct-ly related to potential control costs—emission rates,expressed as pounds of pollutants per quantity offuel burned.

To date, the major legislative proposals to con-trol acid deposition have focused primarily on sulfurdioxide emissions. Though emissions reductionscan be allocated to States in many ways, most ofthese bills propose reductions based on emissionrates. This approach avoids penalizing areas emit-ting large quantities of sulfur dioxide because of

high electrical or industrial productivity; instead,reductions are concentrated in areas that emitgreater-than-average amounts of sulfur dioxide fora given amount of production.

Sulfur dioxide emission rates vary widely amongStates. Emission rates can be decreased either byusing: 1) a lower sulfur fuel, or 2) technologicalmeans, such as capturing the sulfur dioxide gas with‘‘scrubbers’ after the fuel is burned.

Figure 34 displays estimates of statewide averagesulfur dioxide emission rates from utilities and in-dustrial boilers. Within the Eastern 31-State region,utilities account for about 70 to 75 percent of sulfurdioxide emissions, and industrial boilers for about10 to 15 percent.

The Midwestern States have the highest utilityemission rates, and are therefore at greatest riskfrom additional pollution control regulations. In-

Ch. 5—The Regional Distribution of Risks 93

Figure 34.—Average 1980 Emission Rates for Sulfur Dioxide From Utility and Industrial Sources (lb SO2/MMBtu)

SOURCE: E. H. Pechan & Associates, from Energy Information Administration data (EIA forms 4 and 423), and EPA National Emissions Data System (NEDS).


Figure 35.—Average 1980 Emission Rates for Nitrogen Oxides From Utility and Industrial Sources (lb NO 2/MMBtu)

I

SOURCE: E. H. Pechan & Associates, from Energy Information Administration data (EIA forms 4 and 423), and EPA National Emissions Data System (NEDS)


dustrial boiler emission rates are more evenly dis-tributed, with highest average rates occurring inthe Midwestern and Central Atlantic States.

Nitrogen oxides are both a component of aciddeposition and a precursor to ozone. Reducingnitrogen oxides emissions from existing sources hasnot been proposed to date, although some bills haveprohibited further increases in nitrogen oxides emis-sions or allowed reductions to substitute for sulfurdioxide reductions.

The three major sources of nitrogen oxides inthe 31 -State region are mobile sources (45 percent),utilities (35 percent), and industrial boilers (15 to20 percent). Highway vehicles account for about75 percent of the emissions from mobile sources,or about one-third of total Eastern U.S. nitrogenoxides emissions.

Figure 35 displays State-average nitrogen oxidesemission rates from utilities and industrial boilers,respectively. As with sulfur dioxide emissions, pro-posals for controlling nitrogen oxides might allocatereductions on the basis of emission rates. Emissionrates are more evenly distributed for nitrogen ox-ides than for sulfur dioxide. Additional mobile-source controls would regionally distribute costs ac-cording to patterns of new vehicle purchases.

Utility Control Costs

Figure 36 displays the effects of further pollutioncontrol on the cost of electricity. Annual increasesin a typical residential consumer’s electricity billsare estimated for a 10-million-ton reduction in sul-fur dioxide emissions from existing utility sources.Total costs of such a program would be about $3to $4 billion per year (1982 dollars), assuming eachutility chooses the most cost-effective method of re-ducing emissions. Emissions reductions are allo-cated to States on the basis of 1980 utility emis-sion rates. (Similar to several legislative proposals,reductions are based on each State’s share of sulfurdioxide emitted in excess of 1.2 lb per million Btuof fuel burned. ) For this hypothetical pollution-control plan, the reduction formula applies to thecontiguous 48 States; however, reductions, in theEastern 31 States would be quite similar if the for-mula applied only to these Eastern States. * The

“W’estern sulfur dioxide cm]ssions in excess of 1.2 lb per millionBtu are less than 5 percent of the allocated reductions.

highest rate increases occur in the MidwesternStates and a few Southeastern and New EnglandStates.

Figure 37 displays the cost of a smaller pollutioncontrol program. About 6 million tons of sulfur di-oxide could be eliminated annually in the Eastern31 States by limiting utility emission rates to 2 lbper million Btu, at a cost of about $1 to $1.5 bil-lion per year. If the control program was confinedto the 22-State region receiving the highest levelsof acid deposition, about 4.8 million tons per yearcould be eliminated for annual costs of $1 billionor less.

These cost estimates assume that all requiredemissions reductions would come from utilities, andthat additional emissions coming from new utilityplants or increased use of existing plants are notoffset by further reducing existing plant emissions.In addition, these cost estimates assume that theuse of control technology (e. g., scrubbers) is notrequired.

Similar to the maps presented earlier depictingthe relative economic importance of recreationalfishing, agriculture, and forestry, figure 38 displaysthe relative share of State income spent on residen-tial electricity. For the region as a whole, about 2.3percent of personal income, or $26 billion, is spenton electricity. The distribution of these expendituresby State is much more uniform than for the sec-tors discussed above, but is somewhat higherthroughout the South.

Risk to the Utility Industry

Additional expenditures to control emissionscould potentially affect the financial health of in-dividual utilities. Three major factors determine theextent to which utility companies could be affected:1) the extent of emissions reductions required undera given control program, 2) the utility’s financialposition, and 3) State-level regulatory policies thataffect a utility’s short- and medium-term ability topass on the costs of pollution control to consumers.OTA did not attempt to analyze how these factorswould affect the financial health of the more than100 major publicly owned utilities in the 31 EasternStates, but drew on available information to assessthe relative sensitivity of each State utility sectorto further emissions control.

96. Acid Rain and Transported Air Pollutants: Implications for Public Policy

Figure 36.-Cost of Reducing Sulfur Dioxide Emissions 10 Million Tons per Year, Nationwide Increases in Annual”Average Electricity Bills for a Typical Residential Consumer

Figure 39 displays patterns of utility earnings andbond ratings for 1980 in each State, two indicatorsof the financial health of a State’s utility sector. Fig-ure 34 shows statewide average 1980 utility emis-sion rates for sulfur dioxide—the best indicator ofthe extent of utility-sector reductions likely to berequired under most of the control proposals in-troduced in the 97th and 98th Congresses.

Comparing figures 34 and 39 shows that fewStates both: 1) had high emission rates, and 2) fell

into the least favorable financial category, in 1980.However, several Midwestern States with highemission rates (and, therefore, potentially subjectto extensive control requirements) fell into the mod-erately favorable financial categories.

Policies established by State public utility com-missions can affect an individual utility’s near-termability to pass on the costs of pollution control toconsumers. For example, for coal-burning utilitiesthat might choose to use scrubbers, the State’s pol-


Figure 37.—Cost of Reducing Sulfur Dioxide Emissions 6 Million Tons per Year, Eastern 31 States Increasesin Annual-Average Electricity Bills for a Typical Residential Consumer

Key:

SOURCE Office of Technology Assessment, based on analyses by E. H. Pechan & Associates, Inc.

icies regarding capital investment, in combinationwith the utilities’ current financial ratings, deter-mine the burden of raising capital for constructingscrubbers. Results of a survey of current State reg-ulatory policies, and a discussion of their relativeimportance, are presented in appendix A. How-ever, these policies might change considerably ifa major Federal program to further limit pollutionemissions is enacted.

Risks of Shifts in Coal ProductionBecause switching to lower sulfur fuel is often

a cost-effective way to reduce sulfur dioxide emis-sions, emission-reduction schemes could cause coalproduction to shift from high-sulfur coal regionsto low-sulfur coal regions.

Figure 40 displays coal production by State forboth high- and low-sulfur coal. The size of each


Figure 38.—Expenditures for Residential Electricity—Relative Economic Importance

Relative share of State income spent for residential electricity, 1980

ffice of Technology Assessment, from U.S. Census Bureau and Edison Electric Institute data.

circle indicates the magnitude of State coal produc-tion. The shading indicates the average sulfur con-tent of the coals mined, using the darkest shadingsfor the highest sulfur coal. Midwestern and north-ern Appalachian high-sulfur coal States incur thegreatest risk of production losses, However, totalcoal production is projected to be unaffected; pro-duction gains of similar magnitudes would occurin the low-sulfur coal regions of Central Appalachiaand the West.

Of all the economic sectors at risk, coal miningis the least evenly distributed across the Eastern re-

gion. The approximately $7 billion of regional in-come from coal mining in the Eastern 31 States isconcentrated in 9 States, as shown in figure 41.States at greatest economic risk are those in which:1) a large share of State income comes from coalmining (fig. 41), and 2) most of the coal producedis of relatively high-sulfur content (fig. 40). Statesmeeting these criteria include West Virginia, Ken-tucky, Pennsylvania, Alabama, and Virginia. Forthese States, the income from coal mining is morethan twice the regional average, and more than 80percent of the coal produced emits greater than 1.2lb sulfur dioxide per million Btu when burned.


Figure 39.— Electric Utilities-Selected Financial Indicators of Sensitivity to Control Expenditures

Key for financial indicators

Sensitive to additional air pollution control requirements: relatively poor bond ratings and below-averagereturn on common equity in 1980.

Moderately sensitive to additional air pollution control requirements: poor bond ratings or below-averagereturn on common equity in 1980.

I I Insensitive to additional air pollution control requirements: relatively good bond ratings and above-averagereturn on common equity in 1980.

SOURCE K. Cole, et. al., “Financial and Regulatory Factors Affecting the State and Regional Economic Impact of Sulfur Oxide Emissions Control, ” OTA contractorreport, 1982


Figure 40.–Quantities and Sulfur Content of Coals Produced for Electric Utilities, by State–1980

Ch. 5—The Regional Distribution of Risks 101— —

Figure 41 .—Coal—Relative Economic ImportanceRelative importance of coal-related income to State income, 1978-80


Chapter 6

Policy Options

Contents

Page

Current Law and Recent Legislative Proposals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

Approaches and Options . . . . . . ..***.* .*.*.... . . . . . . . . ....**.* ● ..*.*** . . . . . . . 106Approach A: Mandating Emissions Reductions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106Approach B: Liming Lakes and Streams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111Approach C: Modifying the Federal Acid Deposition Research Program . . . . . . . . . . . . . . . . 115Approach D: Modifying Existing International and Interstate Sections of the Clean Air Act 118

TABLE

Table No. Page

5. Organization of the National Acid Precipitation Assessment Program . . . . . . . . . . . . . . . . . 115

Chapter 6

Policy Options

This chapter presents options for congressionalaction on acid deposition and other transported airpollutants. As background, it first describes existing

CURRENT LAWLEGISLATIVE

The present Clean Air Act is designed to con-trol airborne concentrations of pollutants that en-danger public health and welfare. The act requiresEPA to set National Ambient Air Quality Stand-ards (NAAQS), and makes each State responsiblefor bringing its air pollutant concentrations downto or below the NAAQS. * Despite these limitationson allowable concentrations, large quantities ofpollutants are still emitted and eventually depos-ited. Provisions were added to the act in 1977 toprohibit a State’s emissions from contributing toviolations of NAAQS in other States, or to any pol-lution problem in other countries. These provisions,however, appear to be ineffective for dealing withproblems of the geographic scope of acid deposition.

The act further restricts future emissions by plac-ing stringent emission limits on new sources of pol-lution, such as electric utilities and motor vehicles.These New Source Performance Standards (NSPS)are expected to achieve reductions in total emis-sions within 30 to 50 years. Continuing emissionsfrom both old and new sources, however, will main-tain or increase pollution levels during the next fewdecades unless additional controls are mandated.

To date, congressional action on acid depositionhas been limited to funding research. The Acid Pre-cipitation Act of 1980—Title VII of the EnergySecurity Act, Public Law 96-294—created an Inter-agency Task Force to conduct a comprehensive 10-year assessment of the causes and consequences of,and means and costs of controlling, transportedacidic pollutants, The Task Force presented an——

“National Ambient Air Quality Standards currently exist for sixpollutants: sulfur dioxide, nitrogen dioxide, ozone, total suspendedparticulate, carbon monoxide, and lead.

Federal statutes relating to transported air pol-lutants, and summarizes the legislative proposalsintroduced during the 97th and 98th Congresses.

AND RECENTPROPOSALS

Assessment Plan to Congress in June 1982. Underthe plan, Congress would receive policy-related “in-tegrated assessments’ between 1987 and 1989.

Several bills were introduced during the 97th and98th Congresses to accelerate the research programfrom 10 to 5 years; another bill would direct theTask Force to report to Congress on the progressof research, and provide recommendations for ac-tion, once every 2 years. Options for making theresearch plan more responsive to congressional (andpotentially, regulatory) needs are presented laterin this chapter under “Approach C: Modifying theFederal Acid Deposition Research Program.

Legislators have also introduced a variety of pro-posals to control acid deposition directly. Manywould establish a 31-State control region, and man-date reductions of annual sulfur dioxide emissionsin the region by 8 to 12 million tons below actual1980 emission levels by the early 1990’s. IndividualStates would be allocated reductions through for-mulas based primarily on utility sulfur dioxideemission rates. Variations on this approach includedesignating a smaller, 22-State control region, des-ignating a 48-State control region, establishing atrust fund to pay some or all of the costs of emis-sions reductions, allocating reductions by consider-ing both utility and industrial emissions, and allow-ing 2 tons of nitrogen oxides emissions to besubstituted for each required ton of sulfur dioxideemissions reductions.

The bills vary in their treatment of new sourcesof emissions; some allow emissions from post-1980sources to increase total emissions in the region,while others require further reductions to offset newemissions. Options for controlling the sources of

105


transported air pollutants are discussed under ‘ ‘Ap-proach A: Mandating Emissions Reductions. ”

Bills addressing other aspects of transported pol-lutants have also been introduced during the 97thand 98th Congresses. For example, several billswould tighten nitrogen oxide emission standardsfor utility and mobile sources, accelerate develop-ment of innovative pollution control technologies,and provide Federal funding to lime acid-alteredbodies of water that have ceased to support somefish species. Alternatives for implementing the lastof these proposals are presented under ‘‘ApproachB: Liming Lakes and Streams. ”

Bills have also been introduced to amend the in-terstate and international provisions of the CleanAir Act. Clarifying the scope of these provisionscould aid States, EPA, and affected foreign coun-tries in dealing with transboundary pollution prob-lems other than acid deposition—in particular, mid-distance transport of air pollution currently regu-lated under the act. Options for amending thesesections of the current law are presented under“Approach D: Modifying the Existing Interna-tional and Interstate Sections of the Clean Air Act.

APPROACHES AND OPTIONS

This section presents congressional options foraddressing acid deposition and other transportedair pollutants, grouped according to four major ap-proaches:

●

●

●

●

Approach A: Mandating emissions reductions tofurther control the sources of transportedpollutants;Approach B: Liming lakes and streams to mitig-ate some of the effects of acid deposition;Approach C: Modifying the Federal acid depo-sition research program to provide more timelyguidance for congressional decisions; andApproach D: Modifying existing sections of theClean Air Act to enable-EPA, States, and coun-tries to more effectively address transported pol-lutants other than acid deposition.

Congress could choose to adopt some or all of theseapproaches in considering clean-air legislation. Acomprehensive strategy for addressing transportedair pollutants might well include options from allfour approaches. The four are described below,along with their respective options.

APPROACH A:Mandating Emissions Reductions

Discussion:

Additional legislated emissions reductions couldrange from modest, possibly interim, reductions tooffset expected future emissions growth, to large-

scale control programs. In choosing an appropri-ate program, Congress will need to weigh the risksof potential resource damage against those of inef-ficient control expenditures. These decisions arecomplicated by the scientific uncertainties, disagree-ment over values, and distributional issues dis-cussed throughout this report.

Mandating further emissions reductions wouldrequire Congress to make a number of interrelatedchoices. These include decisions about which pol-lutant emissions to reduce, from what source re-gions, by how much, and over what time period.Congress would also need to choose specific policymechanisms to implement the reductions, allocatetheir costs, and address undesired secondary con-sequences of emissions reductions.

OTA has outlined a series of eight control-policydecisions that must be made in order to design aciddeposition control legislation. These are summar-ized below, to provide the framework for consider-ing three representative emissions control optionspresented at the end of this section. Chapter 7 dis-cusses the eight control-policy decisions in greaterdetail, and presents options available to Congressunder each decision area.

● Which Pollutants Should Be Further Con-trolled?

Three pollutants are potential candidates: sulfurdioxide, nitrogen oxides, and hydrocarbons. Sulfurdioxide and nitrogen oxides (and their transforma-

Ch. 6—Policy Options . 107

tion products) are major sources of acidity to theenvironment. In the Eastern United States, sulfurcompounds annually contribute about twice asmuch acidity to precipitation as nitrogen com-pounds. Moreover, during most times of the year,plants use much of the deposited nitrogen as a nu-trient, making sulfur compounds responsible for astill larger share of acidity reaching water bodies.For these reasons, any control program for the East-ern United States would have to include provisionsfor reducing sulfur dioxide emissions.

If desired, additional resource protection can beachieved by also mandating reductions of nitrogenoxides emissions. Nitrogen oxides emissions are ex-pected to increase more rapidly over the next fewdecades than sulfur dioxide emissions. Duringspringtime snow melt, both sulfur and nitrogencompounds accumulated in the snow over the win-ter can reach water bodies unimpeded. In the West,nitrogen compounds may contribute as much as ormore acidity to precipitation than do sulfur com-pounds, and thus should be considered if a nation-wide control program is enacted.

Hydrocarbons can affect the geographic distri-bution of acid deposition. The atmospheric chem-istry involved, however, is not sufficiently under-stood to ‘‘fine-tune’ a sulfur dioxide or combinedsulfur dioxide and nitrogen oxides control programwith hydrocarbon emissions control.

c How Widespread Should a Control ProgramBe?

Four regions are potential candidates for emis-sions reductions, starting with the NortheasternUnited States and expanding southward and west-ward: 1 ) the approximately 2 l-State Northeasternregion receiving the greatest levels of acid deposi-tion; 2) a 31-State region (all States east of andbordering on the Mississippi River), incorporatinga band of States around the region of greatest depo-sition; 3) a 37-State region, including all States eastof the Rocky Mountains; and 4) the contiguous 48States.

About 65 percent of the Nation’s sulfur oxidesand 45 percent of its nitrogen oxides are emittedin the 2 l-State region east of the Mississippi andnorth of and including Tennessee and North Caro-lina. About 85 percent of the Nation’s sulfur ox-

ides and 65 percent of nitrogen oxides are emittedin the 31-State region.

● What Level of Pollution Control Should BeRequired?

The congressional choice of how much pollutionto eliminate must, of necessity, be based on incom-plete information. Expected resource-protectionbenefits, control costs, and other potential risks andbenefits are concerns that must be balanced to de-termine the socially desirable level of emissions re-ductions. The costs of various levels of control arerelatively well-known, but only a few referencepoints are available for assessing the potential ben-efits of further emissions control.

An acid deposition control program could rangein size from one that would prevent future increasesin emissions—eliminating about 2 to 3 million tonsof the 22 million tons of sulfur dioxide emitted an-nually in the Eastern 31-State region to offset ex-pected growth through the year 2000—to one thatwould achieve large-scale reductions below currentlevels. Eliminating about 11 to 12.5 million tonsof sulfur dioxide per year might be considered theupper end of this range; mandating even largeremissions reductions would require most existingutilities to adopt more stringent emissions controlsthan those governing emissions sources subject toNSPS.

Reducing sulfur dioxide emissions in the east-ern United States by 8 to 10 million tons per yearbelow current levels would probably protect all butthe most sensitive aquatic resources in many areasreceiving high levels of acid deposition, but not inthose areas receiving the greatest amounts. Risksof damage to sensitive forests, materials, and cropswould also be reduced. In addition, airborne fine-particle levels would be lower, improving visibilityand reducing risks to human health. Such reduc-tions— near the upper end of the feasible range—would cost about $3 to $6 billion per year, depend-ing on the design of the control program. Costswould rise steeply if greater resource protectionwere desired; both control costs and the amountof resource protection would be less with loweremissions reductions.

About 2 to 5 million tons of sulfur dioxide emis-sions per year could probably be eliminated for


about $1 billion per year or less. This would cer-tainly be enough to prevent emissions from increas-ing through 2000 (i. e., offset expected industrialand utility growth), and could potentially decreaseemissions 2 to 3 million tons below current levelsby 2000. Risks of damage to sensitive aquatic re-sources, forests, agriculture, materials, and healthwould be reduced, but at present it is impossibleto gauge by how much.

Congress could either specify the level of emis-sions reductions directly or state the policy goalsto be met and instruct the Administrator of EPAto set the level of reductions.

● By What Time Should Reductions Be Re-quired?

A congressional decision to require further con-trols is likely to take at least 6 or 7—possibly 10or more—years to implement. Extensive Federal,State, and source-level planning will be requiredeven before the contract and construction stagesbegin. Smaller levels of emissions reductions, ifachieved primarily through fuel switching, mightbe implemented somewhat more quickly.

Alternatively, Congress might decide to wait forguidance from the National Acid Precipitation As-sessment Program, thereby delaying controls an ad-ditional 4 to 6 or more years. Additional risks ofresource damage would result from such a delay,but current understanding does not allow theirquantification.

Congress could also direct Federal and State of-ficials to begin control planning now, but make thecontract and construction phase conditional on theresults of further research. Control programs couldbe modified or specific implementation planschanged as late as about 2 years before the com-pliance date, at which point major construction ex-penditures would have to begin.

● What Approach to Control Should BeAdopted?

Existing environmental regulations focus oneither: 1 ) pollution sources, i.e., directly regula-ting total emissions or emission rates from sourcesor regions; or 2) pollutant exposure, i.e., settinggoals or standards to limit human or environmentalexposure to pollutants.

The first approach, a source-oriented control pro-gram, could be implemented now, either by directlylimiting emissions or emission rates or by requir-ing the use of control technologies.

Controlling acid deposition through the secondapproach would require a well-developed under-standing of the transport, transformation, fate, andeffects of pollutants. Such knowledge—accurateenough for a receptor-based regulatory program—does not yet exist for acid deposition. By the mid-1990’s, however, models and similar tools mighthave accuracy sufficient for designing a receptor-based approach on a regional scale (i.e., with emiss-ions reductions allocated to State-size or largerareas).

. How Should Emissions Reductions Be Al-located?

Congress could limit emissions directly by:1) mandating a reduction formula that applies toall or a subset of individual sources within a con-trol region; or 2) allocating emissions reductionsto States, allowing the States to allocate source-levelcutbacks within their borders. Alternatively, Con-gress could direct EPA to allocate emissions reduc-tions to meet specified congressional goals.

Policy considerations pertinent to designing anallocation formula include: “Who is to gain thebenefit of resource protection and who is to bearthe burden of reductions?” and ‘‘How adminis-tratively and economically efficient is the plan?’Most legislative proposals to date have been basedon: 1 ) emission rates (i. e., sulfur dioxide emittedper quantity of fuel burned) in order to reduce emis-sions most cost effectively, and 2) utility emissionsonly, to reduce the administrative complexity ofdetermining each State’s share. While fairly accu-rate data are available on the 70 percent of East-ern sulfur dioxide emissions from utilities, emis-sions from other sectors are difficult to estimateaccurately.

Chapter VII and appendix A review a numberof allocation approaches, some based on total Stateemissions, some on a State’s utility emissions alone.Each allocation formula varies in the resulting geo-graphic pattern of emissions reductions, total costsfor equivalent regionwide reductions, and admin-istrative complexity.

Ch. 6—Policy Options ● 109

● Who Pays the Costs of Emissions Reductions?

Allocating reductions and allocating their costsare two distinct issues. Congress could: 1) requireaffected sources to pay the full costs of control, or2) create a fee or tax to spread control costs overa larger group than those required to reduce emis-sions. While the former approach is consistent withthe current Clean Air Act, the latter recognizes thedifficulty of linking emissions from any given sourceto damage in areas far removed.

● What Can Be Done to Mitigate Employmentand Economic Effects of a Control Policy?

Cutting back sulfur dioxide emissions could sig-nificantly affect two industries: coal mining andelectric utilities. If utilities and other emitters areallowed to switch to lower sulfur fuels= often a cost-effective means of reducing emissions—some pro-duction will shift from regions producing high-sulfur coal to those producing low-sulfur coal, withassociated employment and economic effects. Em-ployment shifts might be reduced by requiring emit-ters to install control technologies designed for usewith high-sulfur coals, or by restricting coal pur-chases according to location of coal supply. Sucha program might increase total control costs con-siderably, however. For reductions in the range of8 to 10 million tons per year, costs might rise by25 to 50 percent, depending on the specifics of theplan. Special compensation to workers or communi-ties affected by the new law would also be possible.

Those utilities that choose (or are required) touse control technologies for meeting major emis-sions reduction requirements would need to raiseadditional capital to build such equipment. Con-gress could reduce financial pressures on utilitiesby establishing a tax to help pay for the costs ofcontrol, or by funding research and demonstrationprojects to develop potentially cheaper control tech-nologies.

Options:

Congress could design a control program by se-lecting alternatives from each of the eight decisionareas summarized above. Obviously, many com-binations are possible; the three options presentedbelow represent portions of the decisionmakingspectrum ranging from modest reductions to large-

scale control programs. Each strikes a different bal-ance between the risks of future resource damageand the risks of inefficient pollution control.

Option A-1: Mandate Small-Scale Emissions Re-ductions.

A small-scale program would logically focus oncontrolling sulfur dioxide emissions—the majormanmade acidic pollutant in the Eastern UnitedStates—within the broad region receiving greatestlevels of acid deposition. Eliminating about 2 to 5million tons of sulfur dioxide emissions per yearwould be feasible within about 5 to 7 years fromthe date of passage. Reductions of this magnitudewould probably hold acid deposition levels aboutconstant, or result in modest declines, through theend of the century.

The control region might encompass either theNortheastern 21 States or the 31 Eastern States.All States could be required to eliminate an equalpercentage of emissions (e. g., 10 to 20 percent),or be allocated reductions based on emission rates(e.g., an emission rate limitation of between 2.5and 4.0 lb of sulfur dioxide per million Btu of fuelburned). Each State might be responsible for deter-mining which sources to control and how much pol-lution to eliminate from each source. Alternatively,Congress could mandate emission rate limitationsfor all sources emitting in excess of a specified rate.

Other possibilities for modest emissions reduc-tions include mandatory coal washing for certaintypes of coal, or requiring selected sources to useemissions control technology. The former mighteliminate up to about 2 million tons of sulfur di-oxide per year, while the latter approach could bedesigned to achieve cutbacks of any desired mag-nitude in the range of 2 to 5 million tons per year.Either of these last two approaches would minimizelosses of high-sulfur coal production and relatedemployment, but would increase the cost of control.

A small-scale program could be accomplished forunder $1 billion per year (1982 dollars) for a cut-back of 2 to 3 million tons per year of sulfur di-oxide, and for about $1 to $1.5 billion per year forabout a 5-million-ton reduction, Costs could range,however, as high as $2.5 billion per year for a 5-million-ton program requiring the use of emissionscontrol technology. Congress could require the


sources allocated emissions reductions, and theircustomers, to pay the cost of reductions directly,or spread the costs more widely by establishing afee on electricity or pollutant emissions.

Option A-2: Mandate Large-Scale Emissions Re-ductions.

Many of the acid deposition control proposalsintroduced during the 97th and 98th Congresseswould reduce sulfur dioxide emissions by 8 to 12million tons annually. Several include reductionsin nitrogen oxide emissions as part of the controlprogram as well.

As discussed in chapter 5, large-scale sulfur di-oxide emissions reductions (8 to 10 million tons an-nually below 1980 levels) would probably protectall but the most sensitive lakes and streams in manyareas receiving high levels of acid deposition. Areascurrently receiving the highest levels of acid depo-sition (e. g., Western Pennsylvania) would also ben-efit, but to a lesser extent—a larger proportion oftheir aquatic resources might still be at risk.

The control region for a program of this scalemight include the 31 Eastern States, all States eastof the Rocky Mountains, or the 48 contiguousStates. If the desired control region extends to theWest, nitrogen oxides emissions become increasing-ly important, as nitrogen oxides contribute rel-atively larger shares of precipitation acidity in theWest than in the East.

A large-scale program would require about 8 to12 years to implement. By choosing a longer com-pliance time (e. g., 12 years), Congress could allowgreater opportunity for modifying control plans toincorporate future research results or newly devel-oped control technologies. The program could bealtered or implementation plans changed untilabout 2 to 4 years before the scheduled compliancedate. Although Federal, State, and source-level per-sonnel would have spent considerable time and ef-fort planning the program, few contracts wouldhave been let before that time, and major capitalexpenditures would not have occurred. The pro-gram could either have a single compliance dateor be implemented in phases, beginning with a firstphase similar to option A-1.

Emissions reductions can be allocated to Statesin many ways. Major alternatives are discussed in

detail in chapter 7 and appendix A. Each formulahas distributional implications—for both who re-duces and who receives the benefits of the reduc-tions. In addition, the formulas vary in administra-tive complexity. For example, many recent acidrain control proposals have been based on utilityemissions in excess of a specified rate— 1.2 or 1.5lb of sulfur dioxide per million Btu of fuel burned.This is perhaps the least expensive approach for re-ducing regional emissions, but it concentrates muchof the required reduction in the Midwest. Such aprogram would cost from $2 to $5 billion per year,depending on the stringency and design. Offset-ting future emissions growth, if required, might costan additional $1 to $2 billion per year.

Because such an approach would be costly forelectricity consumers in some States, Congressmight want to create a trust fund to finance partof the program. A trust fund to pay for capital costsassociated with emissions control technology wouldalso assist an already capital-short utility industry.The trust fund could be based either on pollutantemissions or on a surrogate, such as electricity gen-erated or fuel deliveries.

Paying part of the costs of pollution control tech-nology through a trust fund (but not reimbursingfuel-switching costs) would also help to preventlosses in high-sulfur coal production and employ-ment. However, encouraging the use of controltechnology through a trust fund, or mandating itsuse, would increase total control costs and reducepotential gains in Western coal production.

Option A-3: Mandate an “Environmental Qual-ity” Standard.

Rather than mandating specific emissions reduc-tions, Congress could direct the Administrator ofEPA to develop a control plan to achieve congres-sionally specified environmental quality goals (in-cluding cost considerations, if desired). Though atpresent scientists cannot accurately predict thebenefits of various levels and regional patterns ofemissions reductions, such capability might be pos-sible by 1995 or 2000. A control program could thenbe based in part on a better understanding of therelationship between emissions and depositionamong State or multi-State regions. It is unlikely,however, that scientists will be able to relate emis-



The coal from this Ohio mine is about to be“washed’ ’-physically cleaned—to remove sulfur, ash,and other impurities. About one-third of the coal burnedby Eastern and Midwestern utilities is washed, therebypreventing about 2 million tons of sulfur dioxideemissions each year. An additional 2 million tons couldbe eliminated by more extensive use of this technique

#sions from single sources to small receptor areasfor the foreseeable future.

A concerted 10- to 15-year effort might producea control program either less expensive or more ef-fective than that outlined in option A-2. However,the longer time required to achieve compliance—it would be about 2005 to 2010 before the plan couldbe implemented—would also permit additional re-source damage.

Congress might choose to precede such a pro-gram with mandated, small-scale emissions reduc-tions, such as presented in option A-1. The reduc-tions required under option A-1 are unlikely to

Photo credit Ted Spiegel

At the Bruce Mansfield powerplant in Pennsylvania,lime is destined for use in the plant’s flue-gas“scrub ber.” The lime is mixed with water and sprayedover the exhaust gas, removing over 90 percent of thesulfur dioxide that otherwise would have been emitted.The sulfur-laden lime slurry is discharged as a wetsludge that must be disposed with care to preventwater contamination. Newer technologies promise

easier waste disposal or the possibility ofreclaiming a usable product

exceed those eventually required under the envi-ronmental quality standard; at a minimum, theywould prevent acid deposition levels from increas-ing before the remainder of the plan is imple-mented.

APPROACH B:Liming Lakes and Streams.

Discussion:

OTA estimates that about 3,000 lakes and 23,000miles of streams in the Eastern 31 States are ex-


tremely sensitive to acid deposition or are alreadyacid-altered. Damage to or elimination of fisherieshas been documented in several regions of easternNorth America. Any congressional decision to re-duce emissions that contribute to acid depositionwould take at least a decade to implement, so itmight be many years before lakes could be seen toimprove. Moreover, while a significant portion ofthese lakes and streams would benefit from substan-tial emissions reductions, some might still notimprove sufficiently to ensure support of self-sustaining fish populations.

Several forms of chemical treatment have beenused for reducing acid-related damages to sensitiveaquatic ecosystems. Most involve neutralizingacidic waters and sediments with large quantitiesof alkaline substances. One technique-temporarilyrestoring the buffering capacity of a lake or streamwith lime-often improves water quality sufficientlyto maintain reproducing fisheries. Treating terres-trial ecosystems has also been proposed; however,while alkaline materials are commonly added toacidic agricultural soils, little experimentation hasoccurred on forested ecosystems. Counteractingsurface-water acidity cannot substitute for control-ling transported pollutants at their source. Suchmeasures can, however, provide short-term protec-tion to some currently altered resources, by treatingone of the symptoms of acid deposition.

Not all lakes and streams respond sufficiently toliming to maintain reproducing fisheries. In partic-ular, lakes with short water-retention times (i. e.,where water remains in the lake for less than ayear), and streams with great variations in flow,are very difficult to lime effectively. Historically,such additional factors as demonstrated ability tosupport a significant, viable fishery, recreationalpotential and public access to waters, and degreeof acidification have been used to guide the choiceof liming targets. For those lakes where liming iseffective, a single application of lime will restorebuffering capacity for a period of 3 to 5 years; toprevent reacidification, lime must be reappliedevery few years.

While liming has enhanced fish survival in anumber of lakes and streams, its long-term impli-cations for the food chain on which fish depend isuncertain. Scientists do not know how periodic

changes in water body chemistry through limingwill affect aquatic ecosystems over the long term.Little research has been done on alternative meas-ures or on minimizing adverse impacts of liming.Increased Federal and State efforts to develop andtest aquatic treatment methods could help to in-crease availability of fishing recreation in highlysensitive areas over the next few decades.

Liming has been effective in counteracting sur-face-water acidification in parts of Scandinavia,Canada, and in the United States in New York andMassachusetts. The most extensive U.S. programwas begun by the New York State Department ofEnvironmental Conservation in 1959. It initiallytargeted small, naturally acidic ponds in heavilyused recreational areas, and expanded to treatingselected acidified lakes with significant potential tosupport recreational fishing during the mid-1970’s.The program is quite small-only about 60 lakesin total (covering about 1,000 acres) have beentreated since its inception. Following liming, wa-ter quality has improved at a number of lakes andponds, and self-propagating sport fishing popula-tions have been reintroduced and maintained.

Costs for liming ponds and lakes under the NewYork State program have ranged from approx-imately $30 to $300 per acre for each application,depending on the size and accessibility of the wa-ter body. A recent study of liming requirementsin the Adirondack Mountain region of New YorkState estimated that a 5-year program for limingseveral hundred acidified lakes in the region couldbe implemented for between $2 and $4 million peryear, depending on the desired buffering level.1

This does not include the costs of restocking fishor continuing monitoring of lake water chemistryand biology, which would increase the cost con-siderably.

Federal funds have been available since 1950under the Dingell-Johnson Act to aid States in car-rying out “projects having as their purpose therestoration, conservation, management, and en-hancement of sport fish and the provision for publicuse and benefits from these resources. A IO-per-cent excise tax on the wholesale cost of fishing tackle

‘Frederic C. Menz and Charles T. Driscoll, ‘‘An Estimate of theCosts of Liming To Neutralize Acidic Adirondack Surface Waters,Contribution #13 of the Upstate Freshwater Institute, June 1983.


Photo credit: New England Interstate Water Pollution Control Commission

its ability to neutralize incoming acids, thereby preventing harm to aquaticAdding lime to a lake can temporarily restorelife. Lakes near roads can often be limed by boat (shown above); for others, large quantities of lime must be transported

by aircraft. Not all lakes and streams can be effectively limed

provides revenues under the act. States are reim-bursed for 75 percent of their expenditures on proj-ects approved by the U.S. Fish and Wildlife Serv-ice (FWS). About 60 percent of total Dingell-John-son funds are currently used by States for survey,management, and research activities.

Dingell-Johnson funds have been used in the pastto support individual liming projects; they providedstartup money to the New York State Departmentof Environmental Conservation’s liming programfrom 1959 to 1965. FWS program staff suggest thatStates able to demonstrate the potential cost-effec-tiveness of liming to meet a specific acidificationproblem could presently receive Federal funds forliming and follow-up monitoring.

A proposal to expand the coverage of the Dingell-Johnson excise tax to include additional recreationalfishing equipment is currently before the Congress(H.R. 2163); if passed, the proposal would approx-imately double receipts collected under the act. Ex-panding the fund has been advocated as a meansof allowing States to keep up with the costs of sportfish management in an era of rising costs and de-clining State resources. Such a move might also en-courage States to include mitigation efforts amongtheir project proposals for Federal funding.

Lack of funding for liming projects, however,may not be the most important impediment to ex-panding mitigation activities. Improving our cur-rent ability to restore or protect acid-altered waters


will require extensive monitoring of the chemicaland biological changes that follow liming applica-tions. Until considerably greater resources are al-located to studying the ways in which liming af-fects various types of water bodies, the results ofeach application will remain uncertain.

Federal research on aquatic treatment methods,as specified in the Acid Precipitation Act of 1980,began in 1982 under the direction of the FWS. Todate, the Federal research effort has produced atechnical report on liming, and an agenda of fur-ther research needs determined by participants inan international mitigation conference. Total Fed-eral funding for these efforts in fiscal year 1983amounted to $225,000.

The administration recently proposed about $5million dollars for liming research for fiscal year1985. Such funding increases would permit re-searchers to study the effects of liming on waterbodies with differing geological, chemical, andbiological characteristics throughout the EasternUnited States, and to investigate the effectivenessof alternative mitigation measures.

Options:

Specific options available to Congress for Fed-eral support of research and implementation oftechniques to mitigate some of the effects of aciddeposition are described below.

Option B-1: Expand Federal Research on Aquatic(and Other) Treatment Methods.

Although researchers at the FWS have begun toinvestigate the effects of a few mitigation tech-niques—primarily liming—on aquatic life in acidi-fied lakes, levels of funding are low and permit onlya few research projects to be undertaken each year.Additional funding—for example, at the $5 mil-lion per year level proposed by the administra-tion— would allow the FWS program to expand itscoverage to a variety of lakes and streams beingtreated under differing geological, geographic, andbiological conditions. Such expansion would aid theFWS in developing guidelines on liming and othermitigation techniques for use by States, local com-munities, and private interests.

Further research on treatment methods for ter-restrial ecosystems and watersheds could also be un-dertaken through either the Forest Service or FWS.

Congress could provide additional funding specific-ally for mitigation research, or direct the Inter-agency Task Force (responsible for directing Fed-eral acid deposition research under the AcidPrecipitation Act of 1980) to allocate a greater por-tion of its existing budget to such activities.

Option B-2. Expand Federal-State Cooperative Ef-forts for Treating Acidified Surface Waters andAssessing Results.

While costs for liming acidified surface watersare relatively modest, assessing the effectiveness ofthese treatments can be much more expensive thanliming itself, and requires substantial technical ex-pertise. Federal funds to support liming and follow-up monitoring are potentially available under theexisting Dingell-Johnson Act, although States cur-rently carry out very little mitigation-related workwith these funds.

Congress could instruct the FWS to provideguidelines to States on requirements for qualify-ing for Dingell-Johnson funds to treat acidified sur-face waters. Congress could also broaden the act’sexcise tax base to provide States with additionalfunds as an indirect means of encouraging State-level mitigation efforts. Alternatively, Congresscould establish a new Federal-State cooperative pro-gram specifically to support surface-water treatmentand subsequent monitoring activities.

Option B-3: Establish Demonstration Projects forAcidified Water Bodies on Federal Lands.

The Federal Government has extensive landholdings in areas of the Eastern United States thatare considered sensitive to the effects of acidprecipitation, including the White Mountain Na-tional Forest in New Hampshire, the Green Moun-tain National Forest in Vermont, and the AlleghenyNational Forest in northwestern Pennsylvania.Congress could direct the Forest Service and theFWS to establish cooperative demonstration pro-grams to treat selected lakes and streams on Fed-eral lands with significant recreational fishingpotential or heritage fish populations, and subse-quently monitor their chemical and biological re-sponses. Funding could be provided through theexisting interagency acid deposition research pro-gram to fund FWS monitoring activities, or be al-located to the Forest Service specifically for surface-water mitigation.


APPROACH C:Modifying the Federal Acid

Deposition Research Program

Discussion:

Under the Acid Precipitation Act of 1980 (TitleVII of the Energy Security Act of 1980—PublicLaw 96-294), Congress created an InteragencyTask Force* to conduct a comprehensive 10-yearnational assessment program on acid deposition.The goals of the research program are:

● to identify the causes and sources of acid pre-cipitation,

● to evaluate the environmental, social, and eco-nomic effects of acid precipitation, and

● to determine the effectiveness of actions avail-able to control the emissions responsible foracid deposition, and mitigate harmful effectsof acid deposition on receptor systems.

The act requires the Task Force to submit an-nual reports to the President and Congress, describ-ing the progress of the research program and rec-ommending actions that Congress and appropriateFederal agencies might take to alleviate acid depo-sition and its effects.

The Task Force presented a detailed researchprogram—the National Acid Precipitation Assess-ment Program (NAPAP)—to Congress in June1982. NAPAP outlines the general strategy fororganizing the research effort, using 10 workinggroups organized by scientific discipline. Theseworking groups are composed of program managersand experts from the Federal agencies participatingin the research effort. Areas of responsibility foreach of the 10 working groups are outlined in table5.

The plan specifies an ambitious research pro-gram requiring extensive coordination amonggroups. If the research continues on schedule, theTask Force expects to develop by 1985 preliminaryestimates of current and potential resource dam-age due to acid deposition. It plans to use this in-formation, along with models developed by the task

● The Interagency Task Force is composed of heads and represent-atives of various agencies and national laboratories and four membersappointed by the President.

Table 5.—Organization of the National AcidPrecipitation Assessment Program

Task Group A: Natural SourcesCoordinating agency—NOAA. Responsibility—assess the

effect of natural emissions on acid deposition.

Task Group B: Man-Made SourcesCoordinating agency—DOE. Responsibilities-refine exist-

ing sulfur dioxide and nitrogen oxides emissions estimates,and develop improved models to estimate future sulfur andnitrogen emissions from major polluting sectors.

Task Group C: Atmospheric RecessesCoordinating agency—/VOAA. Responsibilities—examine

the link between emission of pollutants and acid deposition.

Task Group D: Deposition MonitoringCoordinating agency—DO/, Responsibilities—develop a

long-term national program to monitor the chemical composi-tion of acid deposition (both wet and dry), and improve thereliability and accuracy of sampling techniques.

Work Group E: Aquatic EffectsCoordinating agency—EPA. Responsibilities—1) assess

the resources at risk in the United States from acid deposi-tion, 2) study the mechanisms by which biological damagecan occur, 3) evaluate the risk of acidifying drinking watersupplies through acid deposition, and 4) analyze strategiesto mitigate the harmful effects of acid deposition.

Task Group F: Terrestrial EffectsCoordinating agency—DOA. Responsibilities—assess the

nature and extent of the effects of acid deposition on crops,forests, and noncommercial terrestrial ecosystems.

Task Group G: Effects on MaterialsCoordinating agency—DOI. Responsibilities—assess the

effect of air pollution— in particular, acid deposition—on arange of economically important materials and historic mon-uments and structures.

Task Group H: Control TechnologiesCoordinating agency—EPA. Although this group was re-

ferred to in the National Plan of June 1982, the latest draftoperating plan does not contain a work statement for the con-trol technology group, nor does it specify deliverable reports.

Task Group 1: Assessments and Policy AnalysisCoordinating agency—EPA. Responsibilities—integrate

the research results of the other work groups, and carry outcost-benefit analyses to assist the Task Force in formulat-ing guidance for policy makers.

Task Group J: International ActivitiesCoordinating agency–DOS. Responsibility–ensure that

the National Program is coordinated with ongoing U. S.-Canadian and other international activities related to aciddeposition.

SOURCE: Office of Technology Assessment, based on information from the Na-tional Acid Precipitation Assessment Program, June 1982; and the inter-agency Task Force on Acid Precipitation, January 1982.

groups, to produce integrated, policy-related assess-ments in 1987 and 1989. The 1985 damage esti-mates are expected to be used primarily for redirect-ing or fine-tuning the further research efforts. Sincethe planned assessment activity calls for extensivemethods development and data collection before


policy analysis begins, NAPAP does not anticipate‘ ‘useful guidance to policy makers’ until 1987 to1989.

Many members of Congress and public interestgroups have expressed concern about the length oftime projected for NAPAP to produce a useful pol-icy assessment. While such a research plan mightproduce more accurate analyses than those resultingfrom a shorter effort, many consider waiting until1989 for this level of refinement unacceptable. Sev-eral bills introduced in the 97th and 98th Con-gresses proposed to accelerate the originally planned10-year program to a 5-year effort.

Such a legislated acceleration could seriouslycompromise the scientific credibility of the results.Substantial time and effort would be needed to re-design the research schedule. (The present programrequired 2 years to plan. ) Many currently plannedresearch efforts are designed to build on results fromwork presently under way; these projects wouldhave to be significantly redesigned so that they

could begin more quickly. Moreover, many of thecurrently planned efforts simply could not be ac-celerated, even if additional funding were provided.

For many field experiments on lakes, forests, andsoils, doubling the number of experiments in oneyear usually cannot substitute for 2 consecutiveyears of research. It is doubtful that a new genera-tion of atmospheric transport models could be de-veloped within a few years. Such modeling effortsinvolve years of trial and error—and require sev-eral more years of monitoring data to validate theresults over a range of climatological conditions,

A strong, continuing research program is a nec-essary part of any strategy Congress might chooseto address the problem of acid deposition. Severalmodifications, however, might make the currentprogram more responsive to congressional informa-tion needs.

If a decision on an emissions control programis delayed for several years, Congress could estab-


lish a new, separate assessment activity investigat-ing a range of legislative options. Findings fromongoing Federal research could then be incorpo-rated into policy guidance more quickly than isplanned under the present timetable, without dis-turbing the longer term Federal plan.

If Congress acts to control acid deposition, theprogram could be redirected to support implemen-tation and evaluation of the legislation. Concernshave been raised within the scientific communitythat if control legislation is enacted, important re-search efforts might not be adequately funded overthe long term. At least 5 years would elapse betweenthe time legislation is passed and emissions reduc-tions are achieved. Continued research in a numberof fields would be important for further evaluationof the control strategy throughout this period, andfor designing and implementing the chosen con-trol program into the 1990’s.

Many within the scientific community are alsoconcerned over the breadth of the research pro-gram, regardless of whether a control program isadopted. NAPAP’s enabling legislation focuses onacid deposition. However, researchers have foundthis emphasis to be restrictive in two ways. Sev-eral resources—notably forests, crops, and materi-als-are exposed to multiple air pollutants; under-standing the effect of any single pollutant requiresresearch on all. Similarly, the potential benefits ofemissions reductions are not limited to those asso-ciated with lowered levels of acid deposition.

For example, reductions of sulfur dioxide emis-sions will improve visibility and lower concentra-tions of airborne fine particles. It is difficult, how-ever, to coordinate the various existing Federal air-pollution research programs addressing these prob-lems with the NAPAP effort. The innovative re-search management framework established by theAcid Precipitation Act of 1980 could serve as thebasis for a more encompassing Federal air-pollutionresearch effort.

Options:

Specific options available to Congress for modi-fying the current acid deposition research programare described below.

Option C-1: Establish a “Two-Track” ResearchProgram.

Concurrent with the existing research program,Congress could mandate a separate policy assess-ment—with separate funding—to be completed bya specified date. The current Plan could remain in-tact, although some modifications might be nec-essary to provide needed information to the policyassessment effort. Such a ‘‘two-track’ programcould provide Congress with timely policy guid-ance, without jeopardizing the longer term researchcurrently under way.

Congress could require the assessment to eval-uate a series of control alternatives within 2 or 3years. Though the evaluation would have to bebased on incomplete information (as might the cur-rently planned integrated assessment), a commonset of alternative scenarios would be available forpolicymakers to consider. This option would estab-lish a research effort similar to this OTA assess-ment—a description of plausible outcomes fromvarious policy alternatives-but with the benefit ofa few more years of data and greater resources.

Such a research effort would use a consistent setof assumptions and models to evaluate:

●

●

●

●

●

the costs of each control program,secondary effects of control (e. g., shifts in coal-mining related employment),expected deposition reductions (using severalcurrently available atmospheric transportmodels),other air quality benefits (e. g., improvementsin visibility and air concentrations for fine par-ticulate), andresource benefits (e. g., percent of land areareceiving deposition at or below levels thoughtto be safe for sensitive aquatic resources).

EPA (which currently coordinates the Assess-ments and Policy Analysis Task Group), might bedesignated to conduct the short-term evaluation,or another organization (e. g., the Council on Envi-ronmental Quality) might be chosen if two sepa-rate assessments are desired. One (or a consortium)of the national laboratories or the National Acad-emy of Sciences are possible candidates from out-side the Federal agencies.


Option C-2: Redirect the Research Program If aControl Program Is Legislated.

The Acid Precipitation Act of 1980 does not pro-vide for modifying the research program if a con-trol program were enacted. Continued research—with some redirection—would serve several pur-poses if control legislation were passed. Researchresults could be used in designing and implement-ing the details of the chosen control strategy throughthe 1990’s. Because it might take about a decadeto implement, the control program would requirevigorous research support to reflect the most cur-rent, rather than 10-year-old, scientific informa-tion. In addition, the research program could pro-vide data to evaluate the effectiveness of thelegislation after passage.

The Interagency Task Force is already examin-ing necessary changes to the research plan to beresponsive to potential control legislation. Congresscould direct the Task Force to modify the programto provide information appropriate for regulatorydecisionmaking.

Option C-3: Broaden the Research Program ToAddress Other Transported Air Pollutants.

The Acid Precipitation Act of 1980 establishedan innovative, interagency research program toevaluate the effects of acid deposition and the ef-fectiveness of means available to control it. The ef-fects on many resources, however, are difficult todetermine without active research on other pollut-ants. Similarly, the benefits of reducing pollutantemissions are not confined to those associated withreduced levels of acid deposition.

Congress could use the existing interagencystructure and broaden its mandate to include re-search on other air pollutants. For example, re-search showing forest productivity declines in theUnited States and West Germany has led scientiststo become concerned about the combined stressfrom acid deposition, ozone, and heavy-metal depo-sition. Broadening the research program could pro-vide useful information to Congress for evaluatingboth current proposals to control acid depositionand, perhaps more importantly, future modifica-tions to the Clean Air Act that might be desirablefor addressing the more general problem of trans-ported air pollutants.

APPROACH D: ModifyingExisting International and Interstate

Sections of the Clean Air Act

Discussion:

The 1977 Amendments to the Clean Air Actadded provisions to regulate interstate and inter-national air pollutant effects through the existingcontrol mechanism of state implementation plans(SIPS). Section lo requires SIPS to pre-vent a State’s emissions from causing violations ofair quality standards in other States. * The sectionfurther prohibits EPA from approving a SIP or aSIP revision that causes violations of National Am-bient Air Quality Standards (NAAQS) in anotherState. Currently, however, this section applies onlyto air concentrations of pollutants for whichNAAQS exist and therefore does not directly ad-dress acid deposition.

EPA has not issued regulations interpreting sec-tion 110(a)(2)(E) since it was enacted in 1977; how-ever, agency reviews of potential interstate pollu-tion violations to date have been limited to theportion of the SIP undergoing revision. When pro-posed SIP revisions would relax an individualsource’s emissions limitations, EPA assesses onlyhow the source’s proposed emissions increase wouldaffect interstate air quality. EPA also takes the posi-tion that there are no adequate modeling tools toassess the long-range effects of either individual ormultiple sources.

Several States and other petitioners have filed suitin the U.S. Circuit Courts to challenge EPA’s ap-proval of SIP relaxations, claiming that the resultingpollution increases would violate this interstate pol-lution provision. Few of these legal suits, however,have been settled. While some uncertainty remainsover how the courts will interpret interstate pollu-

2Sec. 110 states that the SIP must contain: Adequate pro-visions (i) prohibiting any stationary source within the State from emit-ting any air pollution in amounts which will (a) prevent attainmentor maintenance by any other State of any such national primary orsecondary ~bient air quality standard, or (b) interfere with measuresrequired to be included in the applicable implementation plan for anyother State under Part C to prevent significant deterioration of airquality or to protect visibility and, (ii) insuring compliance with re-quirements of sec. 126, relating to interstate pollution abatement. (sec.1 l o ) .


tion control requirements, recent decisions suggestthat the Federal courts are not prepared to inter-pret section 110 to require broader con-sideration of interstate pollution effects than occursunder current EPA practices.

Section 126 allows any State or political subdivi-sion to petition the Administrator of EPA to remedyinterstate pollution. The language of section 126is relatively vague, and to date EPA has not issuedinterpretive regulations. The section relies on pro-visions of section 110 for determining theprohibited quantity of interstate pollution. A num-ber of States seeking relief from long-range inter-state pollution have filed section 126 petitions. EPAhas consolidated the petitions of the States of NewYork, Pennsylvania, and Maine into a single pro-ceeding. These States have requested far-reachingrelief from alleged interstate pollution problems,including revision of EPA policies and broad-scalereductions in emissions throughout the EasternUnited States.

EPA has not yet ruled on these petitions; despitethe statutorily mandated deadline (60 days) for rul-ing on a State’s petition, a number have been out-standing for years. States have the right to chal-lenge an EPA determination on a section 126petition in court, but no such challenge is possibleuntil EPA acts on the petitions. In March 1984,six Northeastern States sued EPA to rule on theoutstanding petitions but no court action has yetbeen taken.

Section 115 of the Clean Air Act provides an ad-ministrative mechanism for controlling pollutionthat crosses international boundaries. It is activatedeither by the Administrator of EPA or at the re-quest of the Secretary of State. If the Administratordetermines that the United States is causing or con-tributing to ‘‘air pollution which may reasonablybe anticipated to endanger public health or welfarein a foreign country, EPA must require revisionsto SIPS in the States in which the emissions origi-nate. Section 115 allows control of any air pollut-ant— unlike the interstate pollution provisions,which can be used only to control air concentra-tions of pollutants for which NAAQS have beenissued. Thus, the section may be interpreted to per-

mit direct control of acid deposition caused by trans-boundary pollution. *

Acid deposition resulting from long-range pol-lution transport has become a major issue betweenthe United States and Canada. At present, noagreement between the two nations directly ad-dresses transboundary air pollution; however, thetwo countries have begun negotiations to reach abilateral accord under a Memorandum of Intentsigned Aug. 5, 1980.

Options:

Specific options to clarify Clean Air Act provi-sions controlling long-range pollution transport(sections lo, 126, and 115) are describedbelow.

Option D-1: Amend the Interstate Pollution Pro-visions of the Clean Air Act.

Section 110 of the Clean Air Act is themajor existing interstate pollution provision. It wasdesigned to address local-scale interstate pollutionproblems. The section applies to air concentrationsof pollutants for which NAAQS exist (e. g., airborneparticulate); it does not directly address acid depo-sition. * *

Currently, EPA reviews only the effects of SIPrevisions on interstate pollution levels. States arealso concerned, however, with the cumulative emis-sions from sources outside their border leading topotential air quality degradation within their State.Several States have protested to both EPA and thecourts about EPA’s interpretation of this and otheraspects of the section.

● On Jan. 13, 1981, then EPA Administrator Douglas M. Costleannounced a finding of endangerment with respect to acid deposi-tion in Canada, and moved to activate this international provision.To date, however, EPA has sent no formal notification requiring revi-sion of any State implementation plan.

* ● Amendments to sec. 11 O(a)(2)(E). if combined with, for exam-ple, a new deposition standard, or ncw NAAQS for sulfates andnitrates, could in theory be used to control acid deposition. However,such mechanisms would offer, at best, an indirect and uncertain meansof doing so, They would leave to administrative discretion a wide rangeof political issues, including the size of the control region, the requiredamount of emission reductions, and the distribution of reductionsamong States or other regions. They would also require a lengthystandard-setting and allocation process, and could engender substan-tial legal and procedural battles among EPA, the States, and the Federalcourt system.

99-413 0 - 84 - 9 : QL. 3


Clarification of EPA’s responsibilities for restric-ting interstate pollution requires congressional guid-ance on several aspects of section 110.These include: 1) whether the section restricts in-terstate pollution from individual sources only, orfrom the cumulative emissions of sources through-out the State, 2) how much interstate pollution ispermissible, 3) what constitutes proof of causationof interstate pollution effects, 4) whether EPA isrequired to review the entire SIP for compliancewith section 11 O(a)(2)(E) when States revise a por-tion of their SIPS, and 5) whether EPA is requiredto review SIPS approved before the section wentinto effect.

Closely related to clarification of section 1 IO(a)(2)(E), Congress could require EPA to developguidelines for reviewing interstate pollution peti-tions (currently contained in section 126 of theClean Air Act). Section 126 could also be modifiedto require EPA to resolve petitions within a speci-fied amount of time. For example, Congress couldretain the 60-day requirement for holding hearingson a section 126 petition, but allow EPA additionaltime from the close of the hearing to reach a deter-mination. By further specifying de facto denial ofthe petition if the agency fails to make a determina-tion within, for example, 6 months to a year, Con-gress could make it possible for States to receivejudicial review of section 126 petitions in theabsence of administrative review by EPA.

Such changes could be effective in ending the cur-rent bottleneck of States’ petitions within EPA, per-mitting States to bypass stalled or inactive agencydecisionmaking procedures and move on to the ju-dicial-appeals process for section 126 petitions,

Option D-2: Amend the International Provisionsof the Clean Air Act.

Section 115 of the Clean Air Act was designedto address local pollution effects occurring near an

international border. However, an EPA adminis-trator who chooses to implement section 115 canrequire further control of any air pollutant fromany number of States that may contribute to an in-ternational pollution problem. The section providesno guidance on what levels or kinds of transbound-ary pollution are impermissible, how to allocatecontrol responsibilities among States, or how torevise SIPS to require control of pollutants for whichNAAQS do not exist. At present, the open-ended-ness of the authority delegated by section 115 makesit an unwieldy and potentially a politically volatiletool for controlling such long-range transported airpollutants as acid deposition and ozone.

The section could be amended to provide morespecific instructions and guidelines to the EPA Ad-ministrator. For example, Congress could direct theAdministrator to consult with the Department ofState to designate an appropriate internationalagency or establish a bilateral commission to deter-mine the magnitude of the problem and the levelsof control to be required. For addressing air pol-lution transport to and from Canada, Congressmight direct the Administrator to refer the prob-lem to the International Joint Commission, estab-lished by Canada and the United States in 1909to monitor transboundary pollution problems.

Activating section 115, however, could conflictwith other bilateral mechanisms for dealing withtransboundary pollution problems. In the case ofU.S.-Canadian acid deposition problems, initiatingaction under section 115 might interfere with ongo-ing talks with Canada under the 1980 Memoran-dum of Intent on Transboundary Air Pollution.

Chapter 7

Legislating Emissions Reductions

Contents

Page

Decision 1: Which Pollutants Should Be Further Controlled? . . . . . . . . . . . . . . . . . . . . . 123

Decision 2: How Widespread Should a Control Program Be? . . . . . . . . . . . . . . . . . . . . . 125

Decision 3: What Level of Pollution Control Should Be Required? . . . . . . . . . . . . . . . . 126

Decision 4: By What Time Should Reductions Be Required? . . . . . . . . . . . . . . . . . . . . . 130

Decision 5: What Approach to Control Should Be Adopted? . . . . . . . . . . . . . . . . . . . . . . 131

Decision 6: How Should Emissions Reductions Be Allocated? . . . . . . . . . . . . . . . . . . . . . 133

Decision 7: Who Should Pay the Costs of Emissions Reductions? . . . . . . . . . . . . . . . . . . 138

Decision 8: What Can Be Done To Mitigate Employment and Economic Effectsof a Control Policy? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140

TABLES

Table No. Page

6. Summary of Control-Policy Decisions and Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1237. Sulfur and Nitrogen Oxide Emissions by Region . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1268. Costs of Reducing Sulfur Dioxide Emissions in the Eastern 31 States . . . . . . . . . . . . . . . . 1299. Sulfur Dioxide Emissions Reductions With Emission Rate Limitations—

31 Eastern States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13510. Sulfur Dioxide Emissions Reductions With Emission Rate Limitations—

Entire United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13511. Emissions Reductions Required by Alternative Allocation Approaches . . . . . . . . . . . . . . . 13712. 50-State Taxes Raising $5 Billion per Year During the Early 1980’s . . . . . . . . . . . . . . . . 14013. Interstate Coal Shipments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142

Chapter 7

Legislating Emissions Reductions

Chapter 6 presented four approaches availableto Congress for addressing transported air pollut-ants. Under the first approach—further controllingthe sources of pollutant emissions—three optionswere discussed. These correspond to broad strat-

egies for further emissions control: mandating asmall-scale emissions reduction program; mandat-ing a large-scale program; and establishing a con-trol program based on an environmental qualitystandard.

If Congress decides to enact an emissions con-trol program at this time, the choice of one of thesethree broad strategies is only the first step in design-ing legislation. Policy makers would also have tomake a number of complex, interrelated decisionsto specify the details of the chosen strategy. For ex-ample, more than 10 bills before the 98th Congresspropose large-scale emissions reductions, but thedifferences among them are substantial.

Accordingly, this chapter is intended to serve asa guide for turning the broad emissions controlstrategies presented in chapter 6 into a legislativeproposal. It also provides a framework for evalu-ating specific provisions of the many acid deposi-tion control bills introduced to date. The chapterexpands on the brief discussion of the eight control-policy decisions presented in the previous chapter.Table 6 summarizes the eight decisions, along withtheir corresponding options.

Other transported air pollutants, such as ozoneand airborne sulfates, will be mentioned whereappropriate, but detailed options for controllingthem, either separately or in combination with aciddeposition, are not presented. Where possible, eachdiscussion will assess the current state of knowledge,the possibility of acquiring further relevant infor-mation in the near future, and the societal valuechoices involved.

Decision 1: Which Pollutants ShouldBe Further Controlled?

Discussion:

Most acid rain control proposals to date havefocused on reducing emissions of sulfur dioxide.There are several reasons for this.

Table 6.—Summary of Control-Policy Decisionsand Options

Decision 1: Which Pollutants Should Be Further Controlled?Option la: Sulfur Dioxide AloneOption lb: Both Oxides of Sulfur and NitrogenOption 1c: Sulfur Dioxide, Nitrogen Oxides, and

Hydrocarbons

Decision 2: How Widespread Should a Control Program Be?Option 2a: 21 Northeastern StatesOption 2b: 31 Eastern StatesOption 2c: 36 Eastern StatesOption 2d: 48 Contiguous StatesOption 2e: Allow EPA to Define Appropriate Control

Region

Decision 3: What Level of Pollution Control Should BeRequired?

Option 3a:Option 3b:

Option 3c:

Decision 4:Option 4a:Option 4b:Option 4c:

Option 4d:

Decision 5:Option 5a:

Option 5b:Option 5c:

Mandate Emissions ReductionsMandate Reductions, Including Offsets forFuture Emissions GrowthRequire EPA To Specify Reductions

By What T/me Should Reduction Be Required?6 to 10 years10 to 16 years, Allowing a Delay for Research8 to 12 Years, With a “Mid-Course”ReevaluationStagger Compliance Schedules

What Approach to Control Should Be Adopted?Directly Specify Emissions Reductions orEmission Rate LimitationsSpecify Use of Control TechnologiesEstablish an “Environmental Quality”Standard

Decision 6: How Should Emissions Raductions Be Allocated?Option 6a: Directly to SourcesOption 6b: To StatesOption 6c: Responsibility of Governors in Control

RegionOption 6d: Responsibility of EPAOption 6e: Allow Trading of Emissions Reductions

RequirementsOption 6f: Allow Substitution of Nitrogen Oxides

Emissions Reductions

Decision 7: Who Will Pay the Coats of Emissions Reductions?Option 7a: Sources Allocated Emissions ReductionsOption 7b: Establish a Trust Fund To Pay Part of Costs

Decision 8: What Can Be Done To Mitigate Employment andEconomic Effects of a Control Policy?

Option 8a: Require Reductions by Technological MeansOption 8b: Strengthen Clean Air Act, Section 125Option 8c: Establish Worker Assistance ProgramOption 8d: Utility Tax BreaksOption 8e: Pollution Control Technology R&DSOURCE: Off Ice of Technology Assessment.

Substantially greater amounts of sulfur dioxideare released into the atmosphere in the Eastern halfof the United States than nitrogen oxides. EasternU.S. sulfur dioxide emissions in 1980 were about

123.


22 million tons, whereas nitrogen oxides emissionswere about 14 to 15 million tons. Sulfur dioxideand its transformation products currently contributeabout twice as much to precipitation acidity in theNortheast as do nitrogen oxides.

Once deposited, sulfur compounds are more like-ly to threaten natural ecosystems than nitrogencompounds. While sulfur and nitrogen are both es-sential nutrients in soil ecosystems, most Easternforests require and retain far greater amounts ofnitrogen than of sulfur. Consequently, sulfur com-pounds are more likely to travel through watershedsand increase the acidity of water bodies, whilenitrogen compounds are more frequently taken upby plants before they reach lakes and streams. *Finally, approaches to controlling sulfur dioxide aremore developed than for nitrogen oxides.

Nitrogen oxides emissions, however, are ex-pected to contribute an increasing share to East-ern acid deposition, as nitrogen oxides emissionsare projected to rise at a faster rate than sulfur di-oxide emissions. In the Western United States, ni-trogen compounds currently contribute as much toprecipitation acidity as sulfur compounds do, andin many regions a greater amount. Nitrogen ox-ides are also involved in the production of ozone,a transported air pollutant known to damage cropsand forests.

Air concentrations of both nitrogen oxides andhydrocarbons influence the rate at which sulfur di-oxide is transformed to sulfates. Model-based stud-ies indicate that altering nitrogen oxides and hy-drocarbon concentrations does not affect total sulfurdeposition nearly as much as does directly reduc-ing sulfur dioxide concentrations. The presence ofthese “co-pollutants’ can alter wet sulfur deposi-tion, but does not significantly affect dry sulfurdeposition. The limited understanding of atmos-pheric chemistry, however, provides little guidancefor designing a control program involving thesepollutants along with sulfur dioxide. Appendix Cdiscusses how these other pollutants may potentiallyaffect the amount of sulfur deposited within theEastern United States.

● Nitrogen compounds deposited in snowfall are of greatest concernto aquatic ecosystems when they are released during spring snow melt.The “acid shock” caused by the acidity released from snow melt oc-curs during spawning periods, when fish populations are most sus-ceptible to damage.

Conclusions and Options:

Three pollutants are possible candidates for aciddeposition control: sulfur dioxide, nitrogen oxides,and hydrocarbons. Any program to control East-ern levels of acid deposition should include reduc-tions in sulfur dioxide emissions. Depending on thedesired degree of resource protection and geograph-ic extent and scheduling of the control program,other pollutants might be included as well.

Options available to the Congress are describedbelow.

Option la: Reduce Emissions of Sulfur Dioxide

Over the Eastern United States, deposition of sul-fur oxides is generally greater than deposition ofnitrogen oxides. In addition, sulfur oxides appearto have greater potential for damaging ecosystemsand degrading visibility, and are of concern becauseof possible health effects from airborne sulfates.While co-pollutants may affect the degree to whichcutting back sulfur dioxide reduces deposition, re-ducing sulfur dioxide emissions is the most plausi-ble means of reducing acid deposition in the East-ern United States.

Option lb: Reduce Emissions of Both Oxidesof Sulfur and Nitrogen

While cutting back sulfur dioxide emissions alonemay substantially reduce Eastern acid deposition,controlling nitrogen oxides emissions in additionto sulfur oxides would provide further protectionto sensitive natural resources. Currently, nitrogenoxides are the second greatest manmade source ofacidity. Nitrogen oxides emissions, however, haveincreased much more rapidly than sulfur dioxideemissions during the past few decades, and are pro-jected to increase an additional 25 percent by 2010.Thus, they will contribute an increasing share ofacid deposition. Reductions of nitrogen oxidesemissions would also help lower regional ozonelevels.

Congressional action to reduce acid depositionin the Western United States, if desired, must alsoaddress nitrogen oxides emissions. A nationwideacid deposition control program might therefore in-volve both pollutants.

Ch. 7—Legislating Emissions Reductions ● 125

Option 1c: Reduce Emissions of Sulfur Di-oxide, Nitrogen Oxides, and Hy-drocarbons

Sophisticated models of both the chemistry andmeteorology of the atmosphere may eventuallymake it possible to design more cost-effectivestrategies relying on control of all three pollutantsinvolved in acid deposition. The modeling capa-bility to design such a strategy for a near-term con-trol program, however, does not yet exist; and itis uncertain whether this capability will be avail-able within the next decade. Such multiple-pollut-ant control might best be considered for futurerefinements to an ongoing acid deposition controlprogram.

Decision 2: How Widespread Shoulda Control Program Be?

Discussion:

Most of Eastern North America—from south-ern Ontario and Quebec to northern Mississippi,Alabama, and Georgia, and from the AtlanticCoast as far west as the Mississippi River—receivesprecipitation more acidic than pH 4.5. This areaincludes large regions with lakes and streams con-sidered sensitive to the effects of acid deposition atthis level.

While a substantial fraction of pollutant emis-sions is deposited locally, the remainder travels withair masses moving over a region, and is depositedat distances and directions determined by prevail-ing chemical and meteorological conditions. Pol-lutants contributing to acid deposition may travelwell over 500 miles. A large share of sulfur depo-sition—in some regions, over half-originates fromsources over 300 miles away. For example, modelanalyses suggest that 50 to 70 percent of the sulfurdeposited in northern New York State, New Eng-land, and parts of southeastern Canada is emittedfrom sources more distant than 300 miles. * Con-sequently, acid deposition is regional in scope: emis-sions sources in a multi-State region contribute todeposition in many other regions, depending oncomplex and variable atmospheric conditions.

● These model-based analyses are discussed more thoroughly in ch.3 and app. C,

Many legislative proposals to date have focusedon a 31-State region encompassing the States eastof, and the first tier of States west of, the Missis-sippi River. Of the 26 to 27 million tons of sulfurdioxide emitted in the continental United States in1980, about 22 million tons, or 80 to 85 percent,came from this 31-State region. In addition, sulfurdioxide control proposals have focused on electricutilities, which emit about three-quarters of East-ern sulfur dioxide. In the West, utilities emit about30 percent, while industrial sources emit about 60percent (half of which comes from smelters). Theprevailing use of low-sulfur coal in the West resultsin significantly lower sulfur dioxide emissions rates.

Of the 21 to 22 million tons of nitrogen oxidesemitted in the continental United States in 1980,about two-thirds, or 14 million tons, came from the31-State region. In the East, about 35 percent camefrom utility combustion and about 15 percent fromnonutility combustion. In the West, utilities con-tribute about 20 percent and nonutility combus-tion about 30 percent of the total. Mobile sourcesemit about 45 percent of nitrogen oxides in bothregions.

As discussed in Decision 1, either sulfur oxides,nitrogen oxides, or some combination of the twocould be controlled uniformly across the chosen re-gion, or separately for subregions within it. Table

7 shows emissions data for the United States as awhole and for several regional breakdowns.


All of the legislative proposals to control aciddeposition to date have included emissions reduc-tions in, at least, the 21 Northeastern States. Wepresent four possible emissions control regions—all of which include this region, but extend southand west depending on the geographic extent of re-source protection desired. Congress could specifythe size of the control region directly in legislation,or require EPA to establish a control region thatbest meets congressional goals.

Congressional options are described below.

Option 2a: Require Emissions ReductionsFrom 21 Northeastern States

Given the geographic extent of sensitive resourcesexposed to high levels of acid deposition and the


Table 7.-Sulfur and Nitrogen Oxide Emissions by Region

S O2 emissions Percent of N Ox emissions Percent of(thousand tons) U.S. total (thousand tons) U.S. total

48 States. . . . . . . . . . . . . . 26,420 100 ”/0 21,120 100 ”/037 States. . . . . . . . . . . . . . 23,640 89 17,910 8531 States. . . . . . . . . . . . . . 21,810 83 14,000 6621 States. . . . . . . . . . . . . . 16,540 63 9,720 46Rockies, west. . . . . . . . . . 2,780 11 3,210 1517 Western States . . . . . . 4,620 17 7,120 34SOURCE: Costs. and Engineering Assessment, Work Group 3B, United States-Canada Memorandum of Intent on Transbound-

ary Air Pollution, June 15, 1982.

average distance of pollutant transport, we feel thesmallest effective control region would consist ofthe States east of the Mississippi River and northof (and including) Tennessee and North Carolina.This region roughly covers the portion of the UnitedStates receiving the most acidic precipitation—in1980 averaging lower than pH 4.5, a level thoughtto harm sensitive lakes and streams. About 65 per-cent of the Nation’s sulfur oxides and 45 percentof its nitrogen oxides are emitted in this region.

The region excludes, however, several majoremission-producing contiguous States—i. e., Mis-souri, the fifth largest sulfur dioxide-emitting State,and the southern States of Georgia, Alabama, andFlorida. Major nitrogen oxide-emitting States thatborder the region are Louisiana, Missouri, and theabove-mentioned Southern States.

Option 2b: Require Emissions ReductionsFrom 31 Eastern States

This region consists of those States east of andbordering on the Mississippi River, and has beenthe focus of most legislative proposals and controlstrategies to date. It emits about 80 to 85 percentof the Nation’s sulfur oxides and 65 percent of itsnitrogen oxides, One large emitter, Texas, bordersthis region, ranking sixth-highest in sulfur dioxideand first in nitrogen oxide emissions among the 50States. Texas utilities generally emit sulfur dioxideat relatively low rates, however, averaging 0.3 lbper million Btu fuel burned.

Option 2c: Require Emissions ReductionsFrom the 37 Eastern States

This region encompasses all States east of theMississippi, plus two tiers of Western States, i.e.,the States east of the Rocky Mountains. This re-gion emits about 90 percent of the Nation’s sulfur

oxides and 85 percent of its nitrogen oxides. Be-cause emissions rates in the six additional Statesare relatively low, applying most of the current acidrain control proposals to this region would not ap-preciably change reductions required from the 31Eastern States.

Option 2d: Require Emissions ReductionsFrom the Entire 48 ContiguousStates

This option treats acidic deposition as a nationalproblem and requires all regions to further controlemissions. While effects from acid deposition arecurrently of greatest concern in the East, highlyacidic precipitation events have been observed inparts of the Western States. As discussed previous-ly, different pollutants might be controlled in theEast (where sulfur dioxide is the major pollutant)and the West (where nitrogen oxide emissions aregreater).

Option 2e: Allow EPA To Define theAppropriate Control Region

Rather than legislating a specific control region,Congress could define the goals of a control pro-gram and require EPA to establish the control re-gion by a specified date. EPA could then use in-formation available at that time (e. g., pollutiontransport models, maps of sensitive regions, con-trol cost estimates) to demarcate a region consist-ent with congressional guidelines.

Decision 3: What Level of PollutionControl Should Be Required?

Discussion:

The decision on how much to reduce emissionsmust take into account two important components:

Ch. 7—Legislating Emissions Reductions . 127

1) the scientific question of the relationship betweenemissions reductions and resource protection, and2) the policy question of what is the sociallydesirable level of resource protection. The latter in-volves such policy concerns as balancing the costsof reductions with the expected resource-protectionbenefits, and distributing the risks and costs equi-tably among different groups and geographic areas.

No unique ‘ ‘formula” exists for comparing therisks of resource damage with the costs of furtheremissions controls. Neither scientific nor economicmethods can presently analyze the various policyconcerns precisely. Moreover, differing prioritiesamong regions and interest groups will lead eachto weigh these concerns differently. Several refer-ence points are available, however, for comparingboth the benefits and costs of various levels of re-duction.

Several groups1 have estimated maximum levelsof acid deposition that most sensitive lakes andstreams could receive without undergoing furtherdamage. Specifying deposition limits to protectagainst damage to such other resources as crops,forests, or materials is not yet possible.

OTA’s analysis of how emissions reductionswould affect deposition levels concludes that in areasof highest deposition—e. g., western Pennsylvaniaand northern West Virginia—reducing sulfur di-oxide emissions 8 to 10 million tons per year belowcurrent levels might not be sufficient to bring depo-sition levels within these recommended targets forprotecting all but the most sensitive aquaticresources. In areas of lower deposition, such asnorthern New England, the southern Appalachians,and the upper Midwest, the recommended deposi-tion limits might be achievable through sulfur di-oxide emissions cutbacks of this magnitude. Thus,reductions of this magnitude would probably notovershoot a possible congressional goal of protect-ing all but the most sensitive aquatic resources.

1 Work Group 1, Impact Assessment, U.S.-Canada Memorandumof Intent on Transboundary Air Pollution, Phase IZ Summary Re-port, October 1981; National Research Council, Acid Deposition,Atmospheric Processes in Eastern North America, Committee onAtmospheric Transport and Chemical Transformation in Acid Pre-cipitation (Washington, D. C.: National Academy Press, 1983); ~.S. Evans, et al., “Acidic Deposition: Considerations for an Air QualityStandard, ” Water, Air and Soil Pollution 16:469-509, 1981.

Risks of damage to sensitive forests, materials,and crops would also be reduced. In addition, air-borne fine-particulate levels would be lower, im-proving visibility and reducing risks to humanhealth.

Whether this is the desired level of protectionmust be addressed, however. Reducing emissionsby about 8 to 10 million tons of sulfur dioxide peryear below current levels (including offsets for ex-pected new growth) would cost about $3 to $6 bil-lion per year (1982 dollars), depending on the de-sign of the program. Smaller, less expensivecutbacks will provide less protection for sensitiveresources, but how much less is unknown. Largeremissions reductions might protect more resources,but the costs would rise steeply.

In addition to preventing potential future dam-ages, reductions might improve water quality incurrently acidified lakes and streams. Projectionsfrom a simple computer model have been used toestimate how reductions in sulfate deposition mightimprove water quality. * If sulfur dioxide emissionswere reduced to 8 to 10 million tons below 1980levels, about 15 to 40 percent of the aquatic re-sources already acidified or extremely sensitive tofurther acid deposition might experience somerecovery.

With emissions about 4 to 5 million tons below1980 levels, we estimate that water quality will im-prove in a maximum of 10 to 25 percent of theseaquatic resources. Reductions of this magnitude,including offsets for emissions growth, might beachievable for $1 to $3 billion per year (1982dollars).

Congress, however, might decide that the uncer-tain magnitude of benefits to be gained does notjustify such multibillion-dollar expenditures. Hold-ing emissions levels constant, or possibly decreas-ing them slightly below current levels, might be con-sidered more appropriate until more is known aboutthe extent of the risks to sensitive aquatic resources,forests, agriculture, materials, and human health.For expenditures of about $1 billion per year or less,about 2 to 5 million tons of sulfur dioxide can be

● This model assumes that the effects of acid deposition are not cumu-lative and are reversible in a short time period. If these conservativeassumptions are incorrect, the level of recovery will be slower.

128 ● Acid Rain and Transposed Air Pollutants: Implications for Public Policy

eliminated annually—certainly enough to offsetprojected emissions growth through 2000, and pos-sibly to decrease emissions levels 2 to 3 million tonsbelow 1980 levels by that time. This is likely to pro-vide some benefit to sensitive resources but, again,such benefits cannot be quantified accurately.

Given the uncertainty that reducing emissionswill decrease resource damage to the extent, andin the locations expected, and the resulting diffi-culty in estimating the benefits, policymakers mayhave to determine the level of emissions reductionsqualitatively. Even if both the benefits and costsof emissions reductions could be rigorously quan-tified--e.g., by the multiyear research program cur-rently under way in EPA and other agencies—sev-eral other factors would enter into the decision.

Many of the resources at risk from continued aciddeposition, such as lakes and forests, provide ben-efits that cannot be calculated solely in economicterms. While these resources do generate income—e.g., freshwater fishing and forestry are multibil-lion-dollar industries— they are valued for non-economic reasons as well. Similarly, losses inemployment in the high-sulfur coal industry fromemissions reductions may cause greater hardshipsthan estimates of lost income indicate.

Finally, benefits and costs of controlling trans-ported pollutants differ substantially among vari-ous economic sectors and geographic areas withina control region. Calculating aggregate benefits andcosts for the entire affected region ignores thesedistributional effects.


Congress could specify emissions reductions toreach a socially desired level of resource protection,considering the costs of further emissions control,the potential resource protection benefits, and otherpolicy concerns, The level of reduction chosen,however, must of necessity be a ‘‘best guess” basedon incomplete information.

For expenditures of $1 billion per year or less,enough sulfur dioxide emissions could be eliminatedto hold emissions constant (i. e., offset expected in-dustrial and utility growth), or to reduce emissionslevels 2 to 3 million tons below current levels bythe year 2000. This would reduce future risks to

sensitive aquatic resources, forests, agriculture, ma-terials, and health, but by how much is uncertain.Eliminating 8 to 10 million tons of sulfur dioxideannually from existing utilities by this date wouldcost $2 to $5 billion per year.

Reductions of this magnitude might protect allbut the most sensitive aquatic resources in manyareas, but might not afford this level of protectionin areas currently receiving the highest levels ofacidic deposition. The level of emissions reductionsnecessary to protect against potential damage tosuch other resources as crops, forests, or materialsis not yet known.

Once the aggregate regional level of emissionsreductions is chosen, Congress must further decidewhether the control program should be designedto accomplish: 1) a ‘ ‘one-time’ emissions reduc-tion (i. e., eliminating a specified emissions tonnagefrom existing sources, but not restricting futureemissions growth), or 2) an absolute ‘ ‘ceiling’ onregional emissions, thus requiring further reduc-tions as new sources are built.

An increase of about 1 to 3 million tons of sulfurdioxide emissions per year is projected by 1995. Thehighest rates of emissions growth are expected inthe South and the West. Thus, an absolute ceilingon emissions would be difficult to achieve in theseregions, as well as in those States that currently havelow emissions rates.

Alternatively, Congress could give EPA responsi-bility for setting reduction levels.

Options available to Congress are describedbelow.

Option 3a: Mandate Specific Levels ofEmissions Reductions

A congressionally mandated emissions controlprogram could range from preventing projected in-creases in emissions to large-scale reductions belowcurrent levels. In the Eastern 31-State region, apragmatic estimate of about 11 to 12.5 million tonsof sulfur dioxide per year constitutes the upper limitof feasible emissions reductions, given current tech-nology and costs. Larger reductions would requirestricter emission rate limitations for all existing util-ity plants than those currently applicable to newplants under New Source Performance Standards.


Table 8 presents estimates of the costs of con-trolling utility sulfur dioxide emissions in the East-ern 31 States. Cost estimates are for control strat-egies based on specified maximum allowableemission rates, assuming 1980 emissions and emis-sion rates. The costs of other programs will vary,depending on how emissions reductions are allo-cated and implemented. However, both the amountof sulfur dioxide emissions eliminated from existingfacilities and the extent of future emissions growthdetermine the net reductions at any future date.Future emissions growth in the region might shrinkthe reductions presented in table 8 by about 1 to3 million tons per year by 2000.

Option 3b: Mandate Reductions, IncludingOffsets for Future EmissionsGrowth

If Congress specifies emissions reductions, itmust also determine how to treat future growth inemissions. For example, added emissions from newsources would shrink an 8-million-ton cutback insulfur dioxide emissions from existing sources toan overall reduction of 5.5 to 6.5 million tons belowcurrent levels by 1995. This might be consideredadequate through about 2000, when the effective-ness of the program can be reevaluated.

However, to reduce overall emissions by, for ex-ample, 8 million tons below current levels by 1995,existing sources would have to reduce emissions by9.5 to 10.5 million tons. To offset emissions fromsources not yet built— already subject to tight con-trol under current New Source Performance Stand-ards—State plans would have to eliminate enough‘‘extra’ current emissions to accommodate poten-

tial future emission levels, or face the risk ofdiscouraging new industrial or utility growth.

For the more stringent emissions control pro-grams listed in table 8, offsetting future emissionsgrowth as well might cost an additional $1 to $2billion per year.

Option 3c: Require EPA To Specify EmissionsReductions To Meet CongressionalGoals

Congress could give EPA responsibility for set-ting reduction levels by a given date, according tospecified congressional goals for resource protec-tion and economic considerations. EPA could thenincorporate emerging research findings into its tech-nical judgment of what level of reductions are con-sistent with congressional goals. The choice couldbe left completely to EPA discretion, or be boundedby the Congress (e. g., eliminating 2-to-5 million,or 5-to-10 million tons of sulfur dioxide emissions).

Scientists might soon be able to estimate the ex-tent of aquatic resource protection afforded by vari-ous levels of emissions reductions, but might re-quire many years to develop similar estimates forother resources. Nonetheless, such estimates, evenfor aquatic resources, are likely to remain contro-versial for many years, due to uncertainties overhow reductions in emissions would affect deposi-tion levels, and how reductions in deposition levelswould affect aquatic resources. If Congress requiredEPA to weigh the benefits and costs of emissionsreductions, it would also need to specify the eco-nomic goals to be met, the kinds of benefits to beincluded in calculations, and the treatment of re-gional differences in costs and benefits.

Table 8.—Costs of Reducing Sulfur Dioxide Emissions in the Eastern 31 States(Excludes costs to offset future emissions growth; all costs in 1982 dollars)

Emission rate Emissions Average cost Marginal costlimitation reductions Total costa of reductions of reductions

(Ibs. SO2/million Btu) (million tons SO2) ($ billions) ($/ton) ($/ton)2.5 4.6 0,6-0.9 170-240 3202.0 6.2 1.1-1.5 200-280 4401.5 8.0 1.8-2.3 260-330 7001.2 9.3 2.6-3.4 310-400 740

10.3 3.2-4.1 350-440 8300.8 11.4 4.2-5.0 400-480 1,320

aExcludes costs to meet current SIPsbCost (in dollars per ton) to achieve the next increment of reductions.

SOURCE: Office of Technology Assessment, based on analyses by E. H. Pechan & Associates, Inc., 1983.


Decision 4: By What Time ShouldReductions Be Required?

Discussion:

This decision focuses on the tradeoff between therisk of resource damage from continued levels ofacid deposition, and the risk of inefficient or un-necessary control expenditures by acting on limitedknowledge of many of the atmospheric and ecolog-ical processes involved. Throughout the discussion,it is necessary to keep in mind that further emis-sions controls would take at a minimum about 6to 10 years to implement, given the planning, con-tracts, construction, and other steps necessary tosignificantly reduce pollutant emissions.

A “fast-track’ program—one requiring emis-sions reductions in 6 to 10 years—could probablybe met only if Congress directly specified theamount of reductions. Such a program would re-quire individual control decisions to be madequickly; even then, if large-scale reductions weremandated, it might not be possible to install scrub-bers and expand low-sulfur coal supplies rapidlyenough to meet the deadline.

Waiting 4 to 6 years for further research resultswould increase the time required to reduce depo-sition to 10 to 16 years, but might lead to a bettercontrol program. During the waiting period, knowl-edge of acid deposition and its effects will advance,and more cost-effective control technologies mightbe developed. However, it is not possible to counton significant scientific breakthroughs in this rela-tively short time.

An intermediate schedule could mandate reduc-tions now, but allow more time for implementa-tion than the ‘ ‘fast-track’ program. The programcould be designed to incorporate results from theFederal acid deposition research program in about3 to 5 years, to determine whether the control pro-gram should remain intact, be modified, or be dis-continued. Federal and State planning processescould proceed without delay—recognizing that theresearch program might not substantially alter cur-rent understanding-but such a program would notrequire additional pollution control expendituresuntil after the reevaluation point.

Innovative approaches to pollution control—e.g.,technologies such as LIMB (limestone injectionmultistage burners) or regenerable processes, dis-cussed in appendix A—raise additional scheduling-related issues, as they may take longer to plan andinstall than more traditional approaches. Congresscould provide incentives to try these potentiallymore cost-effective technologies by extending com-pliance deadlines when they are used.


A major emissions control program would re-quire, at minimum, about 6 to 10 years to imple-ment. A longer compliance period might be desiredto allow policy makers the opportunity to considerthe results of the Federal acid deposition researchplan. The additional delay, however, might resultin more extensive resource damage.

Options available to the Congress with regardto scheduling emissions reductions are describedbelow.

Option 4a: Require Reductions in 6 to 10Years

Achieving significant reductions within 6 to 10years would probably require Congress to specifyemissions reductions or emission rate limitations.State-level planning and source-level implementa-tion of reductions would have to proceed rapidly.Federal and private-sector acid precipitation re-search findings might occur too late to be used formodifying the program.

Option 4b: Require Reductions in 10 to 16Years, Allowing a Delay for Re-search

Delivery of Federal research results in 4 to 6 yearscould serve as the starting date for planning speci-fied reductions or an environmental quality stand-ard. Compliance with the program would then re-quire an additional 6 to 10 years.

Option 4c: Require Reductions in 8 to 12Years, With a “Mid-course’Reevaluation

Federal and State planning could begin immedi-ately, but the compliance date could be set so that


individual sources would not have to begin plan-ning construction and contracts until after a reeval-uation period in about 3 to 5 years. New researchresults, if any appeared, could be used to determinewhether the control program should remain intact,be modified, or be eliminated.

Option 4d: Stagger Compliance Schedules

To promote potentially more cost-effective tech-nologies, sources using innovative emissions con-trol approaches could be given extra time to com-ply with any of the schedules outlined in options4a through 4c.

If interim reductions are desired in conjunctionwith longer compliance schedules (e. g., options 4band 4c), earlier reductions could be required fromsources switching to low-sulfur fuels or from thosesources emitting at the highest rates. Mandatorycoal washing, though more expensive than ap-proaches that allow each source to choose its least-expensive alternative, is another method for achiev-ing interim reductions. This alternative has theadvantage of being potentially less disruptive to thecoal industry.

Decision 5: What Approach toControl Should Be Adopted?

Discussion:

Several regulatory frameworks are available tothe Congress for controlling transported air pollut-ants. These fall into two broad categories:

1. “Environmental quality” approaches—set-ting goals or standards for resource exposureto pollutants—including:● Establishing environmental quality goals or

standards based on air concentrations ofpollutants.

● Establishing environmental quality goals orstandards based on pollutant depositionrates.

2. “Source-based” approaches—directly regu-lating emissions from sources or regions—including:● Specifying total emissions reductions (in

tons of pollutants per year), or allowablepollutant emission rates (most commonlyexpressed as pounds of pollutant per unit

of fuel burned for stationary sources, andgrams of pollutant per mile for auto-mobiles).Requiring either specific types of controltechnologies (e. g., scrubbers), or tech-nology-based performance standards.

Air quality goals are currently implementedthrough both approaches. For example, NationalAmbient Air Quality Standards (NAAQS) are envi-ronmental quality standards, Allowable air concen-trations of pollutants are set to protect the publichealth and welfare. New Source PerformanceStandards (NSPS) are source-based standards.They seek to minimize future pollutant emissionsby regulating emission rates, even for cases in whichNAAQS would be met without their use. NSPS forcoal-fired utilities both set a maximum allowableemissions rate and require the removal of 70 to 90percent of potential sulfur dioxide emissions bytechnological means.

NAAQS might be used as a framework for con-trolling transported pollutants. Welfare-based sec-ondary standards for these pollutants could be mademore stringent and enforced more rigorously. Suchan approach might be effective for controlling re-source damage from ozone. To address acid depo-sition, Congress could require EPA to establishNAAQS for sulfate and nitrate particulate, theprincipal transformation products of sulfur dioxideand nitrogen oxides. To make the NAAQS ap-proach effective, EPA would have to broaden itsconsideration of long-range pollution transport.

The NAAQS are air concentration standards,however, designed to minimize human health ef-fects from breathing pollutants, crop and forestdamage from exposure to pollutant gases, or ma-terials damage from exposure to gases or particles.A different type of environmental quality stand-ard—a deposition standard-would be more con-sistent with our understanding of the environmentaleffects of acid deposition. Though conceptually at-tractive, a deposition standard would be quite dif-ficult to implement. Natural variations in precip-itation and wind patterns can cause an area’sdeposition to vary considerably from year to year.

Due to the many source regions and sensitive re-ceptor regions involved, designing measures tocomply with the standards, either at the Federalor State level, would be a difficult and time-con-


suming administrative and political process. More-over, while existing models can link large sourceregions to large receptor regions, identifying spe-cific sources responsible for deposition in specificareas far downwind is beyond their current capa-bilities.

A source-based approach—the one embodied inmost of the acid rain control proposals to date—would require emissions reductions throughout abroad region believed to contribute to acidificationin sensitive areas. Unlike deposition standards, theimplementation of source-based approaches is notrestricted by the major uncertainties and inherentcharacteristics of the acid deposition problem. Twotypes of source-based regulatory approaches arepossible: 1) directly specifying emissions reductionsor allowable emissions rates, and 2) limiting emis-sions by requiring the use of specific technologiesor technology-based performance standards.

The first approach can be used either to directlycontrol sources or to assign reductions to regions,leaving the choice of which sources to control toanother decisionmaking body. The advantages anddisadvantages of these alternatives are discussed inDecision 6: How Should Emissions Reductions BeAllocated?

Specified emissions or emissions rates give eachemitter the option of choosing the least expensivecontrol method, according to individual plant con-ditions. The second approach—technology-basedstandards—reduces or eliminates a plant’s options.Technology-based standards, however, avoid someof the adverse effects of ‘nontechnological’ meth-ods of pollution control—i. e., switching to cleanerfuels. Technological standards would minimize pro-duction and employment losses in many EasternU.S. coal regions. As discussed in detail in Deci-sion 8, there is a tradeoff between minimizing theseadverse, indirect effects of control, and allowingemitters to choose the least expensive controlmethod.


If Congress decides that an acid deposition con-trol program should be implemented in the nearfuture—within about 10 to 15 years-several‘‘source-based’ approaches to control are feasible.A control program based on an “environmental

quality” standard (similar to the ambient air qualitystandards of the Clean Air Act) might be possiblein the future, but the scientific tools needed to sup-port such an approach are not yet available.

Options available to Congress are discussedbelow.

Option 5a: Directly Specify Emissions Reduc-tions or Emissions Rate Limitations

Emissions limitations may be specified for eithera class of sources or by region. Decision 6 discussesthe distributional implications of various kinds ofreduction programs. The approach presumes thatthe effects of acid deposition are significant enoughto warrant emissions reductions, but that scientificuncertainties permit no more resolution in a con-trol approach than to reduce aggregate, regionalemissions. Limiting emissions by region or sourcecategory may involve inefficiencies in that it doesnot specifically seek to connect the location andamount of emissions to the location and sensitivityof areas of deposition. This approach, however, bestreflects current knowledge about the relationshipbetween emissions and acid deposition.

Option 5b: Specify the Use of Control Tech-nologies

Emissions could also be reduced by specifyingtechnology performance standards (e. g., 50-percentreduction, “best available, ” and so on) or mandat-ing the use of specific technologies (e. g., coal wash-ing). Like option 5a, the approach does not dependon linking source regions to receptor regions.

Technology-based standards are potentially moreexpensive than a control program that allows eachemitter to meet the required reductions through theleast-expensive (or otherwise advantageous) methodof control. Technology standards are adminis-tratively simple, however, and would minimize coalmarket disruptions that might result from other ap-proaches to control. (Potential effects on coal pro-duction are discussed in detail in Decision 8.)

Option 5c: Specify an “Environmental QualityStandard” Approach

Acid deposition control strategies could be pur-sued by: 1 ) establishing and enforcing more strin-gent secondary NAAQS for sulfur dioxide and ni-


trogen oxides, or 2) developing NAAQS for airconcentrations of sulfates and nitrates. SecondaryNAAQS for ozone are currently identical to thehealth-based primary standard—a l-hour maxi-mum allowable concentration. A secondary stand-ard based on a longer averaging time might betterreflect potential terrestrial resource damages fromchronic ozone exposure.

Alternatively, to control acid deposition, stand-ards could be developed to limit the rate of deposi-tion of acidity or sulfur and nitrogen compoundsover a given surface area, These standards couldvary regionally, depending on the sensitivity ofresources to acid deposition.

Because transported air pollutants routinely crossState boundaries, implementing an environmentalquality standard to control transported pollutantswould require Federal or regional mechanisms forrevising State Implementation Plans to meet thenew standards. This strategy is constrained by theproblem of linking well-defined source areas to well-defined receptor areas—a scientific question thatmay not be resolved for many years. Even if trans-port models were improved, the inherent variabilityof the atmosphere would require limiting the totalamount of pollutants emitted from a State or simi-lar-size region, rather than setting emissions limitsfor individual sources. Moreover, this approachwould involve a long and detailed standard-settingand implementation process. *

Decision 6: How Should EmissionsReductions Be Allocated?

Discussion:

Strategies for controlling transported air pol-lutants must address the following issues:

●

●

Who is to allocate emissions reductions tosources or States?If Congress chooses to allocate reductions di-rectly, what method should be used?

*For purposes of comparison, although Clean Air Act revisions in1977 directed EPA to review and revise the existing NAAQS for fivepollutants by 1980, as of 1983 only the standard for ozone had beenrevised. A revision had been proposed for carbon monoxide; the stand-ards review of the remaining three pollutants will probably be com-pleted by the end of 1984.

The question of who is to pay the control costs—amatter distinct from who is to reduce emissions—isdiscussed in Decision 7.

Two approaches are available to Congress for di-rectly specifying emissions reductions: 1 ) mandatinga reduction formula for all or a subset of individualsources within the region, or 2) allocating reduc-tions to States or other subregions, allowing anotherdecisionmaking group, such as a State or EPA, toallocate emissions reductions to individual sources.

Congress could also allocate emissions reductionsindirectly by assigning responsibility for designingallocation schemes, either with or without accom-panying guidelines. Congress might set a goal ofreducing deposition within a specified region, rec-

ognizing that a wide variety of allocation formulascould achieve that goal. Reductions from one sub-region could be substituted for those in a differentsubregion, within certain bounds, while still main-taining the same average pattern of deposition re-ductions.

Congress might provide additional guidelines—for example, that the eventual formula allocate re-ductions on the basis of the current best estimatesof how much sources contribute to deposition ingiven areas. Other guidelines might include mini-mizing costs to the control region as a whole, limit-ing the percentage of emissions to be eliminatedin any given region, or considering past pollutioncontrol efforts.

Four broad policy considerations are pertinentto designing an allocation formula for reducingemissions, or providing guidelines for others tofollow:

● Who is to gain the benefit of resource pro-tection,

● Who is to bear the burden of reductions,● The plan’s administrative efficiency, and● The plan’s economic efficiency.

In planning an allocation formula, tradeoffsamong these various interrelated concerns must beconsidered. For example, a plan that attempts tomaximize economic efficiency may be difficult toadminister, or might concentrate reductions in oneor more regions.

Political consideration of “Who is to gain thebenefit of resource protection” is intertwined with

134 ● Acid Rain and Transported Air pollutants: Implications for Public Policy

several of the issues discussed previously. Congresscould either attempt to reduce deposition in selectedhigh-deposition areas with large concentrations ofsensitive resources, or attempt broader-scale pro-tection. A uniform deposition standard, for exam-ple, implies the goal of protecting all areas equally,regardless of their concentrations of sensitive re-sources. Targeting specific areas for deposition re-ductions, however, favors one State’s resources overanother’s.

The decision on who reduces emissions must con-sider the scope of desired resource protection, aswell as other aspects of any allocation scheme. Aplan that provides uniform protection might dis-perse the required reductions over a larger area thanone focusing on sensitive regions. In addition, eachspecific formula affects the relative share allocatedto utilities as opposed to industries; regions whoselocal coals are higher or lower in sulfur content;and so on.

Allocating reductions on the basis of emissionsper area differs in costs and distributional impli-cations from a plan based on an allowable pollut-ant emission rate per amount of fuel burned. Thefirst approach concentrates reductions in areas witha high density of sources, even if these sources arerelatively pollution-free. The second approach fo-cuses on sources with high rates of pollution, eventhough the sources might be few and far between.Neither approach directly addresses such factors aspast emissions reductions or patterns of pollutiondeposition.

Appendix A presents eight alternative allocationformulas for reducing sulfur dioxide emissions, andthe implicit rationales and distributional conse-quences of each. Three are based on total emissions,five on utility emissions alone. Variants include for-mulas based on: emissions per area; emissions percapita; equal percentage reductions per State; State-average utility emissions rates; emissions above aspecified emissions rate; and emissions per quan-tity of electricity generated (including nonfossilenergy).

Another aspect of choosing an allocation formulais administrative feasibility. For example, manycontrol proposals have allocated emissions reduc-tions based on utility emissions not only becausethey emit about three-quarters of the sulfur dioxide

in the 31 Eastern States, but also because the re-maining emissions are difficult to characterize. Ac-curate estimates of emissions rates for many smallindustrial boilers are unavailable. Industrial proc-ess emissions would have to be regulated accordingto emissions per product, rather than per quantityof fuel burned, and separate standards would haveto be set for each industry.

Finally, for a given overall reduction, each alloca-tion formula results in a different distribution ofcosts, as well as different total costs. Controllingplants that emit at high rates is usually cheaper perton of pollutant removed than controlling loweremitting plants. However, the potential cost to theparticular source—or to the State with a large pro-portion of plants emitting at high rates—increasesas the required reductions increase. Allocation for-mulas that minimize total program costs tend toconcentrate reduction requirements on States withthe highest average emissions rates.


If Congress decides to directly assign emissionsreduction responsibilities to either sources or States,many reduction formulas are possible. Several poli-cy considerations pertinent to designing an alloca-tion formula include: 1) the resulting distributionof reductions (which determines both the distribu-tion of costs and deposition reductions; 2) the plan’stotal costs, and 3) the plan’s economic efficiency.Tradeoffs among these various interrelated con-cerns must be considered.

In addition to options for congressional alloca-tion of emissions reductions, we also present op-tions for: 1 ) assigning allocation responsibilities toeither EPA or the governors of States in the con-trol region, and 2) adding flexibility to the chosenformula by allowing trading of emissions reductionsrequirements.

Options available to Congress for allocating emis-sions reductions are described below.

Option 6a: Allocate Emissions ReductionsDirectly to Sources

Emissions reductions could be allocated directlyto sources by two means:

1. Legislating maximum allowable emissionsrates. Congress could set maximum allowable emis-


sions rates for electric utilities, industrial boilers,and industrial process emissions. Reductionsachievable by specifying alternative maximumemissions rates for utilities, industrial and commer-cial boilers, and all large boilers are presented forthe 3 l-State Eastern region in table 9 and for thecontiguous 48 States in table 10.

2. “Targeting” emissions reductions to specificsources. Reductions could also be allocated to onlythe largest sources. Of the 16 million tons of sulfurdioxide emitted by utilities in the 31-State Easternregion during 1980, close to 60 percent came fromthe top 50 sources, about 70 percent from the top75 sources, and close to 80 percent from the top

100 sources. Alternatively, Congress could targetthose plants emitting at the highest rates. About75 percent of 1980 utility sulfur dioxide emissionscame from plants emitting in excess of 2.5 lb ofsulfur dioxide per million Btu, and 60 percent camefrom plants emitting in excess of 3.0 lb of sulfurdioxide per million Btu.

These relatively few sources could substantiallyreduce regional emissions by using scrubbers underprocedures similar to the existing New Source Per-formance Standards. Each of these ‘‘targeted re-duction’ schemes, however, draws an arbitrarycutoff line—those just above it would be requiredto reduce emissions substantially (e. g., 90 percent

Table 9.—Sulfur Dioxide Emissions Reductions WithEmission Rate Limitations—31 Eastern States

Ibs. SO2/10 6 Btu . . . . . . . . . . . . . . . . . 1.0 1.2 1.5 2.0 2.5 3.0 4.0

All boilers (1980 emissions = 19,200 thousand tons/year)

Thousand tons/year. . . . . . . . . . . . . . 11,600 10,400 8,900 6,800 5,100 3,700 2,000Percent reduction in class. . . . . . . . 60 54 46 35 26 19 10Percent reduction below total a . . . . 53 48 41 31 23 17 9

Utility boilers (1980 emissions = 16,070 thousand tons/year)


Nonutility boilers (1980 emissions = 3,200 thousand tons/year)

Thousand tons/year. . . . . . . . . . . . . . 1,300 1,100 900 640 460 360 220Percent reduction in class. . . . . . . . 40 35 28 20 15 11 7Percent reduction below totala . . . . 6 5 4 3 2 2 1a1980 total sulfur dioxide emissions = 21,800 thousand tons/year.

SOURCE: E. H. Pechan & Associates, from Energy Information Administration data (EIA forms 4 and 423), and EPA NationalEmissions Data System (NEDS).

Table 10.—Sulfur Dioxide Emissions Reductions WithEmission Rate Limitations—Entire United States

Ibs. SO2/10 6 Btu . . . . . . . . . . . . . . . . . 1.0 1.2 1.5 2.0 2.5 3.0 4.0

All boilers (1980 emissions = 21,000 thousand tons/year)


Utility boilers (1980 emissions = 17,380 thousand tons/year)


Nonutility boilers (1980 emissions = 3,600 thousand tons/year)

Thousand tons/year, . . . . . . . . . . . . . 1,300. ,

1,100 930 660 480 370 230Percent reduction in class. . . . . . . . 37 32 26 18 13 10 6Percent reduction below totala . . . . 5 4 4 2 2 1 1a1980 total sulfur dioxide emissions = 26,400 thousand tons/year

SOURCE: E. H. Pechan & Associates, from Energy Information Administration data (EIA forms 4 and 423), and EPA NationalEmissions Data System (NEDS).

99-413 0 - 84 - 10 : QL. 3


reduction by technological means), while those justbelow the cutoff would be exempt.

Option 6b: Allocate Emissions Reductions toStates (or Other JurisdictionalEntities

Congress could allow States to achieve specifiedemissions reductions in any way they choose. Otherappropriate jurisdictional units include Air QualityControl Regions (AQCRs) or even operating util-ities (which often own several individual sources).

While this approach would add another layer ofadministrative complexity, allowing each State orother jurisdiction to allocate reductions offers po-tentially significant cost savings over uniformemissions rate requirements. For example, OTAestimates that for cutbacks of about 8 to 10 milliontons per year, allowing States to design “least-cost”allocation plans could reduce costs by about 20 to25 percent from those that impose uniform limitson emission rates.

Congress could allocate emissions reductions toStates in many ways. The allocation formula couldbe based on: 1) utility emissions alone (the sectorfor which the most accurate emissions data exist,2) emissions from both utility and nonutility com-bustion, or 3) total emissions (including industrialprocess emissions).

Reductions based on each State’s utility emis-sions or combined utility, industrial, and commer-cial boiler emissions could be calculated from:

. emissions in excess of a specified rate (sulfurdioxide emitted per quantity of fuel burned),or

. average emission rates (giving credit to Statesfor less polluting sources).

Reductions based on total emissions could be cal-culated from:

●

●

●

●

emissions per unit area,emissions per capita,equal percentage reductions for each State, ora series of allowable emission rates set sep-arately for each major sector (i. e., utilities,industrial boilers, and major industrialprocesses).

Other factors that could be incorporated intoState-level allocation formulas include:

● extent of use of nonfossil or low-emittingenergy sources, or

● upper limits on the extent of reductions re-

quired.

Table 11 compares the State-by-State emissionsreductions required under several of these alter-natives to achieve a total regional reduction of about8 million tons of sulfur dioxide per year.

Option 6c: Direct the Governors of the Statesin the Control Region To AllocateEmissions Reductions

Rather than assigning specific reductions toStates, Congress could require the governors of theStates within the control region to design an allocat-ion formula. Congress could either provide guide-lines or allow the governors complete freedom todevelop a plan. Congress would have to determinethe number of governors necessary to reach agree-ment (e. g., either a simple or a two-thirds majority)and alternative mechanisms in the event that agree-ment is not reached.

Option 6d: Provide Control Program Guide-lines and Direct the Administratorof EPA To Develop the AllocationFormula

This option must be used if Congress adopts anenvironmental quality standard approach, butcould also be used for developing an allocation for-mula following more general principles. For exam-ple, Congress could legislate resource protectiongoals (specifying equal protection from pollutantsfor all regions or greater protection in areas withhigh concentrations of sensitive resources), upperand lower limits on any State’s emissions reduc-tions requirements, guidelines for considering pastreductions, and so on. The Administrator of EPAwould then translate these goals as closely as possi-ble into regulatory language.

Option 6e: Allow Trading of Emissions Reduc-tions Requirements

To reduce the cost of implementing emissionsreductions, Congress could allow sources or States


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138 Acid Rain and Transported Air pollutants: Implications for Public Policy

to purchase reductions, rather than requiring eachsource or State to meet its own requirement direct-ly, This type of flexibility would allow sources withhigher-than-average control costs—due, for exam-ple, to engineering design or poor availability ofalternative fuels—to purchase the rights to morecost-effective reductions.

Congress could allow this type of tradingthroughout the entire control region, or permit itonly within smaller areas (e. g., EPA Federal re-gions) to maintain a desired regional pattern of re-ductions. Such trading could be allowed freely onthe open market, or through a marketable permitsystem to assist and monitor transactions.

If future emissions from sources not yet builtmust be offset by reductions from existing sources,allowing trading would be particularly helpful toStates with high rates of utility or industrial growth.

Option 6f: Allow Substitution of Nitrogen Ox-ides Emissions for Part of RequiredSulfur Dioxide Emissions Reduc-tions

For some sources, reducing nitrogen oxide emis-sions costs less than reducing sulfur dioxide emis-sions. To lower the costs of implementing requiredreductions, Congress could allow sources to choosethe mix of pollutant cutbacks that minimizes con-trol costs, subject to a specified substitution for-mula. Substitution of nitrogen oxides could be al-lowed on a ton-for-ton basis, 1.4 to 1 (the ratio ofthe acidifying potential of the two pollutants), orbe based on estimates of how the two pollutants af-fect natural ecosystems. Because much of the de-posited nitrogen is used by plants, substitutionratios ranging from 2 tons of nitrogen oxides foreach ton of sulfur dioxide, to ratios as high as 4to 1, might be considered.

Because the current inventory of nitrogen oxideemissions is not very accurate, however, a substitu-tion program based on historical emissions (e. g.,1980) would be difficult to administer. Given theuncertainties in nitrogen oxide emissions and incontrol cost data, OTA cannot estimate the extentof use or potential cost savings of such a provision.

Decision 7: Who Should Pay the Costsof Emissions Reductions?

Discussion:

Emissions control costs can be allocated accord-ing to two general approaches: 1 ) full costs of con-trol could be paid by sources required to reduceemissions, or 2) control costs could be funded froma group larger than those required. For example,a tax on pollutant emissions or electricity sales couldbe used to generate a trust fund to pay for re-ductions.

Currently, sources of emissions incur lower costsof production through their ability to dispose of pol-lutants in the atmosphere. These pollutants createcosts to people whose livelihoods depend on theresources at risk from acid deposition. The situa-tion, however, is not a simple case of ‘ ‘pollutingregion’ versus ‘‘receptor region. The benefits oflowered production costs are shared throughout theNation in the form of lower product prices, al-though the greatest benefit accrues in the locale ofthe source, Likewise, people living outside regionsthat have resources at risk benefit from using thoseresources, but the people within these regions bene-fit most.

The first approach allocates the control costs tothose who would be responsible for reductions. Yetsince it is not possible to precisely link emissionsfrom any given source to damage in areas far re-moved, some assert that this would be unfair.

The alternative approach would distribute thecosts of reductions to a larger group. For example,imposing a pollution tax implies that all emissionscontribute to the risk of resource damage, not justthose from sources emitting in excess of a speci-fied rate. Because so few sources are actually mon-itored, however, such an approach would be ad-ministratively complex.

Other trust fund approaches, such as a tax onelectricity generation, are also possible. Becauseelectricity generation is carefully monitored, thisapproach would be much easier to implement.Though an electricity tax approach is not based on


the amount of pollution produced, it recognizes thatenergy consumption creates much of the pollution.This approach, however, spreads the burden of con-trol costs to all energy consumers, even those inregions with lower polluting sources such as natu-ral gas or hydropower, and those already payingfor pollution control. Another alternative is an elec-tricity tax that is graduated on the basis of a pollu-tion emission rate, combining aspects of the twoprevious approaches.

A trust-fund approach has some undesirable eco-nomic and administrative aspects, though it is dif-ficult to estimate how severe these may be. A fundthat covered most or all of the costs of emissionscontrol could reduce incentives for sources to min-imize control costs. In addition, substantial plant-to-plant variations in scrubber costs and region-to-region variations in fuel-switching costs could createconsiderable difficulties in establishing allowablecost schedules.

OTA has compared the distributional implica-tions of three tax approaches: 1) a tax on electri-city generation; 2) a tax on sulfur dioxide emissions;and 3) a tax on both sulfur dioxide and nitrogenoxide emissions, set so that two-thirds of the reve-nues are generated from sulfur dioxide and one-third from nitrogen oxide emissions. This is roughlythe ratio of sulfur and nitrogen compounds depos-ited in precipitation in the Eastern United States.All three tax approaches are assumed to apply toall 50 States.

A tax on electricity generation would collect allrevenues from electricity consumers. A sulfur di-oxide tax would collect about 70 percent of revenuesfrom the utility sector, and about 30 percent fromindustry. Taxing both sulfur dioxide and nitrogenoxide emissions would collect 55 to 60 percent ofthe total revenues from utilities, 25 to 30 percentfrom industry, and 10 to 15 percent from highwayvehicles. Emissions from residential and other mis-cellaneous sources were not included in either ofthe pollution-tax approaches.

OTA analyzed how the alternative tax approacheswould affect costs for each State’s electricity con-sumers only. Since man y manufactured goods aredistributed nationwide, industrial costs are often

borne by consumers over a much larger area thanthe State in which the industry is located. A taxon highway vehicles (e. g., a sales or registrationtax) would be distributed on a roughly per-capitabasis.

Table 12 displays estimates of percentage in-creases in residential electricity rates from an elec-tricity tax raising $5 billion annually. State-to-Statevariations are due solely to differences in the aver-age electricity rate currently paid by consumers ineach State. Table 12 also shows residential electri-city rate increases under both pollution-tax alter-natives.

These approaches result in lower nationwide-average rate increases than an electricity tax be-cause part of the costs is borne by other sectors.Because of the large variation in pollution emissionrates among utility plants, however, costs wouldbe less evenly distributed, both within each Stateand from State to State. Because utilities emit alarger share of nationwide sulfur dioxide than ni-trogen oxide emissions, rate increases are typicallysomewhat lower for a tax on both sulfur dioxideand nitrogen oxide emissions (column 2) than onsulfur dioxide emissions alone (column 3).

Rate increases shown in table 12 illustrate therelative distribution of costs under 1980 conditions.Future changes in electricity demand and pollut-ant emissions could alter these estimates substan-tially. For example, reducing sulfur dioxide emis-sions by 10 million tons per year would reduce totalrevenues collected under a pollution tax by about15 to 30 percent, depending on the tax approach.Further details can be found in appendix A.


Under the Clean Air Act, sources that are re-quired to reduce pollutant emissions must pay theentire costs of control. Several acid deposition con-trol bills introduced to date would maintain thispolicy. Others have proposed a cost-sharing mech-anism, whereby a tax on electricity or pollutantemissions would be used to help fund the costs ofcontrol.

Options available to Congress are describedbelow.


Table 12.—5O-State Taxes Raising $5 Billion per YearDuring the Early 1980’s (total in later years will

vary with changes in emissions and electricity generated)

Average residential electricity rateincrease (percent) from alternate

tax approaches(Before control, 1980

Total emissions)State electricity SO2 and NOx SO2 onlyAlabama . . . . .Alaska . . . . . . .Arizona . . . . . .Arkansas . . . . .California . . . .Colorado . . . . .Connecticut . .Delaware. . . . .District of

Columbia . .Florida.. . . . . .Georgia . . . . . .Hawaii . . . . . . .Idaho . . . . . . . .Illinois . . . . . . .Indiana . . . . . .Iowa. . . . . . . . .Kansas . . . . . .Kentucky. . . . .Louisiana . . . .Maine. . . . . . . .Maryland . . . . .MassachusettsMichigan . . . . .Minnesota. . . .Mississippi . . .Missouri . . . . .Montana . . . . .Nebraska. . . . .Nevada . . . . . .NewHampshire . . .New Jersey. . .New Mexico . .New York . . . .North CarolinaNorth Dakota .Ohio. . . . . . . . .Oklahoma . . . .Oregon . . . . . .Pennsylvania .Rhode Island .South CarolinaSouth Dakota.Tennessee . . .Texas. . . . . . . .Utah . . . . . . . . .Vermont . . . . .Virginia . . . . . .Washington . .West Virginia .Wisconsin . . . .Wyoming. . . . .

4.04.03.14.43.03.72.52.4

4.53.14.21.88.23.63.8

3.74.54.23.33.62.94.33.84.04.16.44.73.9

2.92.62.92.13.74.13.34.5

3.13.03.63.64.93.73.63.53.39.54.24.46.1

2.00.90.70.60.21.30.31.4

2.21.7

0.80.02.95.93.01.85.70.50.41.81.62.51.8

6.60.91.31.0

2.90.81.00.71.81.94.50.60.12.71.31.41.15.30.70.80.11.20.54.14.13.0

2.51.40.70.50.21.20.31.8

2.72.24.51.10.03.67.73.52.0

0.20.62.32.13.02.02.68.80.91.30.9

3.6

0.90.92.12.05.90.30.13.51.51.71.17.00.50.60.0

0.75.15.22.9

1.9U.S. total . . . 3.3 2.3SOURCE: Off Ice of Technology Assessment.

Option 7a: Require the Sources AllocatedEmissions Reductions, and TheirCustomers, To Pay the Cost ofThose Reductions

This approach is simple to administer and pro-vides the greatest incentives for each source to min-imize control costs. Given the difficulty of preciselylinking emissions in one region with resource dam-age in another, however, many have questionedthe ‘ ‘fairness’ of the cost allocation.

Option 7b: Establish a Trust Fund To ProvideSome or All of the Necessary Fundsfor Reducing Emissions

Funds could be drawn from a tax on emissions,a tax on electricity production, or even from generalrevenues, This approach is administratively com-plex and might reduce incentives for minimizingcontrol costs. Costs would be distributed more uni-formly among States than under option A; still, thisdistribution of the costs and benefits of emissionsreductions also raises regional equity concerns.

Decision 8: What Can Be Done ToMitigate Employment and Economic

Effects of a Control Policy?

Discussion:

Two industries are likely to be most affected bylegislated reductions in sulfur dioxide emissions:coal mining and electric utilities, In the absence ofrestrictions imposed by Congress, emissions reduc-tions would be achieved through a mix of switchingto lower sulfur fuels and installing flue-gas desul-furization units (“scrubbers”). Individual sources’control decisions—unless specified by Congress—will be determined by the relative cost effectivenessof the two approaches for that source and location.

Both control options have undesirable conse-quences: fuel switching is projected to cause somecoal production to shift from high-sulfur to low-sulfur producing regions, affecting employment andeconomic patterns. Scrubbing allows the continueduse of high-sulfur coal, but imposes high capitalcosts on a utility industry already requiring addi-tional capital for continued growth and health.


As discussed in chapters 3 and 5, a program toreduce sulfur dioxide emissions by 10 million tonsper year might reduce mining employment in high-sulfur coal regions by 20,000 to 30,000 jobs fromotherwise projected future levels, and to cause eco-nomic activity in the range of $600 to $800 mil-lion per year to shift from high- to low-sulfur pro-ducing regions. These chapters also discuss theutility industry’s recent financial situation, show-ing that during 1980 utilities in a number of East-ern States were in relatively poor positions to raisenew capital either through bond-related borrowingor by issuing additional stock. An acid rain con-trol program could have some effect on the finan-cial health of these utilities, but the magnitude ofthe effect is unknown.

Two approaches are available to minimize theeffects of an acid rain control program on the coalindustry:

● The ‘‘technological approach, i.e, either di-rectly or indirectly mandating the use of con-trol technologies. For example, Congress couldrequire that a set percentage of the sulfur po-tentially emitted from coals be removed bytechnological means, regardless of how muchsulfur the coal contains.

● The ‘‘local coal approach, which would re-strict utility coal consumption on the basis ofthe location of the coal supply, as in Section125 of the Clean Air Act.

The technological approach could, in effect, re-quire sources to achieve reductions via high-remov-al emissions control technologies, such as wet ordry flue-gas “scrubbers. Such an approach is thebasis for current New Source Performance Stand-ards, which require 70- to W-percent removal ofpotential emissions by technological means. Be-cause the use of scrubbers cannot be avoided byswitching to lower-sulfur fuels, locally availablehigher sulfur coals—which tend to be cheaper be-cause of lower transportation costs—would oftenbe preferred.

Such a policy is not without additional costs,however. OTA analyzed the cost of installing scrub-bers on 50 of the largest utility plants emitting sulfurdioxide at a rate greater than 3 lb per million Btu.These 50 plants emitted about 7.6 million tons ofsulfur dioxide in 1980 and consume about 60 per-

cent of the high-sulfur coal produced for utilities.Mandating the use of scrubbers on these plantswould cost about $1.5 billion per year more thanallowing each plant to use the most cost-effectivemethod of achieving the same reductions.

In a control program eliminating 10 million tonsof sulfur dioxide emissions per year, such a provi-sion would increase total program costs by an ad-ditional one-third to one-half. Moreover, manyavailable technology-based emissions reductionmethods (e. g., wet scrubbing) produce large quan-tities of liquid or solid effluents. A typical 1,000MW plant scrubbing high-sulfur coal producesabout 200,000 tons of sludge per year. This mustbe disposed of—posing additional environmentalrisks— if useful products cannot be recoveredeconomically.

If more modest sulfur dioxide emissions reduc-tions are desired—less than 2.5 million tons peryear—Congress could require physical cleaning forall coal above a specified sulfur content. This tech-nology-based approach would also help prevent pro-duction and unemployment losses in high-sulfurcoal regions.

Additional coal-cleaning could eliminate mod-erate amounts of sulfur emissions at a relatively lowcost for existing boilers that use higher-sulfur coals.Costs range from about $250 to $350 per ton ofsulfur dioxide removed for Midwestern high-sulfurcoals to $1,000 to over $3,000 per ton removed forsouthern Appalachian low- and medium-sulfurcoals. The low range of coal-cleaning costs is com-petitive with or slightly higher than costs for fuel-switching.

Generally, the higher the sulfur content of thecoal, the more economical y the sulfur can be re-moved from it. Depending on the type of coal, 10to 40 percent of its sulfur can be fairly easilyremoved. If a greater percentage of the sulfur mustbe removed, physical coal washing alone becomeseconomically inefficient.

Coal washing is currently a widely used tech-nique. One-third of the utility coal mined in theEastern high-sulfur coal producing States waswashed in 1979, removing about 10 percent ofpotential sulfur dioxide emissions (about 1.8 mil-lion tons) from these coals.

—


In many instances, the benefits of coal cleaningcan partially offset the cost, because: 1 ) cleaningreduces the ash content of coal, reducing both costsof transportation to the powerplant and ash disposalrequirements at the powerplant; 2) removal of im-purities increases the heating value (energy per unitof weight) of coal; and 3) washing creates a moreuniform fuel that can increase boiler operation ef-ficiency.

The second major approach to mitigating thecoal-market effects of proposed emissions reductionsis based on section 125 of the Clean Air Act, whichallows the States or EPA to restrict coal consump-tion to coals produced ‘‘locally or regionally, ifsuch an action would ‘‘prevent or minimize sig-nificant local or regional economic disruption orunemployment. “ The potential effectiveness of thecurrent section 125 is difficult to judge becauseneither the statute, nor EPA in its ongoing proceed-ings, has defined “locally or regionally’ availablecoal or “significant’ economic disruption. No rul-ing has yet been made under section 125, althoughEPA has proposed a ruling based on a petition filedby the United Mine Workers and others in the Stateof Ohio in 1978.

Table 13.—lnterstate

Appropriately defining “locally or regionally”available coal is extremely important for design-ing a workable local-coal policy. If, for example,“local or regional” was to be considered synony-mous with State boundaries, invoking section 125would leave interstate trade in high-sulfur coalvulnerable to control-induced disruption. Table 13presents interstate exports of medium- and high-sulfur coal as a percentage of total utility coal pro-duction for each coal State. As much as 66 percentof Illinois’ and 82 percent of Kentucky’s high-sulfurcoal would remain vulnerable under such a defi-nition.

Protection can be increased only by expandingthe area considered local or regional, thereby in-corporating larger percentages of a State’s high-sulfur coal market. For example, if the Illinois ‘ ‘re-gion” were expanded to include Missouri, Indiana,and Michigan, the proportion of high-sulfur coalexported outside the ‘‘region’ would fall from 66percent (when considering only Illinois) to 21 per-cent (when considering all four States).

The variation in sulfur content of a “region’s’coal reserves is another factor that must be con-

Coal Shipments

Major 1980 production Noncompliance a coalcoal-producing for utility market exported to other States Major destination StatesStates (millions of tons) (percent of State production) (shipments greater than 1 million tons)

Alabama . . . . . . . . . . 15.8 10Arizona . . . . . . . . . . . 10.5 0Colorado. . . . . . . . . . 13.6 3Illinois. . . . . . . . . . . . 54.4 66 FL, GA, IN, 1A, MO, WIIndiana . . . . . . . . . . . 27.3 22 GA, KYKentucky . . . . . . . . . 112.4 73 AL, FL, GA, IN, Ml, MS, NC, OH, SC,

TN, VA, WV, WI(East). . . . . . . . . . . (73.9) (75)(West) . . . . . . . . . . (38.5) (69)

Missouri . . . . . . . . . . 5.0 34 KSMontana . . . . . . . . . . 27.9 52 MN, WINew Mexico. . . . . . . 17.0 1North Dakota . . . . . . 15.3 21 SDOhio . . . . . . . . . . . . . 34.3 27 AL, Ml, PAPennsylvania . . . . . . 50.9 30 MD, NY, OH, WITennessee . . . . . . . . 35Texas . . . . . . . . . . . . 27.0 oUtah . . . . . . . . . . . . . 8.5 7Virginia . . . . . . . . . . . 13.8 71West Virginia. . . . . . 53.1 MI, NJ, NC, OH, PA

(North). . . . . . . . . . (30.8) (46)(South) . . . . . . . . . (22.3) (30)

Wyoming . . . . . . . . . 89.7 10 IL, 1Aa“Noncompliance” coal is defined as coal that would not permit utilities to comply with a 1.2 lb SO2/million Btu emissions limit without applying control technology.

SOURCE: DOE/EIA Form 423, supplied to OTA by E. H. Pechan & Associates.


sidered when designing appropriate regionalboundaries. Including reserves of vastly differentsulfur content in the same region is unlikely to pre-vent disruption to the high-sulfur coal industry. Forinstance, defining a region to include southern WestVirginia and Ohio would still permit dramatic shiftsfrom high- to low-sulfur coal under the statutoryconstraints of section 125, since major quantitiesof low-sulfur reserves lie in southern West Virginia.

Thus, section 125 could effectively mitigate con-trol-induced coal-market shifts only if regions couldbe designed to include a significant portion of aState’s coal customers, while excluding large re-serves of coal with differing sulfur content. In prac-tice, a balance would have to be struck betweendefining regions large enough to protect sufficientamounts of coal, and small enough to exclude sig-nificantly different coal reserves.

The analysis above suggests that issues of defini-tion may present significant problems for effectiveimplementation of section 125. Moreover, restrict-ing competition among coal suppliers on the basisthat a given level of unemployment warrants Fed-eral action could cause a great deal of political con-troversy. EPA concludes that its ‘‘experience withSection 125 casts considerable doubt on the work-ability of this portion of the statute.

EPA suggested a third alternative, analogous toprograms providing adjustment assistance to work-ers, firms, and communities injured by foreigncompetition resulting from free-trade laws. A pro-gram could be designed to provide special compen-sation to workers and communities seriously af-fected by environmental regulations.

As of 1980, Congress had established about 20special worker-assistance laws that supplement reg-ular Federal-State unemployment insurance pro-grams. Most provide assistance to workers eitherunemployed or underemployed as a result of a Fed-eral action or policy. Several of these programs areongoing; for example, the Trade Act of 1974 pro-vides assistance to workers adversely affected byforeign competition. Others have been establishedto help workers so affected by one-time Federal ac-tions. These include temporary benefits for airlineemployees under the Airline Deregulation Act of

246 Fed. Reg. 8109.

1978, for loggers affected by the expansion of theRedwoods National Park, and for railroad employ-ees affected by the establishment of Amtrak andConrail.

The largest special worker-assistance program,the Trade Adjustment Assistance program to helpworkers hurt by foreign competition, paid $1.6 bil-lion to more than 500,000 workers during 1980.Most of the others are much smaller.

Benefits provided by these programs range fromrelocation, training, and job search benefits (butno direct monetary payments) to monetary benefitsranging from 60 to 100 percent of the worker’s sal-ary. Some programs are funded through congres-sional appropriations, while others receive fundsfrom the public or private corporations involved(e.g., the railroads absorbed by Amtrak). Most ofthe programs provide benefits for between 1 and6 years. Two programs provide benefits until age65.

To assist coal miners adversely affected by acidrain legislation, Congress could establish a specialworker-assistance program similar to those de-scribed above. The program could provide specialretraining to help workers find jobs in other indus-tries in their communities and assist workers thatdesire to move to other areas where greater employ-ment opportunities may be available. It should benoted, however, that during past fluctuations in coalproduction, workers in the Appalachian area havetended to remain in their home communities with-out jobs rather than relocate to areas where employ-ment opportunities may be greater.

Congress could also provide for direct paymentsto unemployed workers either for a set period (e. g.,1 to 6 years) or until retirement age. Funds for theprogram could come from congressional appropria-tions or through a trust fund established from a taxon electricity generation, pollution emissions, orcoal sulfur content.

Measures for reducing economic incentives toswitch to lower sulfur fuels, or for prohibiting theuse of nonlocal fuel, would increase scrubber-re-lated capital requirements for the utility industry.One method available to Congress to minimize thecapital burden on utilities, and the subsequent costto consumers, was discussed under the previous pol-icy question, ‘‘Who Should Pay the Cost of Emis-

144 ● Acid Rain and Transported Air Pollutants: implications for Public Policy

sions Reductions? A tax on electricity generationor pollution emissions could be used to reimburseutilities for all or part of the capital costs of pollu-tion control technology. Annual operating andmaintenance costs —about half the total costs ofcontrols— might still be paid by each utility’s con-sumers, but the burden of raising construction cap-ital would be reduced.

Modifications to the Federal tax code have beenproposed as another means of reducing the capitalcosts of pollution control. The Economic RecoveryTax Act of 1981 (Public Law 97-84) allows utilitiesto use accelerated depreciation to recover invest-ment costs. This provides tax benefits to utilities,creating more favorable cash-flow conditions.3 Theavailability of tax-exempt industrial developmentbonds to finance pollution control hardware (there-by allowing utilities to raise capital at lower interestrates) is another means by which the Federal Gov-ernment currently offsets the additional capital costsof pollution control.

Additional changes to the tax laws—e. g., increas-ing tax deductions for pollution control invest-ment —would help some, but not all, utilities to fi-nance pollution control technology. About 20percent of major privately owned utilities paid noFederal income tax in 1981. Over 50 percent paidsome tax, but took the maximum allowable invest-ment tax credit (85 percent of a company’s taxliability). 4

Another approach to reducing capital require-ments for pollution control is to encourage devel-opment of potentially lower cost control tech-nologies, such as LIMB (Limestone InjectionMultistage Burners) or regenerable processes. Atpresent, government and industry support for newpollution control technologies tends to emphasizetechnologies for sources yet unbuilt. Current lawdoes not require existing plants to use tech-nology-based pollution control for meeting ambientair quality standards.

Investments in research and development for pol-lution control technologies to retrofit existing

3For a discussion of how this law benefits utilties, see D. W. Kiefer,“The Impact of the Economic Recovery Tax Act of 1981 on the PublicUtility Industry, ” Congressional Research Service, 1982.

‘D. W. Kiefer, “Tax Credits: Their Efficacy in Helping the Util-ity Industry Finance Retrofitting to Reduce Sulfur Dioxide Emis-sions, Congressional Research Service, 1983.

sources are subject to both: 1) the risks inherentin any R&D program and, 2) the unpredictable de-mand for these technologies, given uncertaintiesabout future pollution control regulations. Federalcost-sharing of R&D for retrofitting existing sourceswould reduce investment risks and might encourageresearch on innovative, and potentially new, cost-saving technologies. The Federal Governmentcould also increase its own research activities in thisarea.

Conclusions and Options

In addition to the direct costs of control, aciddeposition control legislation could have undesirablesecondary consequences. Three options are pre-sented to minimize economic hardship to minersof high-sulfur coal. Two options are presented tohelp ease potential difficulties the utility industrymight face in raising capital to pay for pollutioncontrol technology.

Options available to Congress to mitigate unde-sirable effects of a control policy are describedbelow,

Option 8a: Require Sources To Reduce Emis-sions by Technological Means

Congress could mandate emissions reductions bytechnological means, to minimize potential produc-tion shifts within the U.S. coal industry and therebyminimize adverse regional employment and eco-nomic changes. For large-scale reductions, Con-gress could mandate control requirements similarto NSPS. Requiring emitters to remove a high per-centage of potential sulfur dioxide emissionsthrough such control technologies as scrubberswould minimize the economic advantage of switch-ing to lower sulfur coal.

For smaller reductions—up to about 2.5 milliontons of sulfur dioxide per year—Congress could di-rect EPA to require washing for particular coals.To minimize the costs of this option, Congresscould direct EPA to exempt those coals for whichwashing is not cost effective.

Mandating emissions reductions through tech-nological means would minimize unemploymentin high-sulfur coal areas and stimulate the pollu-tion control and construction industries. This ap-proach, however, would also increase overall con-


trol costs, limit the potential economic gains to areasthat produce low-sulk- coal, and increase electri-city costs to consumers.

Option 8b: Strengthen and Clarify the LocalCoal Protection Provision of theClean Air Act, Section 125

Section 125 of the Clean Air Act allows Statesor EPA to prohibit the use of coals that are not pro-duced “locally or regionally, ” if such an actionwould ‘ ‘prevent or minimize significant local or re-gional economic disruption or unemployment.Congress provided no guidance, however, on themeaning of these terms, and no ruling has beenmade under the section to allow policymakers todetermine its effectiveness.

Congress could enhance the section’s effective-ness by defining ‘ ‘significant” economic disruptionor unemployment (e. g., a threshold of projectedincreased unemployment of 10 percent, 20 percent,etc.). In addition, Congress could provide guidanceon defining a region for use in implementing thesection.

Assuming that the provision could be imple-mented effectively, it would achieve the same goalas option 8a—minimizing unemployment in high-sulfur coal regions—but would increase overall con-trol costs. EPA has stated, however, that its ‘ ‘ex-perience with Section 125 casts considerable doubton the workability of this portion of the statute.

Option 8c: Establish a Special Worker-Assistance Program for AffectedCoal Miners

Congress has established many special worker-assistance laws to help people that are either un-employed or underemployed as a result of a Fed-eral action. A similar program could be establishedto assist high-sulfur coal miners adversely affectedby acid rain legislation.

Such a program could provide direct monetarybenefits or relocation, training, and job-searchassistance, Funding for the program could comefrom either general tax revenues or a tax on elec-tricity, sulfur dioxide emissions, or coal sulfurcontent.

Option 8d: Reduce Utility Capital-Raising Re-quirements for Pollution ControlEquipment

Additional pollution control regulations wouldincrease the capital requirements of the utility in-dustry at a time when some utilities are in poor fi-nancial condition. Adopting either option 8a or 8bas part of an emissions reduction program wouldincrease the use of control technology, thereby in-creasing capital requirements even further.

Several means are available to Congress to aidutilities in raising the necessary capital. Twomeasures already in use are industrial developmentbonds to finance pollution control equipment andtax breaks under the Economic Recovery Tax Actof 1981 (Public Law 97-84). Ensuring the continuedavailability of low-cost industrial developmentbonds can lower the costs of pollution control equip-ment to both utilities and consumers. Additionaltax breaks, similar to the accelerated method ofdepreciation permitted by the Economic RecoveryTax Act of 1981, but specific to pollution controlequipment, could also be provided. Because manyutilities already pay little or no Federal income tax,however, such a policy would assist some, but notall, utilities that might choose technology-basedcontrols.

A more direct approach to reducing the capitalrequirements of the utility industry was presentedunder Decision 7. Congress could establish a taxon electricity or pollutant emissions to pay for allor part of the capital costs of pollution controlequipment.

Option 8e: Provide Federal Support for R&Don Pollution Control Technologiesfor Existing Sources

Congress could increase FederaI research and de-velopment activities or take measures to encourageprivate-sector R&D. More specifically, Congresscould establish a cost-sharing program for researchon innovative methods of retrofitting existingsources with pollution control technologies. Focus-ing the program on retrofit technologies would di-rect limited Federal funds to pollution controlmethods for sources most affected by possible acid

.


rain control legislation-existing sources that do not nologies that could reduce utility capital re-currently use pollution control technologies. A pro- quirements and minimize production shifts withingram to assume some or all of the risks of R&D the coal industry.might encourage development of cost-saving tech-

Appendixes

Appendix A

Emissions and the Costs of Control

A.1A.2

A.3

A.4

A.5A.6

HISTORICCONTROL

EMISSIONS OF SULFUR AND NITROGEN OXIDES (p. 149)TECHNOLOGIES FOR REDUCING SULFUR AND

NITROGEN OXIDE EMISSIONS (p. 153)ALLOCATION OF SULFUR DIOXIDE EMISSIONS REDUCTIONS ANDTHE COSTS OF CONTROL (p. 167)ALTERNATIVE TAX STRATEGIES TO HELP FUND ACID RAINCONTROL (p. 180)OTHER EMISSION SECTORS (p. 183)POTENTIAL SECONDARY ECONOMIC EFFECTS OF EMISSIONSCONTROL PROGRAMS (p. 190)

A.1 HISTORIC EMISSIONS OF SULFURAND NITROGEN OXIDES

During 1980, about 25 million to 27 million tons ofsulfur dioxide (S02) and about 21 million to 23 milliontons of nitrogen oxides (NOX) were emitted nationwideby electric utilities, industry, highway vehicles, andother sources. S02 emissions peaked around 1970 atabout 29 million to 31 million tons per year; NOX

emissions peaked during the late 1970’s at about 21 mil-lion to 24 million tons per year.

Estimates such as these are calculated from data col-lected by the Environmental Protection Agency (EPA)and the Department of Energy (DOE) on a large vari-ety of emitting sources. Pertinent information includes,for example, fossil fuel consumption, sulfur content offuels burned, and average NOX emissions rates fromvarious types of boilers and highway vehicles. Due tothe extensive data collection and monitoring activitiesof both agencies, current emissions estimates are accu-rate to within 5 to 10 percent nationwide. However, theuncertainty around emissions estimates is larger forprior years. Reasonably complete data exist for the lastthree decades; emissions between 1900 and 1950 mustbe inferred using whatever historical records exist.Assumed values are necessary to fill in missing data tocomplete the calculations.

Tables A-1 and A-2 present estimates of 1980 SO2

and NOX emissions by State and sector. These esti-mates were calculated by EPA for the U.S.-CanadaMemorandum of Intent on Transboundary Air Pollu-

tion. 1 Nonutility combustion (table A-1, co1. 3, tableA-2, co1. 4) includes emissions from industrial, commer-cial, and residential combustion sources. Industrialprocess emissions of SO2 (table A-1, co1. 4) include emis-sions from nonferrous smelters, petroleum refineries,cement plants, natural gas plants, iron and steel mills,and sulfuric acid plants. Transportation emissions ofNOX (table A-2, col. 2) include highway vehicles andsuch off-highway mobile sources as aircraft, railroads,vessels, and construction equipment.

Estimated historic emissions of SO2 and NOX from1900 to 1980 are presented graphically below.2 Theseestimates are from ongoing work by an EPA contrac-tor, and are subject to further review and revision. (Theestimates for 1980 agree to within about 5 percent withthe emissions estimates presented in tables A-1 and A-2. )

Figure A-1 presents State-level S 02 and NOX

emissions estimates for the period 1950 to 1980. Mostof the data needed to calculate these estimates wereavailable by State from various government reports;

]‘ Emlswms, Cnsts and Enq-meerln~ .%scssment, \$’ork Group 3B, Lrnlted.Statcs-Canadd ,Vfemor-andurn of [rrrt,rrr on Transbound~r;. Ar P(d/uri(In, ,J\Inc1982.

‘The maps and graphs presented In ~his xc tlon are from the clraf[ rep[,r t

‘‘ Hlstorl( F,mlssinns of Sulfur and Nltrogcn oxIdcs In the L’nltrxi Statt.. F’rc}rl]1900 [[l 1980, ‘ ‘ (; (;w hwan(ltner, K C ( A( hwandtner, a n d K El[irl(lqt, (At<)bcr 1983 ‘1’hc work was perfornlt.d t~} Pdc lfi( ~;n\ tronn~t, n[al Ser\,lc cs, I nc ,undc r ( orrt r.i( t [(] EPA

149


Table A-1 .—Estimated 1980 S02 Emissions (thousands of tons)

Total 1980 Utility Nonutility Process OtherState SO2 emissions combustion combustion emissions SO2 emissions

– L

Alabama. . . . . . . . . . . . . . . . .Alaska . . . . . . . . . . . . . . . . . .Arizona. . . . . . . . . . . . . . . . . .Arkansas . . . . . . . . . . . . . . . .California . . . . . . . . . . . . . . . .Colorado . . . . . . . . . . . . . . . .Connecticut. . . . . . . . . . . . . .Delaware . . . . . . . . . . . . . . . .District of Columbia . . . . . .Florida . . . . . . . . . . . . . . . . . .Georgia . . . . . . . . . . . . . . . . .Hawaii . . . . . . . . . . . . . . . . . .Idaho . . . . . . . . . . . . . . . . . . .Illinois . . . . . . . . . . . . . . . . . .Indiana . . . . . . . . . . . . . . . . . .Iowa . . . . . . . . . . . . . . . . . . . .Kansas . . . . . . . . . . . . . . . . . .Kentucky . . . . . . . . . . . . . . . .Louisiana . . . . . . . . . . . . . . . .Maine . . . . . . . . . . . . . . . . . . .Maryland . . . . . . . . . . . . . . . .Massachusetts . . . . . . . . . . .Michigan . . . . . . . . . . . . . . . .Minnesota . . . . . . . . . . . . . . .Mississippi . . . . . . . . . . . . . .Missouri . . . . . . . . . . . . . . . . .Montana . . . . . . . . . . . . . . . . .Nebraska . . . . . . . . . . . . . . . .Nevada . . . . . . . . . . . . . . . . . .New Hampshire . . . . . . . . . .New Jersey . . . . . . . . . . . . . .New Mexico . . . . . . . . . . . . .New York..... . . . . . . . . . . .North Carolina . . . . . . . . . . .North Dakota . . . . . . . . . . . . .Ohio . . . . . . . . . . . . . . . . . . . .Oklahoma . . . . . . . . . . . . . . .Oregon . . . . . . . . . . . . . . . . . .Pennsylvania . . . . . . . . . . . . .Rhode Island . . . . . . . . . . . . .South Carolina . . . . . . . . . . .South Dakota . . . . . . . . . . . .Tennessee . . . . . . . . . . . . . . .Texas . . . . . . . . . . . . . . . . . . .Utah . . . . . . . . . . . . . . . . . . . .Vermont . . . . . . . . . . . . . . . . .Virginia . . . . . . . . . . . . . . . . . .Washington . . . . . . . . . . . . . .West Virginia . . . . . . . . . . . .Wisconsin . . . . . . . . . . . . . . .Wyoming . . . . . . . . . . . . . . . .

U.S. total . . . . . . . . . . . . . .Percent of U.S. total . . . . . . 16 5SOURCE: Emissions, Costs and Engineering Assessment, Work Group 3B, United States-Canada Memorandum of lntent on Transboundary Air Pollution, June 1982.

75919

900102446132

72109

151,095

8405847

1,4712,008

329223

1,121304

95338344907260285

1,301164

75243

93279269944602107

2,64712160

2,02215

32639

1,0771,277

727

361272

1,088637184

54312882778773252

5726737

420

1,1261,540

231150

1,0082516

223275565177129

1,14123493480

11085

480435

862,172

383

1,4665

21329

934303

221

16469

944486118

8639

3256243526

89744

811

188290

57116676655658

15444485525

42

1075

2335116

13311

1525

2548

84

83106

165

1424184

10730

951

78729

197170

250

159146

30119151273929

1534

421

152187581

1045

2030

42166

7123

4118

528

2390

133

27719

270

1413243

529

352

1714

11613

562

11345

35

382713221850101711352232251117

52

52165928

546162463

2164

33148

61

41291640

826,557

10017,373

653,504

134,296 ‘1,385

App. A—Emissions and the Costs of Control ● 151

Table A-2.—Estimated 1980 NOX Emissions (thousands of tons)

Total 1980 Utility Non utility OtherState N OX emissions Transportation combustion combustion NOx emissions

Alabama. . . . . . . . . . . . . . . . .Alaska . . . . . . . . . . . . . . . . . .Arizona. . . . . . . . . . . . . . . . . .Arkansas . . . . . . . . . . . . . . . .California. . . . . . . . . . . . . . . .Colorado . . . . . . . . . . . . . . . .Connecticut . . . . . . . . . . . . .Delaware . . . . . . . . . . . . . . . .District of Columbia . . . . . .Florida . . . . . . . . . . . . . . . . . .Georgia . . . . . . . . . . . . . . . . .Hawaii . . . . . . . . . . . . . . . . . .Idaho . . . . . . . . . . . . . . . . . . .Illinois . . . . . . . . . . . . . . . . . .Indiana . . . . . . . . . . . . . . . . . .lowa . . . . . . . . . . . . . . . . . . . .Kansas . . . . . . . . . . . . . . . . . .Kentucky . . . . . . . . . . . . . . . .Louisiana . . . . . . . . . . . . . . . .Maine . . . . . . . . . . . . . . . . . . .Maryland . . . . . . . . . . . . . . . .Massachusetts . . . . . . . . . . .Michigan . . . . . . . . . . . . . . . .Minnesota . . . . . . . . . . . . . . .Mississippi . . . . . . . . . . . . . .Missouri. . . . . . . . . . . . . . . . .Montana . . . . . . . . . . . . . . . . .Nebraska . . . . . . . . . . . . . . . .Nevada . . . . . . . . . . . . . . . . . .New Hampshire . . . . . . . . . .New Jersey . . . . . . . . . . . . . .New Mexico . . . . . . . . . . . . .New York . . . . . . . . . . . . . . . .North Carolina . . . . . . . . . . .North Dakota . . . . . . . . . . . .Ohio . . . . . . . . . . . . . . . . . . . .Oklahoma . . . . . . . . . . . . . . .Oregon . . . . . . . . . . . . . . . . . .Pennsylvania. . . . . . . . . . . . .Rhode Island . . . . . . . . . . . . .South Carolina . . . . . . . . . . .South Dakota . . . . . . . . . . . .Tennessee. . . . . . . . . . . . . . .Texas . . . . . . . . . . . . . . . . . . .Utah . . . . . . . . . . . . . . . . . . . .Vermont . . . . . . . . . . . . . . . . .Virginia . . . . . . . . . . . . . . . . .Washington . . . . . . . . . . . . . .West Virginia . . . . . . . . . . . .Wisconsin . . . . . . . . . . . . . . .Wyoming . . . . . . . . . . . . . . . .

U.S. total . . . . . . . . . . . . . .Percent of U.S. total . . . . . .

45058

258217

1,225276134

5222

648494

4581

1,005773321437531928

592482546903732855681261958356

406290680536125

1,145526192

1,03736

26089

5172,544

14425

405289452420255

21,267100

16427

119131820115902214

347236

2652

42528016517618319042

143158302200125254

631243527

24697

385253

60438181144434

2812758

224745

6522

250193

8720869

9,36744

1720

9126

115862019

2214189

130

416361

9886

27298

16157

237112

50237

234043256680

130214

53516105

3390

384

200522

391

6225

302145103

83274045

2056723

96

5239

315

1299947

15167

552133737

1215379492222

44

681091395011

162216

25164

539

469

1,11333

26532555778

3149

1585

9121

3531

3153533

924

989

372

298

312718

811

254

2619

129242049

010

725

16370

2839

9116

6,22529

4,59522

1,0805

SOURCE. Emissions, Costs and Engineering Assessment, Work Group 3B, United States-Canada Memorandum of lntent on Transboundary Air Pollution, June 1982.

99-413 0 - 84 - 11 : QL. 3


Figure A.1.—SO2 and NOX Emissions From 1950 to 1980, By State

1950


when data were missing, information from the nearestyear of record was used.

During 1950, between 18 million and 21 million tonsof SO2 were emitted nationwide. By 1970, annual SO2

emissions had increased by about 10 million tons over1950 levels; between 1970 and 1980, emissions declinedby about 4 million tons per year.

Figure A-1 also illustrates the geographic pattern ofN OX emissions. During the 1950’s, nationwide NOX

emissions were about 8 million to 10 million tons peryear. By 1980, nationwide NOX emissions were overtwice 1950 levels.

Figure A-2 graphically illustrates SO2 and NOX

emissions from 1900 to 1980 by sector and geographic(multi-State) region. For SO2, the sectors include: elec-tric utilities; industry (including industrial boilersand—for 1950 and later—copper smelters and cementplants); commercial and residential boilers; and othersources, including railroads, vessels, and off-highwayvehicles. The sectors for which NOX emissions are esti-mated include those listed above, plus highway vehic-les and natural gas pipelines. The regions are single or

grouped EPA Federal regions, as shown on the accom-panying map.

Emission trends for SO2 show a consistent pattern ineach of the regions. While pre-1950 trends are uncer-tain, SO2 emissions appear to have increased until about1925, decreased during the Depression, increased onceagain during World War II, and then declined until the1950’s. After 1950, annual emissions increased throughabout 1970, and then declined. In some regions, for ex-ample, New York and New England (regions 1 and 2),this historic pattern of emissions increases and decreasesappears as variations around a fairly constant long-termaverage. In other regions, for example, the Mid-Atlanticand Southeastern regions (regions 3 and 4), short-termvariations accompany a longer term trend of increas-ing annual SO2 emissions.

Annual NOX emissions have increased throughoutthe century in ail regions. New York and New England(regions 1 and 2) show the lowest rates of increase, whilethe Southeast and South Central regions (regions 4 and6) show the most rapid increases.

A.2 CONTROL TECHNOLOGIES FOR REDUCINGSULFUR AND NITROGEN OXIDE EMISSIONS

Acid deposition and ozone result primarily from thechemical transformation of three pollutants: oxides ofsulfur, oxides of nitrogen, and hydrocarbons. This sec-tion discusses the techniques available for controllingemissions of oxides of sulfur and nitrogen. Where possi-ble, for each emission control approach, the followinginformation will be presented:

● the processes involved in the technique;. its stage of development, i.e. , whether the technol-

ogy is currently commercially available or requiresfurther research and development (R&D);

● the effectiveness of the technique, i.e. , the degreeof reduction it can reliably achieve;

c costs; and● secondary effects.The major source of nitrogen oxides and sulfur diox-

ide is the combustion of fossil fuels. During the com-bustion process, sulfur contained in the fuel reacts withoxygen to form sulfur oxides, primarily sulfur dioxidegas (SO2) and, after sulfate. Nitrogen—contained inboth the air used for combustion as well as in the fuel—reacts with oxygen to form gaseous nitrogen oxides(NOX). There are three general approaches to control-ling these emissions:

●

●

●

precombustion: the amount of sulfur or nitrogenin the fuel being burned can be reduced, either byusing fuels naturally lower in sulfur or nitrogencontent, or by subjecting the fuels to some kind ofphysical or chemical process to remove sulfur andnitrogen;during combustion: the combustion process canbe altered to reduce the amount of sulfur and ni-trogen compounds released in the gas stream; andpostcombustion: the products of combustion canbe treated to remove pollutants before they are re-leased into the atmosphere.

All three of these approaches have been successfullyused to reduce emissions from existing sources.

In addition to these differences among approaches tocontrol, the stage of development of the emissions con-trol techniques discussed in this appendix varies con-siderably. Technologies may be characterized as:

In-use technologies. —Those with demonstratedcontrol capabilities currently sold on a commercialscale in the United States.Available technologies.—Those that have beentested and proven but are not currently operationalin the United States on any significant scale.


0

o

C9

o “



0

ox

z

App. A—Emissions and the Costs of Control . 157

● Emerging technologies.--Those still primarily inthe R&D phase, but have undergone testing on atleast a pilot scale. *

Control approaches also differ widely in the amountof emissions reductions they are capable of achievingand in their cost effectiveness. Each technology is mostcost effective in a particular range of emissions reduc-tions. For instance, the precombustion approach ofphysical coal cleaning is technically feasible only for SO2reductions of less than 40 percent. On the other hand,the postcombustion approach of flue-gas desulfurizationis cost effective in the 50- to 95-percent SO2 removalrange. The control technique appropriate for a givenfacility thus depends a great deal on the level of reduc-tion desired.

Table A-3 presents summary information on the con-trol technologies described in this appendix. Due to site-specific conditions, the removal efficiency levels givenare intended for approximation only.

“’1’hl~ typolo$y IS used [u charactrrlm technnlw+cs In EmJ.ssIons, ~~osfs andEnK,necr,rrg .4sscwnent, W’ork Group ‘}B, J ( (Jn,[cd st~[~s.(;ana(la hiernoran-

dum of Intent on Trandmundarv .Alr Pollutmn, 1982 ‘‘

Table A-3.—Overview

Controlling Sulfur Dioxide Emissions

Precombustion Approaches

FUEL-SWITCHING

Sulfur dioxide is formed when sulfur, an element nat-urally present in coal and oil, is oxidized during thecombustion process. The greater the concentration ofsulfur in the fuel being burned, the greater the pro-duction of SO2 gas. One way to reduce SO2 emissionsis, therefore, to use fuels with lower concentrations ofsulfur.

The amount of emissions reductions attainable byfuel-switching at a given plant depends on: 1) theamount of sulfur in the fuel currently being used, and2) the amount of sulfur in the fuel available for replace-ment. The sulfur content of coal currently being usedfor electricity generation varies considerably, from about0.2 to 5.5 percent sulfur by weight (from about 0.4 to10 lb SO2 per million

of

3.5team Electric Plan? Factorstmn, 1978)

Control Technologies

Btu of coal).3

(W’ashinyton, [) (: National ( :(MI ASSIX Ia-

Reduction Revenueefficiencies Requirements Stage of

Control technology (percent) (mills/kWh) development

Sulfur dioxideFuel-switching. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-90 ”/0 o-7 In usePhysical coal cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-40 1-5 In useChemical coal cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60-85 NA EmergingWet flue gas desulfurization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70-95 10-17 In useDry flue gas desulfurization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40-90 9-15 In useRegenerable flue gas desulfurization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70-90 12-25 AvailableOil desulfurization:

Indirect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-40 4-6 In useDirect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70-90 NA In use

Nitrogen oxides:Low-NO X burner—commercial . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-50 0-3 In useLow-NO X burner—developmental . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50-80 0-3 EmergingThermal DeNox . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50-65 NA In useFlue gas treatment without catalyst . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35-40 NA AvailableFlue gas treatment with catalyst . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80-90 NA Available

Combined sulfur dioxide/nitrogen oxides:Limestone injection multistage burner:

Sulfur dioxide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50-90 3-5 EmergingNitrogen oxides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50-70 3-5 Emerging

Fluidized bed combustion:Sulfur dioxide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . <90 NA EmergingNitrogen oxides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-30 NA Emerging

SOURCE’ Office of Technology Assessment, primarily from EPA estimates.


The two principal components of the costs of fuel-switching are: 1 ) the “fuel-price differential, ” i.e., thedifference in price between the high- and low-sulfur fuel;and 2) the type of fuel-handling facilities, boilers, andemissions control devices at the plant. Low-sulfur coalis typically more expensive than high-sulfur coal, espe-cially in the East and Midwest.

Figures A-3 and A-4 illustrate the cost differences be-tween high- and low-sulfur coal. Figure A-3 shows thecosts of a high-sulfur, Illinois coal at various distancesaway from the mine. Similar costs are presented for anAppalachian low-sulfur coal in figure A-4. The costs ofthe low-sulfur coal are shown to be 50 percent higherthan the high-sulfur coal even in the areas closest to themines. The cost differential confronting specific utilityplants will vary considerably, depending on site-specificfactors and market arrangements.4

Many Western low-sulfur coals contain more ash thanEastern high-sulfur coals and can potentially emitgreater amounts of particulate. Therefore, particulateemissions control devices (electrostatic precipitators orbaghouses) generally have to be upgraded if low-sulfurfuels are used at existing plants. Fuel-handling facilitiesmay also have to be altered because Western coals areoften more difficult to pulverize than Eastern coals. Inaddition, certain kinds of boilers are designed to burncoal with very specific characteristics (e. g., energy yield,ash, and moisture content). These boilers would haveto be modified to burn low-sulfur coal efficiently orderated (i.e., produce less electricity). The capital costsof upgrading particulate controls, fuel-handling facil-ities, and boilers are relatively minor compared to theincreased fuel costs involved in fuel-switching. One esti-mate of the cost of achieving a 6-million-ton SO2 emis-sions reduction by fuel-switching at the 50 largestemitters is $1.4 billion per year (1982 dollars), or about$250 per ton of SO2 removed. ’

There are 217 billion tons of ‘compliance” coal (i. e.,capable of meeting an SO2 emissions rate limitation of1.2 pounds per million Btu (lb/MMBtu) without the ap-plication of control technologies) in the demonstratedreserve base. G This quantity of coal could support U.S.production for a period of about 50 years (assuming 50percent recoverability and 3 percent annual growth inconsumption). Therefore, achieving substantial emis-sions reductions through fuel-switching would not beconstrained by the resource base over the near future.

However, 85 percent of the Nation’s ‘‘compliance’reserves are located West of the Mississippi, while 63percent of coal consumption and 72 percent of coal pro-

‘E H, Pechan & Associates, information supplied to OTA, October 19815PEDC0 Environmental Inc , Acid Rain: Control Strategies for Coal-Fired

Utility Boilers—L’olume I, Summary Report, prepared for the Department ofEnergy, May 1981, tables 3-1 and 3-2.

CE. H Pechan & Associates, information supplied to OTA, April 1982.

duction occurs East of the Mississippi.7 In order to beviable, a large-scale emissions reduction program relyingprimarily on fuel-switching would have to significantlyexpand Western coal production and transportationcapacity. *

COAL CLEANING: PHYSICAL OR CHEMICAL

The second precombustion approach involves physi-cally or chemically treating coal to remove some of thesulfur it contains. Sulfur in coal exists in two majorforms: inorganic and organic. Inorganic or “pyritic”sulfur can be removed relatively inexpensively by ex-ploiting differences in the physical properties of pyriteand coal particles. Organic sulfur is chemically boundto the carbon molecules of coal, and can be removedonly by breaking the bonds through some chemical proc-ess. These chemical processes are less developed andmore expensive than the physical processes that removepyritic sulfur, but their sulfur removal potential ishigher. * *

Physical Coal Cleaning.—Physical coal cleaning(often called coal washing) takes advantage of differencesin the sizes, densities, and surface properties of pyriteand coal particles. The first step of the cleaning processis to separate raw coal into different size ranges. Break-ers and crushers are used to separate the softer coal fromthe harder rock and other debris contained in the coalentering the treatment plant. After breaking and crush-ing, the coal is typically filtered through screens to divideit into coarse, intermediate, and fine size ranges.

The method used to extract the pyritic sulfur fromthe coal depends on the size of particles. Coarse and in-termediate size particles allow differences in the specificgravity of pyritic sulfur and coal particles to be used (py-rite has a specific gravity of 5—i. e., is five times heavierthan water; coal is approximately 1.4). The coal mixtureis immersed in a fluid, where the heavier pyritic particlessink and the lighter particles float. The coal product andrefuse material can then be removed separately.

Fine mineral particles cannot be effectively separatedby the specific gravity techniques. Physical coal cleaning

‘U.S. Department of Energy, Energy Information Administration, Coal t%-cfucrion-1979, DOE/EIA-01 18(79), Apr. 30, 1981

*See Ollice of Technology Assessment, Direct Use of Coal, OTA-E-86, April1979, O’I-A, An Assessment of Development and Production Potential of Fed-eral Coal Leases, OTA-M- 150, December 1981, especially ch. 12. For an ac -cuunt of the socioeconomic’ effects of the decline of coal production, see T. RFord (cd,), The Southern Appalacluan Region, A Sur\,ey (1.exmgton, Ky.University of Kentucky Press, 1960)

● “FoI a survey of coal-cleaning techmques, see James D. Kilgroe, “CoalCleaning for Sulfur Cioxide Emission Control, ” paper submitted to the AcidRain Conference, Springfield, Va , Apr 8-9, 1980 The description of physi-cal coal cleanutg in this section relles heawly on Kdgroe’s paper Otber surveysof coal-cleaning techniques can be found m EPA-450/3-81 -004, Control Tech-niques fix Sulfur Oxicfe Emissions Fmm Stationary Sources, 2d ed , Aprd 1981,and F, PA-600/7-78-002, Engineering/Economic Analyses of Cod Prepara[iunWith S02 Cleanup Processes, January 1978,


7

x

Ez



of fine particles relies on a process in which the raw coalparticles are treated with a chemical that, because ofdifferences in surface properties, adsorbs differently onthe surface of coal particles than other substances in themixture. Air bubbles introduced into the chamber attachto the coal particles and carry the coal to the surface,where they can be skimmed off. The pyrite and otherparticles sink, and are removed separately.

Table A-4 shows the extent to which coal producedfor the utility market by eight Eastern and Midwesterncoal-producing States is physically cleaned. One-thirdof the coal produced by these States for utility waswashed in 1979, resulting in an estimated 1.8-million-ton reduction in the potential SO2 emissions (approx-imately equivalent to a 10-percent reduction in the po-tential SO2 emissions). 8

The emissions reduction potential of physical coalcleaning depends primarily on: 1 ) the initial sulfur levelin the raw coal, 2) the ratio of pyritic to organic sulfur,and 3) the coal-cleaning technique used. Pyritic sulfuraccounts for between 30 and 70 percent of the total sulfurcontent of Coal. g Higher sulfur coals tend to have a largerproportion of pyritic sulfur than lower sulfur coals. Con-sequently, the higher the sulfur content of coal, thegreater the percentage removal possible through thisprocess. Table A-5 shows the results of an analysis pre-pared for the Environmental Protection Agency (EPA)on the potential for sulfur removal by coal cleaning ineight Eastern and Midwestern States. 10 As the first

‘\’ersar, Inc , Coal Rrwources and Sulfir Err]l.won Rt-gularlorrs .4 Sur\c~of El,qht Eastern and .\ fdwestern Srares, prepared for EP.4, PM 1-240319, May1981

‘Jamm D Kllgroe, ‘ ‘Coal (;leaning for Sulfur Dloxlcic Emission Control,pap-r suhmltted to the Acid Ram Conference, Sprm#ielci, \’a , Apr 8-9, 1980

1“\rersdr, op c It

column of the table shows, reductions of between 8 and33 percent are attainable. The second column lists theSO2 emissions rate (in lb/MMBtu) achievable after coalwashing.

Table A-6 shows the costs and emissions reductionpotential of requiring all coal to be cleaned before itsuse. An additional reduction in SO2 emissions of about2.5 million tons could be achieved from the coals pro-duced by these eight States (equivalent to a 17-percentreduction of emissions from coal produced by theseStates). As the table shows, coal cleaning is associatedwith a wide range of costs—from a low of $224/ton ofSO2 removed in Indiana to a high of over $3,000/tonremoved in southern West Virginia (in 1982 dollars).Cleaning high-sulfur coals-those with the largest emis-sions reduction potential—is in general more cost ef-fective than cleaning lower sulfur coals. The regionwideaverage cost (not including southern West Virginia andVirginia) is about $505/ton of SO2 removed. Coal clean-ing adds between $4 and $9/ton to the price of coal, andbetween 2 and 4 mills/kWh in annual revenue require-ments. 11 This compares with an average price of resi-dential electricity of about 50 to 60 mills/kWh. 12

A Department of Energy contractor has assessed thecosts and emissions reduction potential of washing thecoal delivered to the 50 largest emitters in the UnitedStates. SO2 removal efficiencies range from 3 to 34 per-cent. Costs range from $4 to $7/ton of coal cleaned, $170to $4,900/ton of SO2 removed, and from 0.8 to 4.4 mills/kWh (1980 dollars). Cleaning the coal used by these 50

11 Ibid“U. S Department of Energy, Energy Information Admmlstratmn, 1980 An-

nual Report to Con,gre.ss, i’olume 11, DOE/EIA-01 73-80/2.

Table A-4.—Reductions in 1979 SO2 Emissions Achieved by Cleaning Utility Coal From Eight States

Sulfur content of coal Average SO2

Coal delivered Utility coal (expressed as 101 tons SO2) reduction byto utilities cleaned in delivered coal cleaning

in 1979 1979 As mined in 1979Region and State in which coal was mined (103 tons) (percent) (10s tons) (10 s tons) (percent)

Northern Appalachia:Pennsylvania. . . . . . . . . . . . . . . . . . . . . . . 47,400 30 2,100 1,860 12Ohio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38,300 11 2,750 2,670 3Northern West Virginia . . . . . . . . . . . . . . 31,300 23 1,760 1,690 4

Southern Appalachia:Southern West Virginia. . . . . . . . . . . . . . 17,500 9 300 290 1Virginia . . . . . . . . . . . . . . . . . . . . . . . . . . . 13,400 7 280 270 1Eastern Kentucky. . . . . . . . . . . . . . . . . . . 68,600 22 1,630 1,570 4

Eastern Midwest:Western Kentucky . . . . . . . . . . . . . . . . . . 38,100 34 2,880 2,600 13Indiana. , . . . ... , , ... , ... , ., . . . . . . ., 25,300 52 1,620 1,410 13Illinois . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49,500 72 3,570 2,780 22

Alabama:Alabama. . . . . . . . . . . . . . . . . . . . . . . . . . . 14,600 32 460 440 5

Eight-State total/average. . . . . . . . . . . 344,000 33 17,350 15,580 10SOURCE: Versar, Inc., Coal Resources and Sulfur Emission Regulations: A Survey of Eight Eastern and Midwestern States, prepared for EPA, PB 81-240319, May 1981.


Table A-5.—Average SO2 Emission Reductions and Emission Rate Potentials forCoal From Eight States (1979 data)

Average emissionreduction using Average Number of

physically cleaned coala emission potential washabilityRegion and State (percent) (lb SO,/MMBtu) samples -

Northern AppalachiaPennsylvania . . . . . . . . . . . . . . 33.2 4.0 170Ohio . . . . . . . . . . . . . . . . . . . . . . 25.9 5.8 90Northern West Virginia. . . . . . 28.9 4.9 30

Southern Appalachia:Southern West Virginia . . . . . 10.1 1.4 16Virginia . . . . . . . . . . . . . . . . . . . 7.6 1.1 8Eastern Kentucky . . . . . . . . . . 15.9 2.3 13

Eastern Midwest:Western Kentucky . . . . . . . . . . 31.5 6.6 37Indiana. . . . . . . . . . . . . . . . . . . . 26.4 5.9 21Illinois . . . . . . . . . . . . . . . . . . . . 29.3 6.6 40

Alabama . . . . . . . . . . . . . . . . . . . . 10.8 2.0 10%Coal crushed to 1/12 inch top size and separated at 1.6 specific gravity.SOURCE: Versar, Inc., Coal Resources and Sulfur Regulations: A Survey of Eight Eastern and Midwestern States, prepared

for EPA, PB 81-240319, May 1981.

Table A.6.—Typical Cost Effectiveness of Additional Coal Cleaning for Eight Eastern and Midwestern States

Additional annual Levelized cost Cost effectivenessSO2 reduction of cleaning (1982 $/ton SO2 removed)

Region and State 1 03 ton Percent (1982 $/clean ton) Without benefits With benefits

Northern Appalachia:Pennsylvania . . . . . . . . . . . . . . . . . . . . . 450 24 $6.90 $476 $301Ohio . . . . . . . . . . . . . . . . . . . . . . . . . . . . 720 27 8.36 369 233Northern West Virginia . . . . . . . . . . . . 250 15 6.70 564 398

Eastern Midwest:Western Kentucky . . . . . . . . . . . . . . . . 530 20 5.44 243 101Indiana . . . . . . . . . . . . . . . . . . . . . . . . . . 170 12 3.79 224 49Illinois . . . . . . . . . . . . . . . . . . . . . . . . . . 210 5 5.64 330 155

Southern Appalachia:Southern West Virginia . . . . . . . . . . . . — O 6.70Virginia. . . . . . . . . . . . . . . . . . . . . . , . . . — O

c c7,09

Eastern Kentucky . . . . . . . . . . . . . . . . . 150 8.45 991 680Alabama . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 5 1 5 6.51 845 437

Eight-State total/averaged . . . . . . . . . . 2,545 16 6.56 505 294

aOver current practice.bOf raw coal.cThese coals typically have a cost effectiveness exceeding $3,000/tondAverages do not include States where insufficient data are given.

SOURCE: U.S. Environmental Protection Agency, draft memorandum, Coal Cleaning Background Paper, May 19, 1963. (Note: this memo has not been formally releasedby the U.S. Environmental Protection Agency and should not be construed to represent Agency policy.)

plants is estimated to yield a 1.5-million-ton reductionin S02 emissions (about 7 percent of total SO2 emissionsin the Eastern United States) at an average annual costof $870 million, or $580/ton of SO2 removed. 13 Thisstudy does not account for the emissions reductions orcosts of coal used by these utilities that is currently beingcleaned.

Coal cleaning has several benefits in addition to re-duced SO2 emissions. First, cleaning reduces the ashcontent of coal, reducing ash disposal requirements at

I JpE~~O, Op cit. , May 1981

the power facility. Second, the removal of impurities(sulfur, ash, and others) increases the “heating value”(energy per unit of weight) of coal, Increased heatingvalue reduces coal transportation costs and pulverizationrequirements at the plant. Finally, because cleaningcreates a fuel with more uniform characteristics (e. g.;ash, moisture, sulfur, and energy content), increasedefficiency of boiler operation is possible. 14 These benefits

1~Eng,~eeri~g/&Ono~iC An~yS~ of Coal Preparation with SOZ cleanup

Processes, U S. Environmental Protection Agency, EPA-600/7 -78-O02, January1978; see also, Cost Benefits Associated With the Use of Physically CleanedCoaJ, prepared by PEDCO, EPA-600/7-80-105, May 1981,

.


can in many instances offset a large portion of the costsof coal cleaning.

Physical coal cleaning may produce a substantialamount of solid waste. The cleaning process causes ap-proximately one-fourth of the mined material to bediscarded as waste. 15 Moreover, some coal (approxi-

mately 5 to 10 percent of the energy value) is lost inthe process of removing impurities. 16

Chemical Coal Cleaning.—Chemical coal cleaningcan remove higher percentages of sulfur contained incoal because it can in some cases remove organic as wellas pyritic sulfur. These processes, however, have onlybeen successfully operated at the laboratory scale, andare estimated to be 5 to 10 years away from commercialviability. Chemical coal-cleaning processes vary widelyfrom relatively simple methods that use chemical solu-tions to leach sulfur and other impurities out of coal,to processes such as solvent-refined coal, which altersthe characteristics of coal so much that it is usually con-sidered a coal-conversion process. 17

Two of the chemical coal-cleaning processes receivingthe greatest amounts of current research attention arethe Meyers process and microwave desuIfurization. TheMeyers process, developed by TRW, Inc., is a chemi-cal leaching process that combines coal with a ferricsulfate or sulfuric acid solution to remove sulfur. Thisprocess can remove 80 to 99 percent of the pyritic sulfurin coal (larger removal efficiencies than physical coalcleaning), but cannot remove organic sulfur. 18

One of the several coal-cleaning processes that removeorganic as well as pyritic sulfur is microwave desulfur-ization. Developed by General Electric, this processbegins by wetting crushed coal with a sodium hydroxidesolution; the mixture is then briefly irradiated withmicrowave energy. During irradiation, the sodium hy-droxide reacts with pyritic and organic sulfur to formsodium sulfide. The coal is immersed in water to removethe sulfur-laden sodium sulfide, and the process is re-peated again. Laboratory tests have achieved total sulfurremovals in excess of 90 percent. 19

Because chemical coal-cleaning techniques are in theearly stages of development, costs are difficult to esti-mate. It is not yet clear whether chemical coal cleaningwill be economically competitive with flue-gas desulfur-ization (described under “Postcombustion Ap-proaches’ in the future. Chemical coal cleaning canbe expected to produce the same side effects-waste dis-

posal requirements, removal of ash and other impurities,increased heating value, and improved boiler effi-ciency— as physical coal cleaning.

OIL DESULFURIZATION

Oil desulfurization is a widely applied method for re-ducing SO2 emissions. The primary method is calledhydrodesulfurization; oil is treated with hydrogen, whichpartially removes the sulfur by combining with it to formhydrogen sulfide gas. Oil is first distilled to separate thecrude into various petroleum products. Most of the sul-fur concentrates in the heavier residues. The lighter frac-tions, or distillate, are redistilled under a vacuum. Inone variant of hydrodesulfurization, referred to as theindirect method, the second distillate is hydrotreated(i.e., reacted with hydrogen) to remove the sulfur as hy-drogen sulfide gas. The product is reblended with thevacuum residue to yield low-sulfur fuel oil. This methodcan reduce the sulfur content by 30 to 42 percent. 20

In another variation of hydrodesulfurization, referredto as the direct method, the residue from distillation ishydrotreated, and then reblended with the distillate toform a lower sulfur fuel, or both the residue and distillatefrom vacuum distillation are separately hydrotreated be-fore relending. This technique can achieve a degreeof desulfurization as high as 70 to 90 percent, but is notyet commercially available. Indirect hydrodesulfuriza-tion is presently the predominant method for produc-ing low-sulfur (less than 1 percent sulfur) fuel oil fromhigh-sulfur crudes. Both the indirect and direct meth-ods are similar to coal cleaning in that the higher thedegree of desulfurization, the higher the costs. Estimatedcosts for desulfurizing oil containing 3-percent sulfurcontent to 1 -percent sulfur content, range from $17 to$40/ton in 1980 prices, depending on the choice of proc-ess.21

Disadvantages of hydrodesulfurization are the highinvestment and operating costs, and the high energy re-quirements. Since fuel oil combustion is not expectedto increase significantly in the United States, the pres-ent desulfurization capacity is expected to remain atcurrent levels for the near future.

Combustion Alteration Approaches

LIMESTONE INJECTIONMULTISTAGE BURNER (LIMB)

Many in the United States consider the LIMB to beone of the most promising control technologies underdevelopment today. The technique controls both SO2

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and NOX emissions. The LIMB is based on the use ofstaged burner techniques for NOX control, in combina-tion with sorbent (normally limestone) which is injectedthrough the burners for SO2 control. SO2 reacts withthe limestone to form solid calcium sulfate.

This technology is still under development; its remov-al efficiencies and costs are very uncertain at this time.Planning goals established by EPA set objectives of 50to 70 percent removal of SO2 and NOX, at a capitalcost of $30 to $40/kW.22 If these goals are achieved, theLIMB would offer substantial cost improvements overexisting technologies. It is very possible that the LIMB,because it may be retrofitted into existing plants at acompetitive cost, may emerge as a particularly attrac-tive control technology option. However, EPA plans tolimit the LIMB research program to basic bench- andlarge pilot-scale R&D through 1985, since funding isunavailable for Government sponsorship of a full-scaledemonstration at this time.23

FLUIDIZED BED COMBUSTION

Another technique that removes SO2 during the com-bustion process is fluidized bed combustion. For thisprocess, crushed coal is fed into a bed of inert ash mixedwith limestone or dolomite. The bed is held in suspen-sion (’ ‘fluidized’ by the injection of air from the bot-tom of the bed. SO2, formed during combustion, reactswith the limestone or dolomite to form solid calcium sul-fate, which can be removed from the boiler without in-terrupting the combustion process.

Fluidized bed combustion can remove up to 90 per-cent of the SO2. Available estimates, though pre-liminary, show the cost effectiveness of fluidized bedcombustion to be about equal to conventional boilersusing flue-gas desulfurization. 24 Further research is stillneeded before large-scale use could be justified; how-ever, for small facilities (up to 250 MW), fluidized bedcombustion is a feasible method today. Oil may also beburned in a fluidized bed, but no such plant is yet inoperation.

Aside from lower emissions, fluidized bed boilers havethe advantages of greater energy efficiency, lower com-bustion temperatures keeping the formation of nitrogenoxides down, and smaller boiler size. Fluidized bed boil-ers can burn both high- and low-sulfur coals.

“James Abbott and Blalr Martin, U S Fmwronmtmtd Prott-[twn Agenc},Research Triangle Park, N C , personal communwatmn

“Julian Jones, U S En\ironmtmtal Protectwn Agency, Research “1’rianglcPark, persona] c ommunic atmn

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Postcombustion Approaches

FLUE-GAS DESULFURIZATION

Flue-gas desulfurization (FGD) technology removesthe SO2 produced during combustion by spraying theexhaust gases in the stack with a chemical absorbent,typically lime or limestone. This process is popularlyreferred to as ‘‘scrubbing. Of the three types of FGDsystems—wet, dry, and regenerable—wet processes aremost widely used. Presently there are over 100 scrub-bers using all three methods in operation in the UnitedStates.

WET SCRUBBERS

The most common absorbents used for wet scrubbingare lime and limestone. The absorbent is dissolved orsuspended in water to form a slurry that can then besprayed or forced into contact with escaping gases. Theslurry converts SO2 into calcium sulfite and calcium sul-fate (gypsum) solids. Limestone scrubbing is the sim-plest, cheapest, and most developed SO2 wet-removalprocess available.

Technology to wet-scrub the flue gas with a lime orlimestone slurry has been commercially available forabout 10 years. As of March 1981, 5.1 percent of in-stalled generating capacity (and 14 percent of coal-firedcapacity) was controlled by wet scrubbers. By 1990, thefigure is projected to increase to 9.4 percent of installedcapacity .25

Wet lime or limestone scrubbers can remove between70 to 90 percent of the SO2 formed during combustion.With the addition of another chemical--adipic acid—re-moval efficiencies can be increased to 95 percent, whilelimestone requirements can be reduced by up to 15 per-cent. 26 However, adipic acid additives may present ad-ditional sludge disposal problems.

A Tennessee Valley Authority (TVA) study con-ducted in 1980 estimated the capital costs of a wet lime-stone system using low-sulfur Western coal (O. 7 percentsulfur, 9,700 Btu/lb) to be $168 to $176/kW. For high-sulfur Eastern coal (3. 5 percent sulfur, 11,700 Btu/lb)capital costs range from $236 to $244/kW. These esti-mates are based on costs for a new 500-MW plant, oper-ating at a 63-percent lifetime capacity. The range in costestimates is due to variations in bids from different con-

)s~l s F.n,.lronrrlenta] Protrx tmn Agcncv. ‘‘ EPA Ullllty F(; D Survt.) (1 -tokJcr-December 1980, EPA-600/7-81 -O12b, ,January 1981,

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tractors and the specific considerations for each site.Annual revenue requirements from the TVA studyrange from 10.5 to 10.9 mills/kWh for low-sulfur coaland 16.4 to 16.7 mills/kWh for high-sulfur coal. 27

The annual revenue requirements for FGD unitsdepend on several factors, including coal sulfur content,size of the unit, age of the plant, and desired percent-age reduction. The costs per ton of sulfur dioxide re-moved by scrubbers rise steeply as the uncontrolledemission rate drops. For example, removing 90 percentof the sulfur from a coal emitting 2 lb of sulfur dioxideper million Btu is about 75 percent more expensive (ona dollar/ton basis) than scrubbing a 4 lb/million Btu coalfor the same size unit. Likewise, scrubbing a 1 lb/mil-lion Btu coal is about 75 percent (or more) costlier thanscrubbing a 2 lb/million Btu coal in a similar unit.

Costs for retrofitting a scrubber onto an existing plantdepend on the lifespan of the plant; the shorter the re-maining lifetime of the plant, the higher the annual rev-enue requirements to recover the capital costs of theFGD. Also, because of economies of scale in construc-tion, retrofitting a scrubber onto a larger unit is less ex-pensive than onto smaller ones. Units smaller than about100 MW are typically quite expensive to retrofit withscrubbers.

Operating problems associated with wet systems arecorrosion/erosion of metal surfaces, scaling (where hardsulfate and sulfite deposits form on equipment), andplugging (where soft deposits form). Ways of minimiz-ing these problems are currently being researched. Inaddition, operation of wet scrubbers requires approxi-mately 3 to 5 percent of a plant’s energy output. 28

The major environmental disadvantage of wet FGDsystems is that they produce large amounts of sludge.Limestone scrubbing produces a compound (mainly cal-cium sulfite and sulfate) that has the consistency oftoothpaste, making it difficult to dewater, store, andhandle. The total amount of FGD waste produced ina typical 1,000-MW plant burning 3.5 percent sulfurcoal is about 225,000 tons annually. A recent report con-cluded that in the future the United States will producemore sludge from FGD scrubbing than from treatingmunicipal sewage. 29

Sludge may, however, be chemically treated to re-duce its water content and improve its compressivestrength. Forced oxidation converts the waste calciumsulfite to calcium sulfate, which precipitates as largecrystals with better settling characteristics. Other means

27”1’ A Burnett, et al , ‘ ‘Spray D~er FGD Technical Rewew and EconomicAsscssmen(, ‘ ‘ “1’ennessee i’alley Authorl[}, presen(ecf a( U S EnvwunmentalPmtertlon Agency Sixth FGD Symposlurn, Houston, ‘1’ex , [)ct 28-31, 1980

‘%’ Ne+lt, ‘‘Scrubhers The Technolog) Nobody W’anted, ” EPR[]o[lr-nal, ~ol 7, No 8 , October 1982

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of improving the sludge’s properties, such as fixationwith lime and fly ash, are still being developed.

Another problem associated with sludge disposal isthe leaching of toxic metals from the residual fly ash intonearby ecosystems. EPA is currently conducting re-search on the characteristics of leaching of metal com-pounds from sludge disposal sites to evaluate the seri-ousness of the problem .30

DRY PROCESSES OF FGD

Dry scrubbers are a new and fast growing segmentof the FGD market. The process involves injection ofa lime slurry or soda ash solution into a spray dryer con-currently with the flue gas. The lime or sodium carbo-nate reacts with the SO2 to form a dry, solid productwhich is subsequently collected along with the fly ashin an electrostatic precipitator or fabric falter (baghouse).

Dry scrubbers offer several advantages over wetscrubbing. Although they generate more waste than wetsystems, they produce a dry waste product that is easierto handle and recycle than wet sludge, and involve sim-pler equipment, less maintenance, lower capital costs,and lower energy requirements. In addition, dry sys-tems require less water than wet systems, and thus areespecially desirable in Western areas of the United Stateswhere water supplies are limited. 31

There are, however, some disadvantages to using adry scrubber over a wet system. First, dry systems re-quire lime, which is more expensive than limestone. Sec-ond, dry scrubbers are in the early stages of commer-cialization and have not demonstrated as high a degreeof removal as wet scrubbers. Their use has generallybeen limited to medium- and low-sulfur coals. However,pilot demonstration and commercial plant tests haveshown sulfur removal efficiencies exceeding 90 percentfor high-sulfur coal.

As of October 1983, six dry scrubber systems werein operation, five at industrial plants, and one at a util-ity plant generating 430 MW of electricity. Four moreunits will be installed on utility boilers in 1984, and ap-proximately 16 units have been ordered for industrialuse.32 A TVA study estimates that capital costs for dryFGD systems range from $144 to $ 160/kW for low-sul-fur Western coal, and from $180 to $188/kW for high-sulfur Eastern coals. Annual revenue requirements areestimated to range from 8.7 to 9.8 mills/kWh for West-ern low-sulfur coal, and 14.5 to 14.9 mills/kWh for high-sulfur coal. These annual costs are between 10 and 25percent lower than wet systems, as reported by the sameTVA study. An EPA survey of dry systems sold to util-

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ities, however, suggests that actual capital costs mightbe lower. Reported capital costs for these systems rangefrom $80 to $130/kW.33

EPA is currently conducting research on the use ofother dry injected minerals to be used in place of lime.If the research results are successful, dry scrubbing costscould be considerably lower than wet systems.

REGENERABLE PROCESSES

Major research efforts by various Government agen-cies have gone into regenerable FGD processes, whichreclaim the SO2 in powerplant flue gases using chemi-cals to produce a marketable product. The major ben-efit of regenerable control systems is that the capturedsulfur can be sold, avoiding waste-disposal problemsassociated with wet and dry processes. Eight regenerableFGD systems are currently operating in the UnitedStates, accounting for about 8 percent of the total FGD-controlled electricity generation. The most prominentregenerable FGD process in use in the United Statesis the Wellman-Lord process. It involves scrubbing theexhaust gas with sodium sulfite solution, resulting insodium sulfite-bisulfite, which is then heated to give offconcentrated SO2 gas that can be used to produce eithersulfuric acid or elemental sulfur. This process is alreadyin use by the New Mexico Public Service Co. One disad-vantage of this process is its high ’energy requirements,which are approximately 8 to 12 percent of boiler energyinput. 34

Other regenerable systems under development are theMagnesia scrubbing process, which produces sulfuricacid, and the Rockwell process, which produces sulfur.Unfortunately regenerable processes cost approximately30 to 50 percent more than nonrecoverable processes.

Controlling NitrogenOxides Emissions

Oxides of nitrogen are formed during combustion bytwo processes. Like sulfur dioxide, NOX are formed asa result of the oxidation of nitrogen present in the fuel(“fuel NO,”). NOX are also formed by the oxidationof nitrogen in the surrounding air (’‘thermal NOX’ ‘).Both processes are controlled by the amount of oxygenpresent; additionally, the thermal NOX formation iscontrolled by temperature. The proportion of thermalto fuel NO, produced during combustion varies fromfuel to fuel. For coal, the Electric Power Research In-stitute estimates that 20 to 40 percent of NOX emissionsare ‘ ‘thermal’ and 60 to 80 percent are ‘ ‘fuel. ’35

‘lU .S Environmental Prott’( tmn Agency, ‘ ‘Survey of Dry S0, Control S)s-

lcrns, 11 I, EPA-60017-81-0973~F:pA.450{3.8 I -004, OP Lit

‘~Ralph W’hltaker, ‘ ‘Trade-offs In NOx Control, EPR1 Journal, to] 7,N(1 1

NOX emissions, being dependent on the amount ofoxygen present and the temperature of the combustionprocess, can be most directly controlled by modifyingcombustion conditions. The majority of NOX controltechniques focus on the combustion process. Postcom-bustion techniques (flue-gas treatment) are also beingdeveloped to achieve even lower emission rates. Todaythe two most promising combustion technologies for re-ducing NOX emissions are certain types of fluidized bedcombustion units, for plants up to 250 MW, and thelow-NO X burner. One precombustion technique, thedenitrogenation of fuel oil, is being researched, but willnot be discussed because of its early stage of develop-ment and limited potential.

Combustion ModificationsThermal NOX formation can be minimized by reg-

ulating the combustion temperature through delayedmixing of fuel and air in the combustion chamber. Lim-iting fuel NOx, is somewhat different, requiring controlof the fuel-air ratio throughout the entire combustionprocess. Two of the major techniques used in combus-tion modification, low excess air (LEA) and low-NOX

burners, are presented below. Other combustion mod-ification techniques include: staged combustion (off-stoichiometric firing), overfire air, flue-gas recirculation,low air preheat, and water injection.36

LEA involves reducing the combustion air to the min-imum amount required for total combustion. Thus, lessoxygen is available for the formation of both thermaland fuel NOX. LEA requires no new hardware and canachieve emissions reductions merely through changesin operating practices. Also, the reduced airflow canimprove boiler efficiency.

The second-generation, low-NOX burners under de-velopment, which employ a staged combustion process,have been shown to significantly reduce the formationof both fuel and thermal NOX in experimental systemsand limited boiler applications. During the first stageof combustion, less air is supplied to the burner thanis required to completely burn the fuel. Fuel-bound ni-trogen is then released— but as nitrogen gas, becauseit cannot be oxidized. The subsequent addition of aircauses the remaining fuel to be burned.

The amount by which NOX emissions can be re-duced depends on very site-specific factors, includingthe type of fuel burned, the type of boiler in use, andthe age of the plant. Installed on an existing coal-firedplant which does not control NOx emissions, the low-NOX burner can reduce NOx emissions by as much as50 percent. Potential NOx emissions reductions fromretrofitting an oil-fired burner range from 60 to 80 per-cent. 37

16A,] An& J,sis ~)f.tht. & Onornic In< ~.nll~.t.s 7’0 Control Emwions [)1’~Vllrw(.n

(1).wies From .Stafionari %ur(es, EPA-WO/7-79- 178[, .Jarruar} 1981 , p A’}.~zF,pA.600/7.7Cj.” 178!. OP ( it


The low-NOX burner can achieve emissions reduc-tion at relatively low cost. Capital costs for coal-firedplants are approximately $1 to $5/kW if integrated intonew boilers, and $2 to $10/kW if retrofitted onto existingplants .38

Potential problems such as corrosion and high main-tenance requirements could delay large-scale use of thelow-NOX burner. Retrofitting old boilers can be diffi-cult, but NOX controls on new boilers can be made anintegral part of boiler design without adding substan-tially to cost.

Another combustion modification approach for thecontrol of NOX is the LIMB, which is discussed infurther detail in the section on combustion alterationapproaches for SO2. EPA research goals for the LIMBare to achieve a 50- to 70-percent removal of SO2 andNOx, at a cost of $30 to $40/kW; however, the LIMBis not expected to be commercially available for about3 to 5 years.39

Postcombustion Approaches

FLUE-GAS TREATMENT

Flue-gas treatment (FGT) is an emerging postcom-bustion process for high levels of NOX removal. FGT

‘S II)I(l“,]amu Abbott and Blalr \lartln, L“ S En\lronmen[al Prote( tlon Agency,

Rrw~r( h ‘1’rlanqlc Park, N (; , person<~] cornrnunicatlon

has been developed and applied extensively in Japanfor use on oil-fired boilers. But due to its operationalcomplexities and high costs for use on coal-fired boilers,FGT has not become as popular as the low-NOX

burner in the United States.At least 50 different types of FGT technologies are

available today. Of these, selective catalytic reduction(SCR) achieves the highest reductions. SCR is a dryprocess, produces no solid waste, and in most cases canbe retrofitted to existing burners. In SCR, flue gasesare mixed with ammonia and then passed over a cata-lyst. The catalyst assists in the reaction of ammonia andNOx to form nitrogen gas and water vapor. While 90-percent NOX removal during combustion is possible,80-percent removal is preferable in order to minimizecapital and operating costs and maximize the burners’reliability and lifespan. One estimate places the costsof FGT at between $75 and $100/kW for a 60- to 80-per-cent reduction in NOX emissions .40

Two problems associated with SCR are the disposalof spent catalysts, such as vanadium and titanium, andthe condensation of bisulfate and bisulfite residuals ontoequipment .41

~OEpRI Journal, op. ~~t

“j D. Moble), Assessment o f NO~ F-Iuc Gas Trc>amwrl ‘1’elhrr(Jw. ~T s

Enwronmental Protection Agem ), Research Triangle Park, prmmrted al S} n-poslum nf Stationary Combustion NO, Control, Denwr, Colo , (1 tober 1980

A.3 ALLOCATION OF SULFUR DIOXIDE EMISSIONSREDUCTIONS AND THE COSTS OF CONTROL

Introduction

The costs and distributional consequences of variouscontrol strategies are important factors in decisionsabout controlling transported air pollutants. Costs areaffected both by the amount of emissions to be elimi-nated, and by the manner in which emissions reduc-tions are to be achieved. For a given emissions reduc-tion strategy, the greater the reduction, the greater thecost. For a given emissions reduction target, alternativeimplementation strategies may entail different costs, i.e. ,one strategy may be more cost effective than another.

Alternative control strategies may also have differentdistributional consequences. Certain approaches assigna greater share of the emissions reduction burden to oneregion or State or economic sector than to others. Thissection examines the costs and distributional conse-

quences of various emissions reduction strategies, con-centrating on emissions reductions in the Eastern 31-State region. Due to analytical limitations, only thecosts of reducing sulfur dioxide (SO2) emissions fromutilities are presented.

SO2 emissions for 1980 are estimated to be about 26million tons nationwide and about 22 million tons inthe Eastern 31 States. Fossil fuel combustion by elec-tric utilities accounts for about 17 million tons or 65 per-cent of the national total. In the Eastern 31 States, util-ities produce 70 percent of the regional SO2 emissions,or about 16 million tons. Under current regulations,EPA-approved State implementation plans (SIPS) re-quire utilities to reduce these emissions by approx-imately 1 million tons.

OTA has estimated the cost of further reducing util-ity SO2 emissions in the 31 -State region below the SIP-

99-413 0 - 84 - 12 : QL . 3

168. Acid Rain and Transported Air Pollutants: Implications for Public Policy

Figure A-5.—Comparison of Utility SO2 Control Costs

SO2 reductions (million tons/year, after SIP compliance)

SOURCE: Office of Technology Assessment from references listed in text.

compliance level under several different control strate-gies. The model used in generating these estimates isdescribed briefly at the end of this section. *

The Costs of Various Levelsof Emissions Reductions

To illustrate how the extent of emissions reductionsaffects the costs of controlling emissions, figure A-5displays estimates of 31-State aggregate control costs

● This analysis uses the AIRC;OSrI” model, run by E. H. Pechan & Assrxiates,Inc AI RCOST was modified from a larger model used in several earlier majorassessments, including the New Source Performance Standards (NSPS) review,the Obio River Basin Fmergy Study (OR BES), and tbe Acid Rain M ltigatlonStudy (ARMS)

made by OTA and several other groups. * * Costs arepresented for reducing SO2 emissions from utilities only,and are in 1982 dollars. To reduce emissions by approx-imately 5 million tons beyond SIP compliance, the vari-

“ “Most uf tbese cost estimates are cited in ‘ ‘Costs TO Redu( e Sulfur D]-oxide Emwons,” Department of Energy, DOE/PE-0042, 1!%2. DOE adjustedeach estimate using consistent economic assumptions, Cost esttmates are also

included from: “Summary of Acid Rain Analyses LTndertaken by ICF for theE[fison Electric Insltute, Nation~ W’i]d]lfe Federation, and Envir(Jnment~ pro.tectlon Agency, prepared by ICF, In{,, for the Edison Electric Institute, 1982;and Chris Farrand, Peabody Coal Co , test imony before the Senate Environ-ment and Public Works Committee, October 1981. O’I’A estimates are bdsr’cfon analyses prepared by E H Pec han & Associates, Inc. , 1983. The PEDCOstudy was preparmf for DOE, the Teknekron anal)sls was prepared for EPAand DOF., and the ICF analyses were performed for EPA, DO F., the E{ilsorsElectric Institute, and the National Wildlife Federation C)”I’A’s estimates arepreseoteci as the costs of’ reductions beyond SIP compliance. “1’he Peabody,PIIDC(j, and DOE estimates are reductions below actual 1980 cmlssinns, amftbe ICF and Teknekron model est irnates are displayed as emissions redu( t Ionsbelow proie[ ted 1990 crmssions levels


ous estimated annual costs range from about $1 to $2billion per year. For reductions of 8 million tons beyondSIP compliance (about 55 to 60 percent below currentutility emissions), the range increases to $2 to $3.5 bil-lion annually. The largest emissions reduction calcu-lated—a 13-million-ton reduction below projected 1990levels— is estimated to cost approximately $7 billion peryear.

Table A-7 displays OTA’s control cost estimates fora series of emission rate limitations ranging from 0.8to 2.5 lb of SO2 emitted per million Btu (MMBtu) offuel burned. Eastern 31 -State emissions reductionsrange from 4.6 million to 11.4 million tons per year,including reductions already required under currentlaw. However, the costs presented consider only thosereductions that would be required beyond SIP com-pliance.

For each emission rate limitation, two sets of cost es-timates are presented. The cost estimates in the top halfof the table assume that each utility chooses the leastexpensive control method among those applicable toplant conditions. This typically results in a statewidemix of coal washing, switching to (or blending with) low-er sulfur fuels, and wet and dry scrubbers. Cost esti-mates presented in the bottom half of table A-7 assumethat the legislation mandates the use of pollution con-trol technologies such as wet scrubbers. Several recentbills have included such a control technology restrictionto minimize job dislocations among high-sulfur coal

miners. (Section A.5 of app. A discusses the magnitudeof potential coal production and related employmentchanges due to acid rain control legislation. )

As expected, costs increase as emissions reduction re-quirements increase. As shown in the top-half of tableA-7, the ‘ ‘least-cost’ method of control ranges from lessthan $1 billion annually to eliminate less than about 5million tons per year, to between $4 and $5 billion toeliminate 11.4 million tons. * Moreover, the marginalcosts of control increase when larger emissions rollbacksare required. That is, the cost of eliminating an addi-tional 1 million tons of SO2 per year is greater for anincrease from 8 million to 9 million tons (approximate-ly $700 million per year) than for an equal increase from7 million to 8 million tons (approximately $450 millionper year).

As shown in the bottom half of table A-7, mandatingthe use of control technology to achieve all requiredemissions reductions increases the cost of control. Foremissions reductions in the range of 5 million tons peryear, such a requirement about doubles control costs.For greater levels of emissions reductions (9 million to

“All { ost cstlmatcs are first -)eari annualized costs In 1982 {io]ldr~ ( :<ipItalcosts and Interest payments are spread cvenlv o\ cr each ~,t.w of the Ille (If t Ilt,In\cstmcnt Bec ausc fuel and operation dnd nlaln[enan( t. ( c~it \ ( ~n \ ar) fl on)vcar to year ( i e . real energy and labor { f)sts might either II]( reaw or [!e( reaw.over the next two decades), current Iuel anci operation” an(i maln[enancc [ osts( rather than an atvragc based on assume(i [ren(ii) art, ,i(i(ieri t,] [ aplt,d ( (JSISt<) { alc uiatc yearl) total cr)nl r(]i costs

Table A-7.—Costs of Reducing SO2 Emissions in the Eastern 31 States (excludes costs to meet current SIPS or tooffset future emissions growth; all costs in 1982 dollars)

A. Assuming each utility chooses the most cost-effective control method:

Emission rate Emissions Average cost Marginal costlimitation reduction Total cost of reductions of reductions

(lb SO,/MMBtu) (million tons S0,) (billions of dollars/yr) % ($/ton) ($/ton)

2.5 4.6 $0.6-0.9 $170-240 $3202.0 6.2 1.1-1.5 200-280 4401.5 8.0 1.8-2.3 260-330 7001.2 9.3 2.6-3.4 310-400 7401.0 10.3 3.2.4.1 350-440 8300.8 11.4 4.2-5.0 400-480 1,320

B. Assuming utilities are required to install control technology (wet scrubbers):Emission rate Emissions Average Cost Increased costs due to control

Iimitation reduction Total costb of reductions technology requirement(lb SO2/MMBtu) (million tons SO2) (billions of dollars/yr) ($/tons) (billions of dollars/yr) (percent increase)

2.5 4.6 1.4 360 0.7 1102.0 6.2 2.0 380 1.0 901.5 8.0 3.1 430 1.2 701.2 9.3 4.0 480 1.4 551.0 10.3 4.8 510 1.6 500.8 11.4 5.9 570 1.8 40

aCost (in dollars per ton) to achieve the next increment of reductions.bAssumes statewide emissions reductions are from those utility plants that can install scrubbers most cost effectively. Old and Small Units are exempt from the require-

ment to install scrubbers, but equivalent emissions reductions are obtained from other plants within each State,cCompared to "least cost’ estimate in part A of this table

SOURCE Office of Technology Assessment, based on analyses by E H. Pechan & Associates, Inc.

170 . Acid Rain and Transposed Air Pollutants: Implications for Public Policy

11 million tons per year), mandating the use of scrub-bers increases total control costs by about 50 percent.

State-by-State Emissions Reductionsand Costs of Control Strategies

Thus far, only aggregate, regional control cost esti-mates have been presented. Costs of control would varyconsiderably from State to State, depending on eachState’s emissions reduction requirements, and the costsof available emissions reductions in each State. The spe-cific control strategy chosen affects both regional costsand their State-by-State distribution.

Actual State-level costs are determined by: 1) theamount of reductions allocated to each State, which de-pends on the chosen control strategy; and 2) the costsof available emissions reduction opportunities in eachState, which depend on the type and number of electric-generating plants in service, and their levels of currentemissions. States which already have relatively low util-ity emissions rates may not have as many opportunitiesto use less expensive control options as States with higheremissions rates. The latter States may be able to achieverelatively large reductions at lower costs per ton.

Table A-8 presents data on utility SO2 emissions andelectricity generation. The first column displays 1980utility SO2 emissions by State; the second column ranksthe 30 highest emitting States according to these emis-sions. States that generate more electricity from fossil-fuel-fired utilities would be expected to emit more SO2

(all other factors being equal); thus, columns 3 and 4present 1980 fossil-fuel-generated electricity and corre-sponding rank for the top 30 States. The last two col-umns present average SO2 emissions rates—the quan-tity of SO2 emitted per million Btu of fuel burned, andthe corresponding rank of States with average utilityemissions rates greater than or equal to 1.2 lb/MMBtu.In general, the higher the emissions rate, the greaterthe opportunity for reducing emissions and the lowerthe cost per ton of SO2 removed.

However, statewide average emissions rates mask thevariation among plants within a given State. Table A-9 examines the potential for reducing utility SO2 emis-sions in each State in greater detail. The table displaysthe percentage of utility emissions that could be elimi-nated by mandating various emissions rate limitations,ranging from 1.0 to 4.0 lb of SO2 per million Btu offuel burned. These estimates are calculated by assum-ing no facility may exceed the specified emissions rate.

Table A-10 displays the average cost, in dollars pertons of SO2 removed, for reducing utility SO2 emissionsby 50 percent in each of the Eastern 31 States. Whilemuch of the State-level variation is due to differences

in emissions rates, considerable variation results fromsuch other factors as distance from low-sulfur coal sup-plies, dependence on oil, and size and age of the utilityplants.

Comparison of Alternative Approachesto Emissions Reductions

OTA has analyzed a number of approaches to allo-cating an 8-million-ton reduction of utility SO2 emis-sions among the Eastern 31 States. The regional costsand distributional consequences of eight different alloca-tion formulae —in terms of the reductions allocated toeach State and the cost of achieving those allocated re-ductions —are discussed below.

Table A-11 presents the overall cost of these eight al-ternative allocation approaches for the 31 -State region.The costs are shown to range from a low of $1.8 billionto $2.3 billion per year for reductions based on a maxi-mum emissions rate (1. 5 lb of SO2 per MMBtu) to ahigh of $3.7 billion to $3.9 billion per year for an alloca-tion formula based on total SO2 emissions per land area.Each approach eliminates about 8 million tons of SO2

per year; future emissions growth—estimated to beabout 1 million to 2.5 million tons per year by 1995—is not offset. Cost to achieve emissions reductionsalready required under current regulations (SIPS) arenot included.

Table A-12 shows the State-by-State emissions reduc-tions required under each allocation approach; tableA-13 estimates State-average control costs, expressed asa percentage of residential electricity costs. Some Statesare consistently allocated relatively large costs— in par-ticular, Georgia, Indiana, Kentucky, Missouri, NewHampshire, Ohio, Pennsylvania, and West Virginia.For other States—e. g., Delaware, New Jersey, andRhode Island—control costs are strongly influenced bythe allocation approach used. The approaches that al-locate the widest State-by-State variations in requiredemissions reductions—e. g., those based on emissionsper person or land area—cause State-level costs to varya great deal. In these cases, some States are allocatedvery large costs and others incur no costs at all.

These estimates illustrate that both the regional andState-by-State costs of control depend on the way inwhich emissions reductions are allocated to States.Therefore, the choice of allocation policy involves boththe political issue of who should bear the burden of re-ducing emissions as well as the national economic issueof total cost.

A later section of’ this appendix (A.4) discusses an al-ternative method of allocating control costs. A trust fundbased on a tax on emissions or electricity generationcould be established to help pay for part of the costs of

App. A—Emissions and the Costs of Control 171

Table A-8.—Fossil-Fuel-Fired Electric Utilities: S02 Emissions, Electricity Generated,Average S02 Emission Rate, 1980

Electricity generationUtility S02 emissions (fossil-fuel-fired) S 02 emission rate

State 103 tons/yr Rank (top 30) 10 9 kWh/yr Rank (top 30) lb/MMBtu Rank (top 30)Alabama . . . . . . . . . . . . . . . . 543.1Alaska. . . . . . . . . . . . . . . . . . 11.7Arizona . . . . . . . . . . . . . . . . . 87.5Arkansas . . . . . . . . . . . . . . . 26.6California . . . . . . . . . . . . . . . 77.9Colorado. . . . . . . . . . . . . . . . 77.5Connecticut . . . . . . . . . . . . . 32.1Delaware . . . . . . . . . . . . . . . 52.5District of Columbia. . . . . . 4.6Florida . . . . . . . . . . . . . . . . . 725.9Georgia. . . . . . . . . . . . . . . . . 736.7Hawaii . . . . . . . . . . . . . . . . . . 41.6Idaho. . . . . . . . . . . . . . . . . . . 0,0Illinois. . . . . . . . . . . . . . . . . . 1,125.6Indiana , . . . . . . . . . . . . . . . . 1,539.6lowa . . . . . . . . . . . . . . . . . . . 231.3Kansas . . . . . . . . . . . . . . . . . 150.1Kentucky . . . . . . . . . . . . . . . 1,007.5Louisiana . . . . . . . . . . . . . . . 24.8Maine . . . . . . . . . . . . . . . . . . 16.3Maryland . . . . . . . . . . . . . . . . 223.2Massachusetts . . . . . . . . . . 275.5Michigan . . . . . . . . . . . . . . . 565.4Minnesota . . . . . . . . . . . . . . 177.4Mississippi, . . . . . . . . . . . . . 129.2Missouri . . . . . . . . . . . . . . . . 1,140,5Montana . . . . . . . . . . . . . . . . 23.4Nebraska . . . . . . . . . . . . . . . 49.5Nevada . . . . . . . . . . . . . . . . . 39.5New Hampshire . . . . . . . . . 80.5New Jersey . . . . . . . . . . . . . 110.2New Mexico . . . . . . . . . . . . . 84.6New York . . . . . . . . . . . . . . . 480.3North Carolina . . . . . . . . . . . 435.4North Dakota . . . . . . . . . . . . 82.5Ohio . . . . . . . . . . . . . . . . . . . 2,171.6Oklahoma . . . . . . . . . . . . . . . 37.7Oregon . . . . . . . . . . . . . . . . . 3.3Pennsylvania . . . . . . . . . . . . 1,466.1Rhode Island . . . . . . . . . . . . 5.2South Carolina . . . . . . . . . . 213.1South Dakota . . . . . . . . . . . . 28.6Tennessee . . . . . . . . . . . . . . 933.7Texas . . . . . . . . . . . . . . . . . . 302.8Utah . . . . . . . . . . . . . . . . . . . 22.1Vermont . . . . . . . . . . . . . . . . 0.5Virginia . . . . . . . . . . . . . . . . . 163.7Washington . . . . . . . . . . . . . 69.4West Virginia. . . . . . . . . . . . 944,2Wisconsin . . . . . . . . . . . . . . 485.7Wyoming . . . . . . . . . . . . . . . 120.9

National totals . . . . . . . . . 17.378.5

12

27

109

52

1823

6

1917112124

4

302628141529

1

3

20

816

22

71325

45.42.6

27.010.289.621.212.66.70.7

79.050.5

6.50.0

75.770.118.325.154.245.8

2.120.031.657.921.018.548.4

5.59.3

11.75.1

22.124.663.260.811.8

108.143.3

0.8109.7

1.021.5

2.851.0

201.911.30.0

21.97.3

70,426.022.8

1.754.4

17

20

428

514

68

221216

30191129

15

2723

910

318

2

26

131

25

72124

2.30.60.60.50.20.70.51.51.01.72.91.20.02.74.22.21.03.60.11.42.11.81.81.51.34.50.71.00.62.90.90.61.41.51.23.80.20.72.51.01.91.73.70.30.41.21.41.72.73.41.0

1.9

12

21

187

28

92

13

5

241416162127

7

242128

3

11

1518

4

28241896

SOURCE: E. H. Pechan &. Associates, inc., ’’Estimates of Sulfur Oxide Emissions From the Electric Utility Industry;’ prepared for the Environmental Protection Agency, 1982,


Table A-9.-SO2 Emission Reductions Achieved by Emission Rate Limitations(percent reduction in 1980 utility SO2 emissions)

SO2 emissions Percent reduction with emission limit (lb SO2/MMBtu)

State (103 tons) 1.0 1.2 1.5 2.0 2.5 3.0 4.0

Alabama. . . . . . . . . . . . . . . . . . . . . . . . . . .Alaska . . . . . . . . . . . . . . . . . . . . . . . . . . . .Arizona. . . . . . . . . . . . . . . . . . . . . . . . . . . .Arkansas . . . . . . . . . . . . . . . . . . . . . . . . . .California. . . . . . . . . . . . . . . . . . . . . . . . . .Colorado . . . . . . . . . . . . . . . . . . . . . . . . . .Connecticut . . . . . . . . . . . . . . . . . . . . . . .Delaware . . . . . . . . . . . . . . . . . . . . . . . . . .District of Columbia . . . . . . . . . . . . . . . .Florida . . . . . . . . . . . . . . . . . . . . . . . . . . . .Georgia . . . . . . . . . . . . . . . . . . . . . . . . . . .Hawaii . . . . . . . . . . . . . . . . . . . . . . . . . . . .Idaho . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Illinois . . . . . . . . . . . . . . . . . . . . . . . . . . . .Indiana . . . . . . . . . . . . . . . . . . . . . . . . . . . .lowa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Kansas . . . . . . . . . . . . . . . . . . . . . . . . . . . .Kentucky . . . . . . . . . . . . . . . . . . . . . . . . . .Louisiana . . . . . . . . . . . . . . . . . . . . . . . . . .Maine ............,.. . . . . . . . . . . . . . .Maryland . . . . . . . . . . . . . . . . . . . . . . . . . .Massachusetts . . . . . . . . . . . . . . . . . . . . .Michigan . . . . . . . . . . . . . . . . . . . . . . . . . .Minnesota . . . . . . . . . . . . . . . . . . . . . . . . .Mississippi . . . . . . . . . . . . . . . . . . . . . . . .Missouri . . . . . . . . . . . . . . . . . . . . . . . . . . .Montana . . . . . . . . . . . . . . . . . . . . . . . . . . .Nebraska . . . . . . . . . . . . . . . . . . . . . . . . . .Nevada . . . . . . . . . . . . . . . . . . . . . . . . . . . .New Hampshire . . . . . . . . . . . . . . . . . . . .New Jersey . . . . . . . . . . . . . . . . . . . . . . . .New Mexico . . . . . . . . . . . . . . . . . . . . . . .New York . . . . . . . . . . . . . . . . . . . . . . . . . .North Carolina . . . . . . . . . . . . . . . . . . . . .North Dakota . . . . . . . . . . . . . . . . . . . . . .Ohio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Oklahoma . . . . . . . . . . . . . . . . . . . . . . . . .Oregon . . . . . . . . . . . . . . . . . . . . . . . . . . . .Pennsylvania . . . . . . . . . . . . . . . . . . . . . . .Rhode island . . . . . . . . . . . . . . . . . . . . . . .South Carolina . . . . . . . . . . . . . . . . . . . . .South Dakota . . . . . . . . . . . . . . . . . . . . . .Tennessee . . . . . . . . . . . . . . . . . . . . . . . . .Texas . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Utah . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Vermont . . . . . . . . . . . . . . . . . . . . . . . . . . .Virginia . . . . . . . . . . . . . . . . . . . . . . . . . . .Washington . . . . . . . . . . . . . . . . . . . . . . . .West Virginia . . . . . . . . . . . . . . . . . . . . . .Wisconsin . . . . . . . . . . . . . . . . . . . . . . . . .Wyoming . . . . . . . . . . . . . . . . . . . . . . . . . .

United States . . . . . . . . . . . . . . . . . . . .

54312882778773252

5726737

420

1,1261,540

231150

1,0082516

223276565177129

1,14123493980

11085

480435

822,172

383

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10SOURCE: E. H. Pechan &Associates, inc., ’’Estimates of Sulfur Oxide Emissions From the Electric Utility lndustry;’ prepared for the Environmental Protection Agency, 1982.


Table A-10.—Statewide Average Cost ofReducing Utility S02 Emissions by 50 Percent

(dollars/ton SO2 removed, 1982 dollars)

Alabama . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300-500Arkansas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . >1,500Connecticut . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . >1,500Delaware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 750-1,000District of Columbia . . . . . . . . . . . . . . . . . . . . . . . >1,500Florida . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 350-450Georgia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400-550Illinois . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250-350Indiana . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150-200Iowa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100-250Kentucky . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300-450Louisiana . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1,000-1,500Maine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1,000-1,500Maryland . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ‘550-600Massachusetts. . . . . . . . . . . . . . . . . . . . . . . . . . . .Michigan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Minnesota. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Mississippi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Missouri . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .New Hampshire . . . . . . . . . . . . . . . . . . . . . . . . . . .New Jersey. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .New York . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .North Carolina . . . . . . . . . . . . . . . . . . . . . . . . . . . .Ohio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Pennsylvania . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Rhode Island . . . . . . . . . . . . . . . . . . . . . . . . . . . . .South Carolina . . . . . . . . . . . . . . . . . . . . . . . . . . . .Tennessee . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Vermont . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Virginia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .West Virginia.. . . . . . . . . . . . . . . . . . . . . . . . . . . .Wisconsin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

31-State reason . . . . . . . . . . . . . . . . . . . . . . . . . .

950-1,000300-450500-700250-300

<150500-600700-800700-800750-900200-300450-500>1,500450-800

<150—a

900-1,100450-500

<150320-410

a$ton costs not estimated

SOURCE: Office of Technology Assessment, based on analyses by E. H. Pechan&Associates, Inc.

Table A-11 .—Regional Costs of Alternative Approaches to Allocating an 8-Million.Ton Reductionin S02 Emissions (Eastern 31-State control region, ali costs in 1982 dollars)

SO2 reduction Regional costsa

Allocation approachb (milliontons/yr) (billions of dollars/yr) ($/ton)

I. Allocation based on utility SO2 emissions:1. 50% reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.3-2.9 320-4102.1.5 lb/MMBtu rate limitation . . . . . . . . . . . . . . . . . . . . . . . . . 8 1.8-2.3 255-3253. Lower of:

1.2 lb/million Btu rate limitation or 50% reduction . . . . . . 7.5 1.8-2.4 275-3704. 1.3 lb/million Btu average . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 1.8-2.4 260-3405.11 lb/MWhr (total) average . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 1.9-2.5 270-350

Il. Allocation based on total SO2 emissions:1. 35% reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.6 2.6-3.1 385-4652. 16 tons/square mile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.7-3.9 560-5853. 200 lb/person . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.6-3.0 370-415

aCosts precalculated on the basis of emissions reductions below SIP compliance levels.bAlternative approaches explained in text.

SOURCE Office of Technology Assessment, based on analyses by E. H. Pechan &Associates, Inc

Table A.12.—Emissions Reductions Required by Alternative Allocation Approaches—.

1: Formulae based on utility S02 emissions

(percent below 1980 emissions)

Lower of:1.2 lb/MMBtu cap,

500/0 reduction 1.5 lb/MMBtu cap 50°/0 reduction 1.3 lb/MMBtu avg. 11 lb/MWhr avg.

Percent below: Percent below: Percent below: Percent below: Percent below:State Utility Total UtilityAlabama . . . . . . . . . . . .Arkansas . . . . . . . . . . . .Connecticut . . . . . . . . .Delaware . . . . . . . . . . . .District of Columbia. . .Florida . . . . . . . . . . . . . .Georgia . . . . . . . . . . . . .Illinois . . . . . . . . . . . . . .Indiana . . . . . . . . . . . . .lowa . . . . . . . . . . . . . . . .Kentucky. . . . . . . . . . . .Louisiana . . . . . . . . . . .Maine. . . . . . . . . . . . . . .Maryland . . . . . . . . . . . .Massachusetts. . . . . . .Michigan . . . . . . . . . . . .Minnesota. . . . . . . . . . .Mississippi . . . . . . . . . .Missouri . . . . . . . . . . . .New Hampshire . . . . . .New Jersey . . . . . . . . . .New York. . . . . . . . . . . .North Carolina . . . . . . .Ohio . . . . . . . . . . . . . . . .Pennsylvania . . . . . . . .Rhode Island. . . . . . . . .South Carolina . . . . . . .Tennessee. . . . . . . . . . .Vermont. . . . . . . . . . . . .Virginia . . . . . . . . . . . . .West Virginia . . . . . . . .Wisconsin . . . . . . . . . .E a s t e r n 3 1 - S t a t e s . .

505050505050505050505050505050505050505050505050505050505050505050

35 3813 3522 024 4415 033 3443 4738 5838 6535 4644 58

4 08 8

33 3440 2431 3134 2422 4443 6743 4719 2425 3336 441 6236 4417 032 2943 59

3 022 343 4938 6037 50

Total Ut i l i ty Tota l Ut i l i ty Tota l Utility Total. .27 48

9 350 0

21 440 0

22 4341 5044 5050 5032 5052 50

0 01 15

22 4519 3519 3916 3320 5059 5041 50

9 3217 43

2 1850 5032 50

0 019 4151 50

0 41 15

43 5045 5037 47

35 429 350 0

21 440 0

28 2443 5338 5138 6735 4044 62

0 02 8

30 3828 2524 2823 1322 043 6943 5312 022 713 1141 6536 48

0 027 3243 63

0 06 5

43 5138 6035 50

SOURCE. Office of Technology Assessment, based on analyses by E. H Pechan & Assoclates, Inc

30 209 350 0

21 440 15

16 2647 5139 4752 7228 4656 66

0 01 0

25 2020 2717 25

9 20 20

61 7346 57

0 03 18 8

53 6934 51

0 021 055 61

0 02 2

44 5646 5537 50

1490

214

174436553259

00

132215

:6449

006

5737

00

5301

494237

II: Formulae based on total S02 emissions(percent below 1980 emissions)

35% reduction 16 tons/mi2

——— 200 lb/person

Percent below: Percent below: Percent below:, ut i l i ty tota l UtiIity

4 8> 1 0 0

7873

>100523 94 54 5493 8

> 1 0 0>100

534 35651773 9408868484248

>1005340

>10077404548

3 5 43 5 3 53 5 03 5 > 1 0 03 5 > 1 0 03 5 213 5 03 5 5035 9335 035 4735 035 035 7535 7735 035 035 035 1635 335 >10035 3135 035 9135 8835 035 035 4335 035 235 7435 035 50

Total UtiIity3 6 59 3 50 0

70 9093 014 16

0 3838 2771 900 15

42 710 00 0

5061 20

o 00 00 24

14 673 3

55 016 1

0 375 6964 54

0 00 6

37 630 01 2

64 900 32

37 50

Total

4 690

4 30

1033216 9106 4

002

1600

115 9

3002

5 63 9

04

5 401

7 82 53 7


Table A-13.—Costs of Alternative Allocation Approaches(estimated percentage increase in residential electricity rates, assuming all emissions reductions from utilities)

500/0 1.2 lb/MMBtu 35 ”/0reduction 1.5 lb/M MBtu cap or 50°/0 1.3 lb/MMBtu 11 lb/MWhr reduction 16 tons/ 200 Ib/

(utility) cap reduction average average (total) Mi2 person. . . . ● ☛ ☛ ☛

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SOURCE Off Ice of Technology Assessment, based on analyses by E.H. Pechan and Associates, Inc

control. Costs could then be distributed to a larger groupthan those required to reduce emissions under each ofthe scenarios discussed below.

Key aspects of each allocation approach—includingits rationale, costs, and distributional consequences—are outlined below.

1. Equal percentage reduction in each State—utility emissions only.Description: Each State is required to reduce itsutility S02 emissions by an equal percentage.Rationale: Requiring an equal percentage reduc-tion in utility S02 emissions distributes relativeemissions reductions fairly uniformly amongStates.

Formula for achieving an 8-million-ton reduction:Eliminating 50 percent of 1980 utility emissionsin each of the Eastern 31 States.Cost: Reducing utility S02 emissions by 50 per-cent in each State is estimated to cost $2.3 to $2.9billion annually, at an average cost of $320 to $410per ton of S02 removed (1982 dollars).Distributional consequences: This formula re-quires an equal percentage reduction from eachState regardless of: 1) the relative costs of emis-

sions control, or 2) the stringency of the State’sexisting emissions regulations. Five States—Arkansas, Connecticut, Louisiana, Maine, andRhode Island—would not be able to reduce util-


2.

3.

ity emissions by the necessary 50 percent with-out setting extremely stringent emission rate lim-itations (less than 0.4 lb/MMBtu of SO2).

Utility emission rate limitation (limiting emis-sions per fuel burned).Description: This approach sets some maximumemissions limits (an emissions ‘‘cap’ for each fos-sil-fuel electric-generating plant. In this case, thelimit is an emissions rate specifying the amountof allowable emissions per quantity of fuel burned.Rationale: Setting an emissions cap would requireemissions reductions in States with powerplantsemitting over a certain rate. It would thus targetStates with plants emitting large quantities of S02

per quantity of fuel burned, but not penalizeStates simply for generating large quantities ofelectricity.Formula for achieving an 8-million-ton reduction:Limiting emissions rates for all plants in the East-ern United States to 1.5 lb of S02 per MMBtuof fuel burned.Cost: Estimated annual costs under this approachare $1.8 to $2.3 billion, at an average cost of $255to $325/ton.Distributional consequences: The largest costs andpercentage reductions are distributed to Stateswhose plants emit relatively large amounts of pol-lutants per unit of energy consumed—e. g., Mis-souri, Indiana, Ohio, and Tennessee. States withplants emitting at low rates (usually through theuse of less polluting fuels, e.g., oil and naturalgas) —e. g., Louisiana, Arkansas, and Connecticut—are allocated the smallest reductions.

Utility emission rate limitation, with a max-imum reduction of 50 percent below currentutility emissions.Description: This approach modifies the cap ap-proach by limiting any State’s required reductionsto 50 percent of 1980 utility emissions.Rationale: By placing a ceiling on reductions, thisapproach reduces the impact on those States mostheavily targeted under a cap approach. It reducesregional variations in cost by setting a maximumrelative reduction requirement for all States.Formula for achieving a 7.5-million-ton reduc-tion: A cap of 1.2 lb of S02 per MMBtu, witha maximum reduction of 50 percent below 1980emissions for each State. An alternative methodof stating the formula is a 50-percent reductionin a State’s 1980 utility emissions, but requiringno existing source to reduce emissions below 1.2lb of S02 per MMBtu. Thus, the formula achievesless than the 8-million-ton reduction of the firstallocation approach.

4.

5.

Cost: This approach is estimated to cost between$1.8 and $2.4 billion per year, at an average costof $275 to $370/ton.Distributional consequences: By placing a limiton percentage reductions, this approach lessensthe impact on States required to reduce the mostunder a cap approach. The States that benefit bythis approach as compared to a simple emissionscap are Indiana, Kentucky, Missouri, and Ohio.Average utility emissions per fuel burned.Description: Each State is required to achieve aspecified average utility emissions rate. Underthis averaging approach, some plants within aState are allowed to exceed the specified emissionsrate (unlike the cap case) as long as the State hascompensating plants emitting below the rate.Rationale: Unlike the cap, the average emissionrate approach gives credit to States with plantsemitting below the specified emissions rate.F o r m u l a f o r a c h i e v i n g a n 8 - m i l l i o n - t o n r e d u c t i o n :

Each State is required to eliminate sufficient emis-sions to achieve a statewide utility emissions aver-age of 1.3 lb of S02 per M MBtu of fuel burned(based on 1980 emissions).Cost: This strategy is estimated to cost $1.8 to$2.4 billion per year at an average cost of $260to $340/ton.Distributional consequences: Emissions reduc-tions are allocated in a manner similar to the capcase. States in which a substantial number ofplants emit at rates below the specified average(e. g., New York, Minnesota, and Mississippi)would tend to prefer the average rate approachover the cap; States in which most plants emit atrates well above the average used for allocation(e.g., Missouri and Kentucky) would tend to favorthe cap over the average (assuming that identicalregional reductions are required).Average utility emissions per total electricityouput.Description: This approach allocates emissions re-ductions on the basis of the amount of S02 emit-ted per unit of electricity generated by all plants,including hydroelectric and nuclear powerplants,Rationale: Allocating emissions reductions on thebasis of total electricity generation gives credit tothose States that generate electricity with fuels thatdo not produce S02 emissions.Formula for achieving an 8-million-ton reduction:States are required to reduce utility emissions tomeet an average rate of 11 lb of S02 per mega-watt-hour of total electricity output.Cost: This approach is estimated to range in costfrom $1.9 to $2.5 billion annually, at an averagecost of $270 to $350/ton of S02 reduced.

App. A—Emissions and the Cosfs of Control ● 177

6.

7.

Distributional consequences: This approachfavors States in which relatively high proportionsof electricity produced by hydroelectricity or nu-clear power—e. g., Alabama, Maine, Maryland,Minnesota, and New York.Equal percentage reductions in each State—total SO2 emissions.Description: Each State is required to reduce totalS02 emissions (i. e., emissions from all sectors,not just utility emissions) by an equal percent-age from some baseline level.Rationale: Each State participates equally in re-ducing aggregate emissions.Formula for achieving a 7.6-million-ton reduc-tion: Each State reduces total 1980 S02 emissionsby 35 percent.Cost: This approach is estimated to cost $2.6 to$3.1 billion annually, at an average cost of $385to $465/ton of S02 removed.Distributional consequences: This allocation for-mula requires an equal percentage reduction ineach State regardless of relative costs of emissionscontrol or stringency of the State’s existing emis-sions regulations. Those States: 1) with the high-est proportion of emissions from sources that aredifficult to control (e. g., certain industrial proc-esses and small residential, commercial, or indus-trial boilers), and 2) that have relatively low S02

emission rates, would incur the highest per-toncosts. This includes such States as Louisiana,Maine, Rhode Island, and Virginia.Total emissions per land area.Description: This approach is based on emissionsdensities, i.e., the amount of SO2 emitted per unitof land area. Emissions densities are calculatedfrom an area’s total emissions, rather than justits utility emissions.Rationale: To the extent that acid deposition isproduced by local sources, limiting the densityof SO2 emissions would help to limit the amountof sulfur deposited in the surrounding area.Formula for achieving an 8-million-ton reduction:Reductions are allocated by setting a maximumaverage emissions density of 16 tons of S02 persquare mile.Cost: This approach would cost $3.7 to $3.9 bil-lion per year, at an average cost of $560 to $585/ton of S02 removed.Distributional consequences: The States with thehighest emissions densities, and thus the largestproportional reductions and costs under this ap-proach, are Delaware, D. C., Indiana, Massachu-setts, Ohio, Pennsylvania, and West Virginia.

8. Total emissions per person.Description: Emissions reductions are calculatedon the basis of the amount of pollution emittedper person residing in the State. Reductions arebased on the region’s total emissions, not justutility emissions.Rationale: Giving credit to States with loweremissions-to-population ratios takes into accounta wide range of factors, including reliance onclean fossil fuel combustion, non-SO2-emittingelectricity generation, higher energy efficiency,and presence of fewer SO2-producing industrialactivities.Formula for achieving an 8-million-ton reduction:Reductions are allocated according to an aver-age rate of 200 lb of S02 per capita.Cost: The costs of this approach are estimated torange from $2.6 to $3.0 billion annually, with anaverage cost of $370 to $415/ton of S02 reduced.Distributional consequences: Those States witha relatively high proportion of total S02 emissionsto the population supported by emissions-gener-ating activities (both industrial and electricitygeneration) are allocated the largest reductions.These States include Indiana, Kentucky, Missou-ri, Ohio, Tennessee, and West Virginia.

Comparison of Utility Estimates of EmissionsReductions Costs to Various Regional-ModelEstimates

The Edison Electric Institute (EEI) requested itsmember utilities to estimate the cost of implementinga control proposal reported by the Senate Committeeon Environment and Public Works during the 97thCongress (S.3041, reintroduced as S.768 during the 98thCongress). The acid rain control sections of this billwould require eliminating about 9 million to 10.5 mil-lion tons of S02 per year in the Eastern 3 l-State re-gion—8 million tons per year allocated to States basedon utility S 02 emission rates and an additional 1 mil-lion to 2.5 million tons per year to offset expected emis-sions growth by 1995. * (S. 768 was subsequentlyamended to require an additional 2-million-ton emis-sions reduction. )

● The amount by which a State rnust reduce its SO2 emission was deter-mined by the following formula Calculate the difference between a State’s 1980utility emissions and the emissions that would result if no electric-generatingplant m that State emitted SO2 at a rate greater than 1.5 lb/MMBtu. Repeatthis calculation for the Eastern 31 -State region as a whole. The State propor-tion of the total regional difference, multiplied by 8 million tons, is the amountof SO2 emissions that must be eliminated m that particular State Any addi-tonal growth in emissions due to new facilities or increased use of existing onesby 1995 must also be offset


Twenty-four utilities responded, accounting for about3.5 million tons (about 45 percent) of the 8-million-tonreduction specified by the bill.42 Table A-14 comparesthese cost estimates to regional model-based estimatesprepared for EPA43 and OTA. * In general, the utilitiesprojected higher costs than the model-based statewideaverages. The OTA estimates are typically higher thanthe EPA estimates. There are several reasons for thesedifferences. First, some of the utilities surveyed havehigher S02 emissions rates than the statewide average.As a result, these utilities will have higher emissions re-duction costs than the statewide averages estimated bythe models.

Second, EEI, EPA, and OTA used different account-ing procedures. One major difference is the number ofyears over which capital costs are averaged. The EEIestimates reported in table A-14 are averaged (’‘lev-elized’ over 5 years;* both EPA and OTA average cap-ital costs over time periods equivalent to the life of thefacility (about 20 years). The shorter averaging timemakes the utility estimates of annual costs somewhathigher.

The estimates also make different assumptions aboutscrubber costs, low-sulfur coal prices, and the choice ofcontrol method. Some utilities project scrubber capitalcosts about equal to the average costs assumed by themodels (about $150 to $250 per kilowatt of generatingcapacity); however, several estimate costs almost twiceas high. EEI assumes that most of the emissions reduc-tion would occur through scrubbing, whereas the modelused by EPA projects that most emissions reductionswould be achieved by fuel-switching at a considerablecost savings over scrubbing. The OTA model calculatesa fairly even mix of scrubbing and fuel-switching toachieve the required emissions reductions, with coststypically between the EPA and utility estimates.

Overview of Model Usedin Cost Analyses

OTA’s cost estimates are based on a computer modelthat calculates the cost of reducing emissions at eachmajor utility generating unit in the 31 -State region

+ZNat iona] F;( ononl ic Research Assoclatcs, Inc , L‘.4 Report on the Results

From the Edison Electric Institute Study of the Impacts of the Senate Com-mittee on En\,ironment and Public Works Bill on A( Id Rain I,egislatlon(S.768), 1983.

‘lICF, Inc , “Analysls of a Senate Emission Re[iuctinn Bill” (S 3041) Pre-pared for EPA, 1983

● OTA’S cost estimates are from the AIRCOST model, E. H Pechan & As-soc iates, These estimates include the costs of emissions reductions required tooffset future cmlssrons growth, based on projections prepared for the Unite(iStates-Canada Memorandum of Intent, the Edison Electric Institute, and EPA

● EEI alsu reports utdity estimates of rate Increases based on first-year revt, -nue requirements; though typic all) about 25 percent higher than the 5-yearaverages, these are not representative of average costs for the Irfe of the program

(about 2,000 units in about 900 powerplants). For eachunit, the model determines the combination of emissionsreduction measures that minimizes the costs of comply-ing with a series of alternative emissions rate limitations,ranging from SIP compliance to a 0.4 lb SO2/MMBtulimit. Emissions reduction opportunities are then rankedon the basis of costs per ton of S02 removed. For eachalternative rate limitation, the model considers the costsof the following control options for each unit:

For coal-fired powerplant emissions:●

●

●

●

●

blending presently used coals with low-sulfur coals,switching to low-sulfur coals,physical coal cleaning to reduce the sulfur contentsof presently used coals,installing dry scrubbers in conjunction with eithercurrent or alternative coal types, andinstalling wet scrubbers in conjunction with eithercurrent or alternative coal types.

For plants burning residual oil:. switching to a lower sulfur oil.These results are in turn used to generate State and

regional cost estimates of various emissions reductionmeasures. These costs can be calculated in two ways:

1. State Least Cost: Reduction opportunities are se-

9

lected in ascending order of per-ton costs withineach State until the reduction target is achieved.Trading of emissions reductions among sources isallowed within States, but not among States. Thisapproach assumes a ‘‘perfect market for theexchange of emissions reductions obligationsthroughout the State and provides a lower boundmodel estimate.Plant Cap: Each plant is required to comply witha specified emissions limit. This approach to esti-mating costs chooses the least-cost approach ateach plant, but assumes no trading of reductionobligations among plants or States.

The cost model considers only S02 emissions fromutilities. No estimates of the cost of reducing emissionsof NOX, nor estimates for controlling S02 or NOx fromthe industrial sector, are calculated. Furthermore, ex-isting utilities are the only sources considered, and areassumed to be operating at their current level of capacityutilization. The OTA analysis assumes that all reduc-tions occur immediately, without accounting for newplants being built, or old plants being retired. Finally,the model does not include the following possible con-trol alternatives:

1. early retirement of major sources,2. energy conservation,3. selective use of lower emitting plants, and4. advanced control technologies.In calculating cost increases, OTA’s model assumes

that each plant chooses the most cost-effective methodof reducing emissions. However, State regulatory poli-

,


Table A-14.—Comparison of Estimates of Residential Electricity Rate Increases(8-million-ton SO2 reduction program, plus offsets for future growth)

1. Utilities located in single StatesFlorida: . . . . . . . . . . . .

Illinois: . . . . . . . . . . . .

Indiana: . . . . . . . . . . .

Massachusetts:. . . . .

Michigan: . . . . . . . . . .

Missouri: . . . . . . . . . .

North Carolina: . . . . .

Ohio: . . . . . . . . . . . . . .

Pennsylvania: . . . . . .

Wisconsin: . . . . . . . . .

Florida Power & Light Co.Tampa Electric Co.Statewide averagesIllinois Power Co.Central Illinois P.S.Statewide averagesPublic Service IndianaIndianapolis P. & L.Statewide averagesNew England Power Co.Statewide averagesDetroit EdisonStatewide averagesUnion Electric Co.Statewide averagesDuke Power Co.Statewide averagesCincinnati G. & E.Statewide averagesPennsylvania ElectricPennsylvania P. & L.Statewide averagesWisconsin Power & LightWisconsin Electric PowerStatewide averages

Il. Multi-State utilities:Florida, Georgia, Mississippi:

The Southern CompanyStatewide averages:

FLGAMS

Virginia, West VirginiaVEPCOStatewide averages:

VAWV

Indiana, Kentucky, Michigan, OhioAmerican Electric Power (AEP)Statewide averages:

INKYMlOH

EPA: 2-30/o, OTA:

EPA: 1-2°/0, OTA:

EPA: 7-80/o, OTA:

EPA: 1% OTA:

EPA: 2-40/o, OTA:

EPA: 5-7°/0, OTA:

EPA: 1-2°/0, OTA:

EPA: 6-70/o, OTA:

EPA: 3-5°/0, OTA:

EPA: 5-60/o, OTA:

12 ”/0EPA

2-30/o4-5 ”/0

3%

60/0EPA

1-20/05-60/o

180/0 (6-38 °/o)b

EPA7-80/o4-60/o2-40/o6 - 7 %

5%230/o

3-7 ”/018°/ob

21 “/02-11 “/0

250/o26°/ob

8-130/o4%

0-50/012 ”/0

2-60/o180/0

8-21 0/0

4%2-50/o

14 ”/08-120/o

200/0100/0

30/011 .30/012.30/o

1 1-120/0

OTA3-70/0

9-120/o5-200/o

OTA2-70/o

10-13 ”/0

OTA8-130/o

5-90/02-60/o

8-120/o,. —aEstimates are for a control program requiring SO2 emissions reductions in the Eastern 31-State region such that 1995 emis-sions are 8 million tons below 1980 levels. Emission limits for each State are allocated by a 1.5 lb SO2/MMBtu emission rateIimitation for utilities. Including reductions to offset future growth, about 9 to 10.5 million tons of SO2 per year must be eliminatedfrom existing sources

bFor these utilities, about one.third to one-half of capital costs are for new utility construction to replace Prematurely retiredplants, or to compensate for electricity losses due to scrubbers

SOURCE Compiled by Off Ice of Technology Assessment See text for references.


cies can affect this choice— and hence the costs—in waysnot treated by the model. For example, in most States,‘‘automatic fuel adjustment clauses’ allow utilities topass on increased fuel costs due to fuel-switching to con-sumers within a few months. However, for emissionscontrols requiring capital investment, such as scrubbers,most States require utilities to wait until the equipmentbecomes operational before charging ratepayers. Thispractice may create a bias against capital investment in

pollution control equipment in utility management deci-sionmaking, and increase a plant’s lifetime control costs.

The model used by OTA also assigns all control coststo the State whose utility owns the facilities required toreduce emissions. The accuracy of this assumption de-pends on the policy chosen for allocating costs. To re-lieve utilities or States that are allocated particularlylarge emissions reductions, costs could be shared by elec-tricity consumers in other areas.

A.4 ALTERNATIVE TAX STRATEGIES TO HELPFUND ACID RAIN CONTROL

Several acid rain control bills introduced during the98th Congress proposed establishing a trust fund to helpfinance the costs of emissions reductions for controllingacid deposition. The proposals were based on one of twoalternative approaches for raising revenues: a tax on pol-lutant emissions, or a tax on electricity generation. Eachof these approaches could be implemented in severalways.

This section considers two alternative pollution taxes:1) a tax on both sulfur dioxide (S02) and nitrogen ox-ides (NOX), and 2) a tax on S02 emissions only. Bothapply to nationwide pollutant emissions. The sectionanalyzes the distribution of the two taxes by emissionssource, and the electricity portion of the tax by State,and compares them to two electricity-based ap-proaches: 1) a tax on total electricity generation, and2) a tax on nonnuclear electricity generation.

All four tax schemes are possible alternatives to re-quiring those sources that must reduce emissions to paythe entire costs of control. Funds raised by a tax canbe used to pay part or all control costs. A pollution taxwould apportion control costs to a larger group of emit-ters, not just those required to reduce emissions. How-ever, because so few sources are actually monitored,such an approach would be administratively complex.An electricity tax would also distribute control costs toa larger group of emitters, but is not directly related toactual emissions. However, because electricity genera-tion is carefully monitored, this approach would bemuch easier to implement.

The analyses presented below are approximate, in-tended to illustrate the relative distribution of costs forraising an arbitrary $5 billion per year under each ap-proach. The actual amount of the tax, and to some ex-tent the distribution of the tax, varies with each spe-cific control plan and trust-fund design.

Distribution of Emissions, Tax Rates,and Tax Revenues by Source

About 90 to 95 percent of the Nation’s manmade S02

emissions originate from utility and industrial sources.About 95 percent of the Nation’s manmade NO, emis-sions originate from utility, industrial, and transporta-tion sources. Emissions from these sectors can be con-sidered the potentially ‘ ‘taxable’ pollutant inventory

(though in practice assessing emissions from all sourcesin each category with sufficient accuracy for tax pur-poses would be difficult). Emissions from residential,commercial, and other small dispersed sources are notconsidered taxable for this analysis.

For example, to raise $5 billion per year, by deriv-ing two-thirds of the revenues from S02 and one-thirdfrom NOX emissions, * the tax must be set at about$135/ton of S02 and $85/ton of NOX emitted. A tax onS 02 emissions alone must be set at about $200/ton.These rates are based on 1980 taxable emissions; rev-enues from a fixed tax rate would increase as emissionsincrease, and would decrease if acid rain control legis-lation were enacted. To raise $5 billion per year throughtaxes on electricity generation, the following rates mustbe set: 2.2 mills/kWh for all electricity generated and2.5 mills/kWh for nonnuclear electricity only. Total rev-enues in future years would follow changes in electri-city demand.

Table A-15 displays each sector’s contribution to anacid rain control trust fund based on the above rates.The two-pollutants tax (i. e., on both SO2 and NOx)would raise about $2.8 billion (55 percent) from utili-ties, about $1.4 billion (30 percent) from industry, and

● About twice as much precipitation acidity currently originates from sulfurcompounds as from nitrogen compounds in the Eastern United States.


Table A-15.—Annual Contribution to Acid Rain Control Trust Fund From AlternativeTax Approaches (billions of dollars/yr, see text for explanation of alternative taxes)

Emissions tax Emissions tax(before control- (after control-1980 emissions) 1995 emissions) Electricity tax

SO2 & SO2 SO2 & s o * Total NonnuclearNOx only NOX only electricity electricity

Electric utilities. . . . . . . . . . . 2.8 3.5 1.8 1.6 5.0 5.0Industry . . . . . . . . . . . . . . . . . 1.4 1.5 1.6 1.8 0.0 0.0Transportation . . . . . . . . . . . 0.8 0.9 0.9 0.0 0.0 0.0

Total United States. . . . . . 5.O 5.0 4.3 3.4 5.0 5.0

SOURCE: Office of Technology Assessment, based on data from Emissions, Costs and Engineering, Work Group 3B, UnitedStates-Canada Memorandum of Intent on Transboundary Air Pollution, June, 1982 and the Statistical Year Book ofthe Electric Utility Industry, Edison Electric Institute, 1980

$0.8 billion (15 percent) from transportation sources.If only SO 2 were taxed, about 70 percent of the fundwould come from utilities and about 30 percent fromindustry.

The third and fourth columns in table A-15 estimatetax revenues in 1995 after a hypothetical acid rain con-trol program, assuming that the tax rates remain un-changed. Utility S02 emissions in the Eastern 31 Statesare assumed to be 10 million tons below 1980 levels.All other emissions are assumed to grow at rates calcu-lated from emissions projections developed under theUnited States-Canada Memorandum of Intent onTransboundary Air Pollution. The share of annual trustfund revenues derived from utilities would decline toabout 40 percent of the total for the two-pollutants tax,and to about 45 percent of the total for the SO2 tax. Be-cause total nationwide pollutant emissions decline, thetotal tax collected drops by 15 and 30 percent, respec-tively.

A tax on electricity generation (either total or non-nuclear) is assumed to come entirely from the utility sec-tor (i. e., industrial generation of electricity for internaluse is not taxed).

Geographic Distribution ofElectricity Rate Increases

Table A-16 presents State-by-State costs of the alter-nate tax approaches for the electric utility sector only.Costs to industry are often borne by consumers froma much larger area than the State in which the industryis located, since many manufactured goods are distrib-uted nationwide. A tax on mobile source emissions (e. g.,a sales or registration tax) would be distributed on aroughly per-capita basis.

The large variation in current pollution emission ratesamong utility plants would cause a pollution tax to dis-tribute costs unevenly both within a State and from State

to State. As shown in table A-16, though a pollutiontax to raise $5 billion per year would increase averageresidential electricity rates by about 2 percent, State-average increases would range from virtually no increaseto about 9 percent. Because utilities emit a larger shareof nationwide S02 than NOx emissions, electricity rateincreases are typically somewhat lower for a tax on bothS02 and NOX emissions (co1. 1) than on S02 emissionsonly (co1. 2).

Assuming that emissions reductions are achieved, *Eastern States would experience smaller rate increasesdue to the pollution tax in 1995 (COlS. 3 and 4) than in1980. Western-State rate increases would be higher in1995 than in 1980 due to projected increased emissions.The tax rate is assumed to be indexed to inflation,so that rate changes shown in 1995 are due solely toemissions changes and not to changes in the price of elec-tricity.

The last two columns of table A-16 estimate residen-tial rate increases from a fixed kilowatt-hour tax onall electricity, and on nonnuclear electricity, generatedin each State. State-to-State variations are due solelyto differences in the average electricity rate currentlypaid by consumers in each State. Large percentage in-creases imply low current rates for electricity. Nation-wide, the rate increases from a tax on electricity genera-tion are greater than for a pollution tax under whicha significant share of the total $5 billion per year taxcomes from other sectors. However, in several Midwest-ern States (e. g., Indiana, Kentucky, Missouri, andOhio) with high rates of pollutant emissions, an electri-city tax would be less costly than an emissions tax dur-ing the years before emissions reductions are achieved.


Table A-16.—5O.State Taxes Raising $5 Billion per Year During the Early 1980’s

Average residential electricity rate increase (percent) from alternative tax approaches

Emissions tax Emissions tax(before control- (after control-1980 emissions) 1995 emissions) Electricity tax

S 02 & s o * so* & SO2 Total Nonnuclear

2.00.90.70.60.21.30.31.42.21.73.50.80.02.95.93.01.85.70.50.41.81.62.51.82.16.60.91.31.02.90.8

0.71.81.94.50.60.12.71.31.41.15.30.70.80.11.20.54.14.1

NOx only NOX ony~ electricity electricity

Alabama . . . . . . . . . . . . . . .Alaska . . . . . . . . . . . . . . . . .Arizona . . . . . . . . . . . . . . . .Arkansas. . . . . . . . . . . . . . .California . . . . . . . . . . . . . .Colorado . . . . . . . . . . . . . . .Connecticut . . . . . . . . . . . .Delaware . . . . . . . . . . . . . . .District of Columbia. . . . . .Florida. . . . . . . . . . . . . . . . .Georgia . . . . . . . . . . . . . . . .Hawaii . . . . . . . . . . . . . . . . .Idaho . . . . . . . . . . . . . . . . . .Illinois . . . . . . . . . . . . . . . . .Indiana . . . . . . . . . . . . . . . .lowa . . . . . . . . . . . . . . . . . . .Kansas . . . . . . . . . . . . . . . .Kentucky. . . . . . . . . . . . . . .Louisiana . . . . . . . . . . . . . .Maine. . . . . . . . . . . . . . . . . .Maryland . . . . . . . . . . . . . . .Massachusetts. . . . . . . . . .Michigan . . . . . . . . . . . . . . .Minnesota. . . . . . . . . . . . . .Mississippi . . . . . . . . . . . . .Missouri . . . . . . . . . . . . . . .Montana . . . . . . . . . . . . . . .Nebraska . . . . . . . . . . . . . . .Nevada . . . . . . . . . . . . . . . .New Hampshire . . . . . . . . .NewJersey . . . . . . . . . . . . .New Mexico . . . . . . . . . . . .NewYork . . . . . . . . . . . . . . .North Carolina . . . . . . . . . .North Dakota . . . . . . . . . . .Ohio . . . . . . . . . . . . . . . . . . .Oklahoma . . . . . . . . . . . . . .Oregon . . . . . . . . . . . . . . . .Pennsylvania . . . . . . . . . . .Rhode Island . . . . . . . . . . .South Carolina . . . . . . . . . .South Dakota . . . . . . . . . . .Tennessee . . . . . . . . . . . . .Texas . . . . . . . . . . . . . . . . . .Utah . . . . . . . . . . . . . . . . . . .Vermont . . . . . . . . . . . . . . .Virginia . . . . . . . . . . . . . . . .Washington . . . . . . . . . . . .West Virginia . . . . . . . . . . .Wisconsin . . . . . . . . . . . . . .

SOURCE: Based on data from Emissions, Costs and Engineering, Work Group 3B, United States-Canada Memorandum of lntent,June 1982; and the Statistical Year Book of the Electric Utility Industry, Edison Electric Institute, 1980,

2.51.40.70.50.21.20.31.82.72.24.51.10.03.6

3.52.07.30.20.62.32.13.02.0

8.80.91.30.93.60.90.90.92.12.05.90.30.13.51.51.71.17.00.50.60.01.40.75.15.2

1.31.2

0.50.31.70.31.02.31.21.81.10.01.52.31.92.42.60.60.41.11.11.91.6

2.31.31.71.41.60.7

0.41.72.51.90.90.11.51.51.01.4

0.91.10.11.10.72.31.9

1.21.80.90.30.21.50.31.02.71.21.71.40.01.21.81.62.62.20.20.61.21.31.71.31.11.91.11.71.11.40.6

0.51.72.61.60.50.11.51.50.91.42.00.70.80.01.20.92.01.5

4.04.03.14.43.03.72.52.44.53.14.21.88.23.63.83.63.74.5

3.33.62.94.33.84.04.16.44.73.92.92.62.92.13.74.13.34.5

3.13.03.63.64.93.73.63.53.39.54.24.4

3.14.43.53.03.34.01.52.75.02.94.12.09.22.9

3.64.15.04.71.62.62.93.82.94.54.67.23.44.43.32.1

2.03.94.63.65.06.93.23.32.44.15.54.1

0.92.5

10.5

3.6


A.5 OTHER EMISSION SECTORS

This section addresses major nonutility sources of S02

and NOX emissions. It presents estimates of currentemissions, potential emissions reductions, and controlcosts, where possible, for: 1 ) industrial and large com-mercial boilers, 2) industrial process emitters (e, g.,smelters and petroleum refineries), and 3) mobilesources. Together, these source categories account forapproximately 30 to 35 percent of S02 and 65 to 70 per-cent of NOx. emissions in the continental United States.

In general, data needed to estimate emissions fromthese sources are scanty and of questionable accuracy.In addition, emissions control methods, particularly forindustrial processes, are in earlier stages of developmentthan for utilities. Consequently, the estimates of emis-sions, potential emissions reductions, and estimated con-trol costs presented in this section are subject to greateruncertainty than those presented earlier for the utilitysector.

Industrial and Commercial Boilers

Industrial and large-commercial boilers emitted about3.5 million tons of SO2 in 1980; table A-17 provridesState-by-State emissions estimates for these sources.Two estimates are presented; one is calculated fromState-levcl fuel deliveries, the other from data reportedto EPA .44 Though the national totals are quite close,the difference at the State-levrel is often quite large.Largest emitting States were New York (about 350,000to 450,000 tons), Ohio (about 300,000 to 400,000 tons),and Pennsylvania (about 250,000 to 300,000 tons); nineadditional States had nonutility boiler emissions greaterthan about 100,000 tons of S02 per year.

Table A-17 also indicates the percentage of this sec-tor’s 1980 emissions that would have to be eliminatcdunder various emission rate limitations. In comparisonto the utility sector, S02 emission rates from industrialand commercial boilers are relatively low. Thus, con-trol strategies based on emission rate limitations wouldreduce emissions from this sector by a smaller propor-tion than comparable controls on the utility sector. Forexample, an emission rate limitation of 1.5 lb of S02

per million Btu would eliminate slightly over a quarterof this sector’s 1980 emissions (slightly under 1 milliontons of’ S02 annually); an identical cap on utility emis-sions would eliminate slightly less than half of that sec-tor’s SO2 emissions (about 8 million tons of SO2 an-nually).

The lower S02 emission rates from nonutility boilersare due to the lower sulfur content of the fuels burned.A 1979 Department of Energy (DOE) survey45 foundthat natural gas (which emits almost no S02) suppliedabout 32 percent of the energy requirements of indus-trial boilers. Coal and oil each accounted for about 17percent of boiler fuels (as compared to 58 and 12 per-cent, respectively, of fuels used by utilities). The re-mainder came from such fuels as wood, bark, coke ovengas, and paper-pulping liquor.

Many nonutility boilers are capable of burning a widevariety of fuel types. Thus, if emissions controls wererequired for nonutility boilers, reductions in S02 emis-sions could be met by substituting lower sulfur fuels oreven changing fuel types. Boilers currently burninghigh-sulfur oil might switch to low-sulfur oil. Naturalgas, which accounted for over 30 percent of commer-cial and industrial boiler fuel use in 1979, might alsobe substituted, Federal and State regulations permitting.

For boilers equipped to burn coal, available strategiesfor reducing emissions include switching to lower sulfurcoal, and cleaning exhaust gases with scrubbers. Switch-ing to low-sulfur oil or gas may be possible in manycases, but would probably not be as cost effective as low-sulfur coal. Table A-18 estimates per-ton costs associatedwith three fuel-switching and two scrubber-installationscenarios.

Industrial Processes *

Industrial processes are estimated to account for ap-proximately 15 to 20 percent of the SO2 emitted nation-wide and about 7 to 12 percent of those emitted in theEastern 31 -State region of the United States. Less than5 percent of U.S. NOX emissions came from industrialprocesses. Data on emission rates for individual sourcesare scanty. Moreover, relatively little literature is avail-able on the technical feasibility and costs of controllingemissions from these sources. Consequently, emissionsand control cost estimates are subject to greater uncer-tainty than those associated with utility, industrial, andcommercial boiler operations. A study produced forOTA by Energy & Resource Consultants, Inc., providespreliminary estimates of S02 emissions and control costsfor five major industrial sectors: 1) pulp and paper,

99 - 413 0 - 84 - I 3 ; g . ~

I&# . Acid Rain and Transported Air Pollutants: Implications for Public Policy

Table A-17.-Potential SO2 Reductions From Nonutility Boilers

Non utility boiler SO2 emissions Percent reduction in emissions with(thousand tons/yr) emission limit (lb/MMBtu)

State U.S./Canada a NEDSb 1.0 1.2 1.5 2.0 2.5Alabama. . . . . . . . . . . . . . . . . . . . . . . . . . . . .Arizona. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Arkansas . . . . . . . . . . . . . . . . . . . . . . . . . . . .California. . . . . . . . . . . . . . . . . . . . . . . . . . . .Colorado . . . . . . . . . . . . . . . . . . . . . . . . . . . .Connecticut . . . . . . . . . . . . . . . . . . . . . . . . .Delaware . . . . . . . . . . . . . . . . . . . . . . . . . . . .District of Columbia . . . . . . . . . . . . . . . . . .Florida . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Georgia . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Idaho . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Illinois . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Indiana . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .lowa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Kansas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Kentucky . . . . . . . . . . . . . . . . . . . . . . . . . . . .Louisiana . . . . . . . . . . . . . . . . . . . . . . . . . . . .Maine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Maryland . . . . . . . . . . . . . . . . . . . . . . . . . . . .Massachusetts . . . . . . . . . . . . . . . . . . . . . . .Michigan . . . . . . . . . . . . . . . . . . . . . . . . . . . .Minnesota . . . . . . . . . . . . . . . . . . . . . . . . . . .Mississippi . . . . . . . . . . . . . . . . . . . . . . . . . .Missouri . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Montana . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Nebraska . . . . . . . . . . . . . . . . . . . . . . . . . . . .Nevada . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .New Hampshire . . . . . . . . . . . . . . . . . . . . . .New Jersey . . . . . . . . . . . . . . . . . . . . . . . . . .New Mexico . . . . . . . . . . . . . . . . . . . . . . . . .New York. . . . . . . . . . . . . . . . . . . . . . . . . . . .North Carolina . . . . . . . . . . . . . . . . . . . . . . .North Dakota . . . . . . . . . . . . . . . . . . . . . . . .Ohio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Oklahoma . . . . . . . . . . . . . . . . . . . . . . . . . . .Oregon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Pennsylvania, . . . . . . . . . . . . . . . . . . . . . . . .Rhode Island . . . . . . . . . . . . . . . . . . . . . . . . .South Carolina . . . . . . . . . . . . . . . . . . . . . . .South Dakota . . . . . . . . . . . . . . . . . . . . . . . .Tennessee . . . . . . . . . . . . . . . . . . . . . . . . . . .Texas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Utah . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Vermont . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Virginia . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Washington . . . . . . . . . . . . . . . . . . . . . . . . . .West Virginia . . . . . . . . . . . . . . . . . . . . . . . .Wisconsin . . . . . . . . . . . . . . . . . . . . . . . . . . .Wyoming . . . . . . . . . . . . . . . . . . . . . . . . . . . .

National totals . . . . . . . . . . . . . . . . . . . . .

869

3256243426

974411

188290

57116676655658

15444485525

42

1074

2334116

13310

15

2548

843

83106

165

1424184

10730

3,491

11947

153191420149766

5111129

560

3278932333

122494617942

2078

9455130

5403

1314

3144

762

97121

162

1292894

15032

3,514

5132

01516

13

11485622455972

0521359

00

5047

04080341551

0581447327032

012

7451950

52739492457604537

4429

06

13124

414816405367

0461151

00

4338

03577291043

053

737

6627

011

0351344

31830401850553632

3527

03

10112

3138

8344559

041

38o0

3526

0287120

529

048

524

96120

0100

226

3717

17271341492426

2322

026101

1722

0263547

033

71900

26140

206511070

40374

53807080

27010

109

3138

718

15150151009

100

192835

027

6200

21

01560

6000

33214

46506010

2100017

2230

213

SOURCES: Office of Technology Assessment, based on: admissions, Costs and Engineering Assessment, Work Group 3B, United States-Canada Memorandum of intenton Transboundary Air Pollution, June 1982; and bEPA’s National Emissions Data System.


Table A-18.— Representative Costs for ReducingS02 Emissions From Coal-Fired Industrial Boilers

$/ton S02 removedIndustrial strategies (1982 dollars)

Shift from higha- to Iowb-sulfur coal . . $ 250-$550Shift from high- to mediumc-sulfur

coal. . . . . . . . . . . . . . . . . . . . . . . . . . . . 300-500Shift from medium- to low-sulfur

coal . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400-1,000Shift from unscrubbed high to

scrubbed high sulfur . . . . . . . . . . . . 800-1,000Shift from unscrubbed medium to

scrubbed medium sulfurd . . . . . . . . . 1,200-2,000aAbout 3 to 5 lb SO2/MMBtubAbout 1.5 to 25 lb SO2/MMBtuCAbout 0.8 to 1.3 lb SO2/MMBtudBased on the costs of retrofitting a scrubber on a 170 MMBtu/hr coal-fired in-

dustrial boilerSOURCE Analysis of Senate Emission Reduction Bill (S 3041) Report pre-

pared for EPA by ICF, Inc , 1983

2) cement, 3) sulfuric acid production, 4) iron and steel,and 5) nonferrous metal smelting. Emissions estimates(but not control costs) are also presented for petroleumrefining.

Table A-19 presents estimates of SO2 emissions fromthese six industries: 1 ) by EPA region for the 31 East-ern States, 2) for the remainder of the United States,and 3) for the Nation overall. In nearly all cases, S02emissions have been estimated indirectly, by applyingan emissions factor to estimated plant production orproduction capacities derived from industry surveys. Forthe cement and pulp and paper industries, in particu-lar, the wide variability in potential emissions per unitof production capacity leads to a range of emissions esti-mates. Estimates for the iron and steel industry arederived from actual output levels, and are presented foryears of differing iron and steel production, to illustratethe effects of production levels on emissions. Whereavailable, estimates of emissions calculated for otherstudies are also included to further demonstrate the sig-nificant uncertainties in these estimates.

Production processes for five of these industries wereexamined in some detail to determine how much S02

could feasibly be eliminated from their emissions, andat what cost. As presented in table A-20, rough estimatesshow that about 1 million tons of S02 could be elimi-nated from process emissions in the Eastern 31-Stateregion, at widely differing cost levels. Slightly more thanhalf these emissions—primarily from sulfuric acid plantsand coke ovens—could be eliminated at average costsof $500/ton or less; an additional 300,000 tons mightbe eliminated from cement plant emissions at an aver-age cost of approximately $ 1,000/ton. However, esti-mates of potential emissions reductions, and associatedcosts, for several of these industries are based on tech-

nologies that are theoretically feasible but not commer-cially proven. The computation methods used to derivecost estimates mask significant variations from plant toplant within each industry; only in the pulp and paperindustry was sufficient information available to presenta range of per-ton cost estimates, based on differencesin plant sizes, economies of scale, and differing produc-tion processes in use—the average per-ton cost of con-trol is estimated to be $2,600, ranging from $450 to$14,800/ton of S02 removed.

Only the cement industry, of the five surveyed, wasfound to emit substantial quantities of NOX—approximately 120,000 tons in the Eastern 31 -State re-gion, and 80,000 tons in the Western portion of theUnited States.

Mobile Sources *

Automobiles and other mobile sources produce sub-stantial amounts of two pollutants, NO, and hydrocar-bons (HC). NOx and HC are the primary pollutantsthat react in the atmosphere to form ozone and otheroxidants. NOx can also be converted to nitrates, acomponent of acid deposition.

Many recent studies suggest that ozone and ozoneprecursors (NOX and HC) are transported long dis-tances. The highest concentrations of ozone do not nec-essarily occur where emissions densities are greatest(i.e., in cities), but, because of chemical transformationsover time, at locations that are several hours downwind.

The extent to which mobile sources contribute to aciddeposition is uncertain. Tailpipe emissions may not dis-perse sufficiently to reach the mixing layer of the atmos-phere, where they are readily transported and trans-formed into acid compounds. However, mobile sourceshave been linked to increases in acid deposition in urbanareas, e.g. , the Los Angeles Basin.46

Current Emissions: Mobile sources account formajor portions of both NOx and HC emissions nation-wide, and a very small portion of S02 emissions. As of1978, mobile sources contributed 40 percent of nation-al NOx emissions (10.3 million tons), approximately 38percent of total HC emissions (1 1.8 million tons), and3 percent of national S02 emissions (0.9 million tons) .47

Of NOX emissions from mobile sources, approxi-mately 40 percent came from automobiles, 10 percent

● This subsection is based on M P Walsh, “Motor Vehicle Emissions of

Nitrogen Oxides, ” contractor report submitted to the Office of TechnologvAssessment, 1981

46PEDCo Environmental, Inc., , and Paul W. Spaite Co., Perspective on the

Issue of Acid Rain, DOE contract No DE-AC21-81 MC16361, June 1981+T,Narlon~ Air ~o)]u[anr Emission Estmafes, /970-J 978, offke of Alr @AltY’

Planning and Standards, U S Envmonrncntal Protec tmn Agwrcy, EPA-4.50/4-80-002, ,January 1980

Table A-19.—SO2 Emissions From Industrial Processes (estimates for 1980 in thousand tons/yr)

Iron and steel

Sul fur ic a b Cokea Petroleum b Copper a

EPA region Pulp and paperac Cementa acid ovens only T o t a la b refineries smelting

1 . . . . . . . . . . . . . . . . . . 7 (3-15) 3 (2-4) 1 4 — o 0II . . . . . . . . . . . . . . . . . 7 (3-17) 36 (24-52) 8-22 7 20 42 0Ill . . . . . . . . . . . . . . . . . 10 (4-22) 84 (57-130) 12-22 66 165 79 0Iv. . . . . . . . . . . . . . . . . 63 (23-140) 96 (58-120) 130-270 15 36 29 7v . . . . . . . . . . . . . . . . . 6 (3-15) 110 (75-160) 16-37 68 180 170 72VI (partial). . . . . . . . . . 18 (7-40) 13 (8-18) 39-83 0 0 105 0Vll (partial) . . . . . . . . . 1 (l-4) 63 (43-95) 5-11 1 1 8 0Eastern 31-States . . . 110 (43-250) 410 (270-580) 210-450 160 250-400 430 79West . . . . . . . . . . . . . . 26 (1 7-57) 240 (150-310)United States total . .

53-160 16 23-26 565 1,380150 (66-340) 650 (410-890) 263-610 180 280-400 1,000 1,460

NOTE Summed estimates have slight discrepancies from combining several sources of data.

SOURCESaEnergy and Resource Consultants, Inc., “Background Documentation SOX and NOX Emissions From Five Industrial Process Categories, ” OTA contractor report, 1982bWork Group 3B, “Emissions, costs and Engineering Assessment “ Report prepared under the Memorandum of Intent on Transboundary Air Pollution signed by the

United States and Canada, 1982.CMitre Corp. estimates published in "Background Document on Sox and Nox Emissions From Five Industrial Process categories. ”

States within EPA regions: l—Maine, Vermont, Massachusetts, New Hampshire, Connecticut, Rhode Island; n-New York, New Jersey; 111—Pennsylvania, Maryland, Dela-ware, West Virginia; IV—Florida, Kentucky, Tennessee, North Carolina, South Carolina, Mississippi, Alabama, Georgia; V—Minnesota, Wisconsin, Indiana, Ohio, Michigan;Vi—Arkansas, Louisiana, VIl —lowa, Missouri.


Table A-20.—Potential S02 Emissions Reductions andfor Industrial Processes

——Pulp

a n d S u l f u r i c C o k ea

p a p e r C e m e n t ac id o v e n s

Control Costs

Other irona C o p p e rb

and steel smelting

Total United StatesC u r r e n t e m i s s i o n s

(10 3 tons) ... . . . . . . . . . . . . . . 1 5 0 6 5 0 6 1 0 2 3 0 120 1,460P o t e n t i a l e m i s s i o n s r e d u c t i o n s

(10 3 tons) . . . . . . . . . . . . . . . . 1 3 0 ’ 5 2 0d 5 1 0 ’ 185’ 2 7g

3 5 0h

Eastern 31 StatesPotential emissions reductions

(10 3 tons) . . . . . . . . . . . . . . . . . . 110 330 360 170 24 0

$/ton . . . . . . . . . . . . . . . . . . . . . . . . 2,600I 1,000 550 300 >3,000 —

WestPotential emissions reductions

(10 3tons) . . . . . . . . . . . . . . . . . . . 20 190 150 15 3 350$/ton . . . . . . . . . . . . . . . . . . . . . . . . 2,600i 1,000 500 300 >3,000 200

aEmissions estimates for the Iron and steel industry are based on 1976 production levels rather than 1980 levels due to I hedepressed production rates in 1980bEmmissions estimates for copper smelting assume that all smelters still operational are producing at near-full capacity‘Assumes that exhaust gases from recovery boilers are scrubbed with a removal efficiency of 85 percentdAssumes that wet scrubbers are installed on cement kilns, with an 80. percent removal efficiency This is not a Commerciallyproven technology.eAssumes sodium sulfite scrubbing to achieve a 3 lb/ton of acid emissions limit.fAssumes coke oven gas desulfurization with 90 -percent removal efficiencygAssumes that wet scrubbers are installed on sinter plants with a 90-percent removal efficiencyhBased on the use of double contact acid plants at the Phelps-Dodge Ajo and Douglas smelters in ArizonaI Estimates range from $450 to $14 800/ton

SOURCE Energy and Resource Consultants, Inc , OTA contractor report, 1982.)

from light-duty trucks, 25 percent from heavy-dutytrucks, and 25 percent from other mobile sources suchas trains and off-highway vehicles. Of HC emissions,60 percent came from automobiles, somewhat greaterthan 10 percent each for light- and heavy-duty trucks,and 15 percent from other mobile sources. State-levelestimates of NOX emissions from mobile sources areshown in table A-2; NOX emissions from highway ve-hicles alone—about 7.5 percent of total mobile sourceemissions—are presented in table A-21.

Trends in Highway VehicleEmissions

Since 1940, nationwide NOX emissions have approx-imately tripled; a fourfold increase in the number ofmotor vehicles since 1945 contributed significantly tothis dramatic growth rate .48 In addition, NOX emis-sions per mile driven increased during the late 1960’sand early 1970’s, due to the technologies used to im-plement the first generation of HC and carbon monox-ide (CO) emissions control standards. Between 1970 and1978, HC emissions from highway vehicles decreased

by about 10 percent, from 11.3 million to 10.2 milliontons, while NOX emissions increased by 25 percent,from 5.8 million to 7.4 million tons.49

During the same period, vehicle miles traveled in theUnited States increased by about 37 percent, showingsome decline in NOX emission rates due to controlsmandated by the Clean Air Act. Since the late 1970 ‘s,overall amounts of NOX emissions from motor vehiclcshave also begun to decrease slight]?’ as the proportionof NOX-controlled vehicles in the United States in-creases.

To estimate future NOX emissions levels for highwayvehicles, OTA has projected three alternative travel sce-narios for 1995: a no-growth, a low-growth, and a me-dium-growth case. Estimates of \’chicle-miles traveledunder the three scenarios were then used to project na-tionwide 1995 NOX emissions from highway vehiclcsunder a variety of control standards. Table A-22 sum-marizes the effects of the various growth cases and emis-sions standards on 1995 NOX emissions projections.

Two cases have been selected from among the 18 pro-jected emissions levels to represent a likely lower and

upper bound for emissions estimates. The lower-bound


Table A-21 .—1980 U.S. NOX EmissionsFrom Highway Vehicles (103 tons)

Eastern region Western region

State NOX State NOx

Alabama . . . . . . . . 127 Alaska. . . . . . . . . . 13Arkansas. . . . . . . . 74 Arizona . . . . . . . . . 87Connecticut . . . . . 87 California . . . . . . . 696Delaware. . . . . . . . 20 Colorado. . . . . . . . 87District of Hawaii . . . . . . . . . . 20

Columbia . . . . . 13 Idaho . . . . . . . . . . . 33Florida . . . . . . . . . 328 Kansas . . . . . . . . . 74Georgia. . . . . . . . . 194 Montana . . . . . . . . 27Illinois . . . . . . . . . . 281 Nebraska . . . . . . . 54Indiana . . . . . . . . . 174 Nevada . . . . . . . . . 27lowa . . . . . . . . . . . 80 New Mexico. . . . . 47Kentucky . . . . . . . 120 Oklahoma . . . . . . . 120Louisiana . . . . . . . 100 Oregon . . . . . . . . . 80Maine . . . . . . . . . . 33 South Dakota. . . . 27Maryland. . . . . . . . 13 Texas . . . . . . . . . . 482Massachusetts . . 154 Utah. . . . . . . . . . . . 40Michigan. . . . . . . . 281 Wyoming . . . . . . . 20Minnesota . . . . . . 120Mississippi . . . . . . 74Missouri . . . . . . . . 154New Hampshire . 27New Jersey . . . . . 221New York . . . . . . . 341North Carolina. . . 187Ohio . . . . . . . . . . . 321Pennsylvania . . . . 308Rhode Island . . . . 27South Carolina . . 107Tennessee . . . . . . 147Vermont . . . . . . . . 13Virginia . . . . . . . . . 127West Virginia. . . . 54Wisconsin . . . . . . 147

31 + D.C. total . . 4,454 West total . . . . . .1,934 0U.S. total . ......6,388

SOURCE: Michael P Walsh, “Motor Vehicle Emissions of Nitrogen Oxides,” OTAcontractor report, Nov. 30, 1981.

Table A-22.—1995 Highway Vehicle NOX Emission Projections

Emissions standards 1995 nationwide emissions (1,000 tons)Auto a Light trucka Heavy truckb No growth L O W g o w t h c Medium growthd

1.0 1.2 1.7 3,067 3,759 4,7671.0 1.2 4.0 3,633 4,608 5,7251.0 1.2 6.0 4,104 5,287a 6,4871.5 1.7 6.0 4,764 6,052 7,5142.0 2.3 10.7 5,868 7,469 9,193b

None None None 7,950 9,880 12,438%Grams/mile.bGrams/brake horsepower-hour.CLOW growth:

Autos and light trucks grow 1% per year.Heavy gasoline trucks decline 2% per year,Heavy diesel trucks grow 4% per year.

‘Medium growth:Autos and Iight trucks grow 3% per year.Heavy gasoline trucks decline 2% per year.Heavy diesel trucks grow 5% per year.

SOURCE: Michael P. Walsh, “Motor Vehicle Emissions of Nitrogen Oxides,” OTA contractor report, Nov. 30, 1981.


scenario assumes low growth, retention of the 1.0 gramper mile (gpm) automobile standard currently in effectfor 1981 and later model cars, and a tightening of light-and heavy-duty truck standards to 1.2 gpm and 6.0grams per brake horsepower-hour respectively, as the1977 Clean Air Act Amendments require. By 1995, thiswould result in a 21 -percent reduction from currentNOX mobile-source emissions.

The upper-bound scenario assumes medium growth,retention of the current light- and heavy-truck stand-ards rather than any tightening, and a rollback of theautomobile standard to 2.0 gpm. This would result ina 37-percent increase in NOX mobile-source emissionsover 1980. Assuming a low-growth scenario with thesesame emissions standards would result in only a 12-per-cent NOX increase over 1980 levels.

costs

Estimatesof emissions

of Automobile EmissionsControls

of the costs and fuel-economy implicationscontrols are highly controversial. The Bu-

reau of Labor Statistics has estimated that between 1975and 1979, pollution control devices have increased thecost of new automobiles by about $ 165—approximately10 percent of the total cost increase for new cars duringthe same 5 years. EPA and manufacturers’ estimatesof the costs50 of meeting statutory automobile emissionstandards of 0.4 gpm HC, 3.4 gpm CO, and 1.0 gpm

‘“( “I’he (;OSI of ~;(jn[rnlllng F.mlsslorss n f 1981 Model Year Autnmobilm,u S F,nt.lrorlrIlen~a] Pr~)tt.{ IIon A~nc y, .Junc 1981, t es t imony bv M i c h a e l

k$’alsh before the iiea]tb and Errvlronrnent Subcomml(tee, U S House of Rcp-rcsen[atl\e\, Sept. 21, 1 981, an[i letter from Betsy Ancker-Johnson, GeneralNlotori t{) I) OUql<L\ (jostle, u s 1jn\ ,ronment.il Prntectinn Aqenc y, Sept 2 ,? ,]980

N OX are presented in table A-23. Control cost esti-mates vary widely; the General Motors’ (GM) estimateof $720/car is about double that of EPA, and is 50 per-cent higher than Ford’s. Differences in technologyamong manufacturers, and the difficulty of allocatingthe costs of multipurpose components to particular ob-jectives (e. g., emissions reductions, as opposed to theresulting improvements in fuel economy or vehicle per-formance), probably account for a substantial amountof the variation. The differences narrow when NOx

controls are looked at alone: Ford, EPA, and Chryslershow only a $27/vehicle spread in estimates of savingsassociated with a change in standards from 1 to 2 gpmNOX—ranging from $48 to $75/vehicle. GM’s estimateis still substantially higher, at $188/vehicle.

Inspection and maintenance (1/M) programs offer analternative approach to reducing NOX emissions frommobile sources. A recent study concluded that addingNO, testing to an existing I/M program for HC andCO would add about $4/inspected vehicle, and that hav-ing 20 percent of the vehicles repaired (at an averagecost of $50 each) could result in about a 10-percent re-duction in NOx emissions. 51 An EPA analysis con-cluded that the cost-effectiveness of an I/M program forNOX control would range from $400 to $500/ton ofNOX eliminated if added to an existing HC/CO pro-gram, or $1,700 to $2, 700/ton if started up exclusivelyfor NOX control .52

5“(A Study of the Relationship Between Motor \rehicle Emiswms and At-tainment of National Ambient Air Qua] itv Standards, Part 1 Nitrogen Di-oxide, SRI International, Februar>. 1981.

~ ? Interna] EpA memo, Tom Cackette to M icbael P W’alsh, ,Jan 9 , 1981.

Table A-23.—Costs of Emissions Controls for Automobiles

Cost differential per vehicle: NOx costs per vehicle: NOX costs per vehicle:Autos 1983 cars v. uncontrolled 1 gpm v. uncontrolled 1 v. 2 gpmEPA . . . . . . . . . . . . . . . . . . . . . . 370C $123 50Ford . . . . . . . . . . . . . . . . . . . . . 500 167 48*GM . . . . . . . . . . . . . . . . . . . . . . 725 242 188Chrysler . . . . . . . . . . . . . . . . . . — — 75a1983 car costs are based on emissions standards of 0,41 HC/3.4 CO/1.0 NOX grams per mile.bAssumes that emission control costs of 1963 cars are equally divided between HC, CO, and Nox.CEPA estimates that this would drop to $330 by 1966 as systems are refined.dAssumes that 613 percent of cost estimated by Ford for CO, high altitude and NoX control— $80 per car—is attributable to NOx control, This is a high estimate, based

on Chrysler’s estimate that 60 percent of its costs for CO and NOX control Is due to NOx alone.

SOURCE: Michael P Walsh, “Motor Vehicle Emissions of Nitrogen Oxides,” OTA contractor report, Nov. 30, 1961.


A.6 POTENTIAL SECONDARY ECONOMIC EFFECTSOF EMISSIONS CONTROL PROGRAMS

Emissions controls and the associated costs are likelyto have the greatest effects on three sectors of theeconomy: high-sulfur coal mining, industries that de-pend heavily on electricity consumption, and the elec-tric utility industry. This section discusses ways in whichthese industries might be affected by a major programto reduce sulfur dioxide (S02) emissions in the EasternUnited States.

Potential effects on the coal industry are quantifiedon the basis of several hypothetical S02 emissions re-duction scenarios; qualitative estimates of the degree ofvulnerability are provided for electricity-intensive indus-tries and the electric utility industry. However, it shouldbe noted that both the degree and nature of the poten-tial impact on these sectors would depend on the typeand magnitude of the chosen control program, the wayin which reductions are allocated, and the way in whichcontrol costs are allocated. Thus, the discussions pro-vided below are intended to give only a general indica-tion of these sectors’ relative vulnerability to the effectsof emissions controls.

Coal Production and RelatedEmployment

Coal Reserves and Current Production

Many legislative proposals for controlling acid rainhave focused on reducing S02 emissions in the EasternUnited States. Emissions reductions designed to con-trol acid rain might cause significant shifts in the coalmarket by increasing the value of low-sulfur coals ascompared to high-sulfur coals. Because the sulfur con-tent of coal varies from region to region throughout theUnited States, any emission reduction strategy that re-lies even in part on “switching’ to lower sulfur coalscan potentially affect the regional distribution of coalproduction and employment. Social dislocations couldaccompany these changes in the coal market, as someareas experience rapid economic growth while othersdecline.

Figure A-6 shows the location of the Nation’s coaldeposits. Three factors influence regional coal produc-tion from these reserves: 1 ) mine-mouth prices (the costof production), 2) transportation costs (the distance be-tween the mine and the consumer), and 3) fuel charac-teristics (primarily a coal’s energy value and sulfur con-

tent). 53 Acid rain control measures would affect theexisting production patterns by increasing the value oflow-sulfur coal relative to high-sulfur coal, all other fac-tors remaining equal.

Table A-24 displays the distribution of each State’scoal reserves by sulfur content category. Figure A-7shows a distinctive difference in the sulfur content ofcoal reserves between the Eastern and Western UnitedStates. A large majority (74 percent) of coal reserves inthe Eastern United States are high in sulfur (greater than2.0 pounds per million Btu (lb/MMBtu) of S02). Bycontrast, the majority (72 percent) of Western reservesare low in sulfur (less than 1.2 lb/MMBtu). The twosignificant Eastern exceptions to this pattern are Ken-tucky and West Virginia, both of which have signifi-cant quantities of reserves above and below 1.2 lb/MMBtu.

Table A-25 displays each State’s coal production forthe utility market. The first column presents each State’scoal production, in millions of tons, for the utility mar-ket in 1980. The second column shows what propor-tion of that production would not allow utilities to com-ply with a 1.2 lb/MMBtu S02 emission limit withoutapplying control technologies. The third column pre-sents the percentage of this ‘‘noncompliance’ coal soldon the spot market, i.e. , sales not covered by a long-term contract between a utility and a mining company.Noncompliance coal sold on the spot market is likelyto be most vulnerable to more stringent S02 regulations.The final column shows the portion of noncompliancecoal exported to other States—an indicator of the po-tential efficacy of State-level policies designed to mini-mize coal market disruptions.

~IFIor ~ d,$( “ss, O1) ~~f the factors aflectrng t h e t hotce of ((MI i wc ~;cjngr~’s-

smnal Budget of fic e, 7?re Lrtillty, Industry, thr Coal .tlarkrt, and (he CleMAir A( t, April 1 !)82, and Martin Zlmrnerman, The L’ S Gal Industr} “1’hcEl onomlcs of Public Choice (Cambridge, Mass MI’1’ Press, 1981)

● ’l’he degree to wh)~h cuntracts usnstrain fuel-switching is a major uncer-tainty m this msalysls In 1980, 88 5 percent uf coal pure hased was purchasedon L ontrm t It is not t tear whether changes nr en\.lrunnlental re<qulatwns wouldabscsl\c pure hasem uf their contractual obllgatmrrs A contract t an t ont~ln prwvmwnf (c ~., ‘‘f[)~ e majeure’ clauses) whl( h d irtx tly a(idrms the (M]r+tlonsof pdrt ies [n the event uf [ hanges rn envlronmenta] regulatmns 13uver or seller( ouki be re]m ed of a]] or part of the contra( tua] ob]l~dtbns See S( (It t, ‘ ‘(~odlSupplY .Agreements, “ 23 Rock} Afountain i,aw [n~tlrure 1 0 7 ( 1979)


0


Table A-24.—Demonstrated Reserve Base by Sulfur Category(quantities in millions of tons, sulfur categories in lb SO2/MMBtu)

State <0.9 0.9-1.2 1.3-1.5 1.6-2.0 2.1-3.0 3.1-4.0 4.1-5.0 5.1-6.0 >6.0 TotalAlabama . . . . . . . . . . . . . . . . . . . 5 1,775 - - - ‘ - “ ‘-- ‘ -

Georgia. . . . . . . . . . . . . . . . . . . . 0 0Illinois. . . . . . . . . . . . . . . . . . . . . 0 0Indiana . . . . . . . . . . . . . . . . . . . . o 212Kentucky . . . . . . . . . . . . . . . . . . 0 10,210Maryland . . . . . . . . . . . . . . . . . . 0 1Michigan . . . . . . . . . . . . . . . . . . 0 0North Carolina . . . . . . . . . . . . . . 0 0Ohio . . . . . . . . . . . . . . . . . . . . . . 0 0Pennsylvania . . . . . . . . . . . . . . . 16 568Tennessee . . . . . . . . . . . . . . . . . 0 189Virginia . . . . . . . . . . . . . . . . . . . . 784 1,469West Virginia . . . . . . . . . . . . . . . 3,407 13,724

Eastern U. S. total . . . . . . . . . 4,212 28,149Alaska. . . . . . . . . . . . . . . . . . . . . 5,805 18Arizona . . . . . . . . . . . . . . . . . . . . o 0Arkansas . . . . . . . . . . . . . . . . . . 0 11Colorado . . . . . . . . . . . . . . . . . . . 7,800 2,212Idaho . . . . . . . . . . . . . . . . . . . . . . 0 0lowa . . . . . . . . . . . . . . . . . . . . . . o 0Kansas . . . . . . . . . . . . . . . . . . . . o 0Missouri . . . . . . . . . . . . . . . . . . . 0 0Montana . . . . . . . . . . . . . . . . . . . 84,247 32,786New Mexico . . . . . . . . . . . . . . . . 1,277 508North Dakota . . . . . . . . . . . . . . . 564 165Oklahoma . . . . . . . . . . . . . . . . . . 8 750Oregon . . . . . . . . . . . . . . . . . . . . 12 0South Dakota . . . . . . . . . . . . . . . 0 0Texas . . . . . . . . . . . . . . . . . . . . . o 0Utah . . . . . . . . . . . . . . . . . . . . . . 399 4,733Washington . . . . . . . . . . . . . . . . 843 16Wyoming . . . . . . . . . . . . . . . . . . 33,527 8,560

Western U.S. total . . . . . . . . . 134,482 49,761United States . . . . . . . . . . . 138,694 77,909

SOURCE: Adapted for Office of Technology Assessment by E. H. Pechan & Associates from U.S. Department of Energy, Demonstrated Reserve Base of Coal in theUnited States on Jan l, 1979, DOE/ElA-0280(79) May, 1981.

1,71240

9923,846

0110

587135458

2,93210,681

3320

234,841

4000

1,4102,7011,961

2800

1930

1580

1,00712,91123,592

1,074 1,7560 0

4,359 1,5811,304 5031,473 410

296 650 950 00 1,119

1,992 8,581154 154561 148

2,791 6,02914,005 20,440

0 0399 25260 43213 1,150

0 00

0 o0 01 1,5277 48

2,908 2,24426 332

6 074 00 12,6930 178

578 024,214 2,60628,685 20,84542,690 41,285

4380

3,151453749175

01,294

12,20362

1183,084

21,72600

74000

190000

1,524144

99o

1,033143

43,212

24,938

00

3,1072,0181,556

17826

06,6843,757

2340

3,53521,096

000000

123518

00

6040000000

1,24622,341

00

14,2481,9767,524

10700

4,4291,684

310

35530,353

00000

71210

0000

21000000

30230,655

o41,260

3,1618,472

0

05,5091,039

390

4,12863,616

00000

2,127472

5,559499

00

830000

958,835

72.451

6,7604

67,70510,62134,240

82612811

19,03530,428

9983,538

39,985214,277

6,155424411

16,2154

2,199995

6,077120,469

4,5419,9711,644

17366

12,6936,5021,580

70,014260,279474.556

Changes in Regional Coal Production,Employment, and Economic Activity

METHODS OF PROJECTING REGIONALCOAL PRODUCTION

This appendix projects regulation-induced changesin regional coal production using results from a com-puter model modified by ICF, Inc., from the DOE Na-tional Coal Model. ICF’s Coal and Electric UtilitiesModel (CEUM) makes it possible to compare: l) pro-jected regional coal production in 1990 (and 2000)assuming that current S02 emissions standards aremaintained, to 2) projected regional coal production in1990 (and 2000) insignificant S02 emissions reductions,designed to control acid rain, are required. The ICFmodel has been used to project the effects of acid raincontrol proposals by: the Environmental ProtectionAgency, the Department of Energy, the Edison Elec-tric Institute, and the National Wildlife Federation, and

National Clean Air Coalition. ICF did not perform themodel analyses discussed here for OTA, but for theother groups mentioned above.

CEUM is a “least-cost optimization model” thatchooses the combination of scrubbers, coal washing, andlow-sulfur coal substitution or blending that minimizesthe utility industry’s emissions reduction costs. 54Changes in utility coal consumption patterns alter re-gional patterns of coal production. These projected pro-duction shifts form the basis for OTA’s estimates.

This report uses four ICF S02 emissions reductionscenarios, and their attendant regional coal productionscenarios, to analyze the potential magnitude of coalmarket impacts:

1. Scenario I: a 5-million-ton decrease in utility S02

\~hIcJr ;l de~criptlon ~)f IC F’~ Coa] and E]ectnc Ut ill[ ies hf{)d~[ see the t’x~~ u-

ti\’e summary m ICF, inc , Capabdltws and Experknre In the Cod] and E/et(m Lrtillo lndustrws, May 1 9 8 1 .


Figure A-7.—Demonstrated Reserve Base bySulfur Content

Pounds of sulfur dioxide per million Btu

● SOURCES: Off Ice of Technology Assessment, and E. H. Pechan Associates,

2.

3.

4.

1982.

emissions by 1990, allocated according to a ‘‘ re-gional (31-State) least cost” approach;Scenario II: a 10-million-ton reduction of S02

emissions by 1990, allocated according to utilityemissions in excess of an emissions rate of 1.2 lb/MMBtu;Scenario III: a 13-million-ton reduction by 1990,allocated according to a formula similar to (2)above; andScenario IV: a 10-million-ton reduction, allocatedaccording to a ‘‘regional least cost’ approach,showing regional coal production shifts out to2000. 55

‘5S( cnarlf~ I wd\ perlorrrrcd by 1(:F for IX)E a n d E P A See itlterrra(l~reS(rd(r,y](.s f o r Redu( {ny L“(dlr} .SC)~ and NO, Em~ssmns, d r a f t repurt,%.plembcr 1981 S( cnarios 11 and 111 were performed b, ICF for the EdisonF:le[ trlt Instlto[t SctI the EE1 rntmo {latecf Fell 8, 1 9 8 2 , o n ICF anal, \Is of”the hl II( hell BIII ( S 1706) SC eoant) 11’ way performed b} IC F for the Natlorralk$’ii(]]ile }Jedcra[l(m a n d Na[r(jnal (Ilean A!r Coa]ltlon Sce Cos[ dncf CIMI Pro-(III[ [J(JO F;ffe( rs (J/ R(YIu( Iny E/et trx L’ri/Ir} Sulfhr DmYIcfc Em Is,sI(Ins, Nm14, 1981

The model cannot predict how various acid rain pro-posals would, in practice, be implemented. These sce-narios merely illustrate the potential magnitude anddirection of coal market shifts associated with variousreductions in S02 emissions, when costs to the utilityindustry are minimized. Some analysts assert that theICF model seriously underestimates the probable ex-tent of fuel-switching, while others suggest that its fuel-switching estimates are overstated. *

In addition, changes in model assumptions causefuture coal production estimates to vary considerably.OTA considers that the chosen scenarios reasonably rep-resent the relative magnitude of fuel-switching andscrubber use.

Several important factors that might influence the ac-curacy of ICF’s projections are:

Innovation in pollution control technology: Thelikely extent of fuel-switching depends on the costof that approach as compared to other emission re-duction options. The ICF model reflects the bestavailable estimates of current costs for various con-trol options. If innovations were to significantly re-duce the costs of control technology relative to fuel-switching, smaller changes in regional coal produc-tion would accompany any given level of emissionsreductions.Utility regulatory policy: State regulatory policiesmay make certain emissions reduction optionsmore attractive to utilities. For instance, provisionsthat allow utilities to pass increased fuel coststhrough to consumers without undergoing a ratehearing may make fuel-switching more attractiveto utility managers than the ICF model would sug-gest. ” * The final section of this appendix addressespotential effects of State regulatory policies ingreater detail.Transportation costs: Railroad rates govern thepenetration of low-sulfur Western coal-into East-ern and Midwestern utility markets. A rapid escala-

“Ft)r anal)rscs asserting that ICf-- urrcferesttmate\ fuel -swltc hlng, see the tes-(Imony of Chrrs Farrancf of Peabndy C n a ] C() on S 1706 to the (;ornmltteeon F.nvlronmcnt and Public }$’orks. LT S !$enate, ()( t 29, 1981 If thrs rj t h ecase, the pr~~yx tt{ms prc-sentccf here hate urrdermt trnatecf the m,i~nltude of r<, -gional redistribution of produc(lon

On the other band, utilit) analyses of how this bdl would he implementedfor their systems show little e~idence of potential coal market disruptions Ananalysis by American F~ectrlc Power (the Natmn largest utd ity and coal cxJn-sumer) states that cm]) 4 of their 27 units would switch to lower sulfur furls,while the others would retrofit scrubbers or be retired See AEP, ‘‘ Eccsnom icImpact Summary of Mitchell Bd] (S 1706) on Customers of the AEP SY,stem,Feb. 23, 1982,

● ● Many public utility commissions do not allow utilities [o earn a returnon capitaf investment (e. g., a scrubber) untd it becomes operational. Thus,he{ auw ch:inges in fuel prices can be passed on immediately to cunsurners,ut dlt ws mrght prefer fuel -swltchlrrg This could be counteracted somewhat b)prn\lslons allow Ing ut Illtles I() earn cash returns on ‘‘construction work in prcr~-rew’ before the mquipment be( nmcs operational The final sectmn of this ap-pendm surve)s and discusses Sta(e rwg-ulatory pollcles for publi( utdltles m theEastern United States


●

Table A-25.—Coal Production for the Domestic Utility Market

Percentage Percentage1980 production for noncompliance noncompliance

utility market Percentage sold on exported toState (millions of tons) noncompliance spot market other States

Alabama . . . . . . . .Arizona . . . . . . . . .Colorado . . . . . . .Illinois , . . . . . . . .Indiana . . . . . . . . .Iowa . . . . . . . . . . .Kansas . . . . . . . . .Kentucky . . . . . . .

East. . . . . . . . . .West . . . . . . . . .

Maryland . . . . . . .Missouri . . . . . . . .Montana . . . . . . . .New Mexico . . . .North Dakota. . . .Ohio . . . . . . . . . . .Oklahoma. . . . . . .Pennsylvania . . . .Tennessee . . . . . .Texas . . . . . . . . . .Utah . . . . . . . . . . .Virginia. . . . . . . . .West Virginia. . . .

North . . . . . . . .South . . . . . . . .

Wyoming . . . . . . .

15.810.513.653,427.3

0.40.7

112.473.938.5

1.25.0

27.917.015.334.3

2.750.9

7.627.0

8.513.853.130.822.389.7

82.50/o0.07.1

99.999.995.9

100.089.983.2

100.0100.0100.063.669.899.2

100.098.699.186.7

100.020.087.581.397.858.516.6

17.3 ”/00.00.46.68.3

14.529.316.519.011.822.8

6.90.00.3

13.618.917.329.917.60.01.1

10.68.17.58.80.9

10.1%0.02.8

66.022.1

0.081.772.975.168.724.733.551.9

1.220.826.598.630,134.6

0.07.1

71.039.446.130.1

9.9a"Noncompliance" coal is defined as coal that would not permit utilities to comply with an emissions limit of 1.2 lb of SO2/MMBtu

without applying control technologies.

SOURCE: From DOE/EIA Form 423 data, supplied to OTA by E. H. Pechan & Associates.

tion in Western rail rates could raise the deliveredprice of Western coal, thereby reducing the mag-nitude of regional shifts.Electricity growth rates: While the rate of growthin electricity demand should not significantly af-fect the extent of fuel-switching as opposed to othercontrol options, projected increases in the amountof coal produced by 1990 are highly dependent onassumptions about the rate of growth in electricitydemand.

FORECASTING COAL MINE EMPLOYMENTAND ECONOMIC CHANGES

OTA combined production estimates from the ICFmodel with coal-miner productivity and income data toproject the effects of acid rain control scenarios on re-gional employment and economic activity. Employmentin the coal-mining industry is determined by two fac-tors: the level of coal production (tons of coal) and therate of worker productivity (tons of coal produced perminer). Historically, employment levels have been af-fected more by changes in productivity than by changes

in production. * * * Therefore, employment forecasts .must provide for uncertainties about future productivity ylevels. This analysis presents projected coal-mineemployment changes as ranges reflecting differentassumptions about future productivity levels: a lowerbound of a 10-percent decline from 1979 productivitylevels and an upper bound of a 30-percent increase. *

‘ ● ● Over the period 1960 to 1970, coaf-rnine employment declined from190,(KN to 144,000, a 3-percent average annual decrease. over the same permd,coal product lcsn increased from 434 million to 613 mdllon tons, an a\erageannuaf int. rease of 4 pement The dtsc repancy between employment and pr{J-duction trends is accounted for by im reases in average coal-miner productivityduring this period ‘1’he average coal produc tmn per miner increased from about12 to about 18.5 tons per day-an average annual increase of nearly 4 percentThe im reining proportion of surface minmg-from 32 per(tnt of annual pro-duction (or 139 million tons) In 1960 to 44 percent (or 270 million tons) in 1970—accounts for some of the gains, since the average surface mmer produces aboutthree times as much coal per day as the average underground miner

“l”hese productivity ranges ha\e been chosen somewhat arbltraril}, The 30-percent Inc rcase m producti\,ity was chosen as one bound because It reflectsthe historic al maxrmum The 10-percent decrease was chosen to acc t)unt forfactors that may mntribute to decreased product l\ltY,, such as more stnntyntmine health and safety or surface redamat ion regulations, or a shlf[ fr(}nl sur-face to underground mrning After a steady decline over the past 12 years, pro-ductivity is finally begiming to rise again, but future trends are uncertain Fora discussion of factors affecting worker prvductivlt), In coal mining see oflceof Technology Assessment, Direct Use of’ Coaf, (MA-E-86, Aprd 1979, ( hIYr See also Electric Pnwer Research Institute, 7’he Labor Outlook fi)r theBlrumlnous Coal .\ fjning Indusrr?, EPR1 EA- 1477, final relx)rt, August 1980


These employment projections are combined with minerincome data to estimate the ‘ ‘direct’ income effects ofacid rain controls.

However, direct income effects do not reflect the fullimpact of changes in coal-mine employment. Economicactivities dependent on the coal-mining industry, suchas rail transport and retail services to coal-mine indus-try employees, are also affected. These indirect eco-nomic effects are likely to be quite significant, but areextremely difficult to estimate. Indirect effects includereduced employment, reduced income to the employed,or some combination of both. In this analysis, direct in-come effects are combined with an income ‘‘multiplier’—a very rough approximation of the regional economicactivity that depends indirectly on coal mining—to de-rive ‘‘total income effects of acid rain control sce-narios. * *

PROJECTED PATTERNS OF CHANGE

Table A-26 summarizes how 5-, 10-, and 13-million-ton S02 emissions reductions might affect regional coalproduction, employment, and economic activity. Sev-eral generalizations emerge from the analysis. First, themodel projects significant growth in coal production na-tionwide (about 60 percent) between 1979 and 1990.Second, regulations designed to control acid rain, eventhose calling for the largest emissions reductions, do notalter the projected increases in national production.Even with the additional costs of acid rain controls, coalis projected to retain its competitive advantage overother fuels.

Third, while acid rain control measures are not pro-jected to change nationwide production levels, the ICFmodel projects a redistribution of coal productionamong regions. Regions with low-sulfur reserves areprojected to experience production growth beyond whatwould occur under current regulations. On the otherhand, between 1979 and 1990, production in regionswith high-sulfur reserves is projected to decline belowcurrently projected 1990 levels, and—in the case of the10-million-ton and greater reductions of S02 emis-sions—below 1979 production levels as well. The pro-jected redistributions increase in magnitude as S02

emissions reductions increase, but by less than linearproportions. * Figure A-8 shows the projected changein regional coal production from 1979 to: 1 ) 1990 levels,

● ““I’(J .irrl\ft at tnl!Jl(wrllcr]l c,\tlnldtts, ()’1’A rIl\ Idt.\ prx!]e{ ted productl{)rlInc rt,t\t.\ })} St,it(.-l)\-SMtc. pr(du[ t I\ rt} (],ita cie\.t.]npcd from Doh; data ‘1’ht.wt.r]][)lf)~ ]i)cnt ( hanqcs ~rt. thcrr ( ornblncd w i t h rnlncr sa lary data to arrrve atdlrc( r )n( orr]t. rfl(.(1s In(ltrrt t {,( fmcmu( Impa( ts were rstlmatc{l uslrrg an ‘ ‘(.( ()-r)f]rr] I( lj,i\[ ((( I]n](lut. ‘‘ ~:[~r c,t( h St.il(, rnul[lpllcrs wt, re dt. \ t.l(lptxi h\ t .II( [I-I.i[ rnq ( h(. r.it ]( ~ ()! ln( t)rrlt cl{.rl\{,cl ir~jrrl [h(, ‘ ‘ I),tst. ‘ {Jr ‘ ,}jrlrI1ar\‘‘ \{.{ [{)r [{1 III.{ {)rf)t, flt,r]~ ({l Ir,)rrt tht ‘ ‘ wr\ J( t, ‘ or ‘‘ \(.( f)r](l<ir] ~(( tor ‘‘

● ,4$ [.m)\\ll,n\ ll,(lu{ tlon rt.qulr<nu.nt\ In( reaw Ix,}on(! A c crtarn IL,\{,l, II)t.prt)p{~rtl(,n (It rt,(lu( tl~)n\ [h,i[ ,irt, [)rr)lt( t{.(1 (() h{ m{.t })} ‘ ‘ fue-s\\ II( hlrlq’ (lt-( rt.a\t.s rrl,i[ I\ t, t f ) t ht. prr~~)ort ion rr){.[ I)\, S( rul)lx.rs

assuming no change in S02 standards; and 2) 1990 lev-els, assuming a 10-million-ton decrease in S02 emis-sions. * *

The areas most likely to experience significant growthin production are southern West Virginia, eastern Ken-tucky, and the regions west of the Mississippi (particu-larly Colorado). The regions most likely to experiencesignificant production declines include northern WestVirginia, Ohio, western Kentucky, and Illinois. How-ever, available model projections for 2000 suggest thatproduction declines below current levels may be reversedin the decade following 1990. Production levels are pro-jected to rebound due to general trends in the energymarket, such as growth in utility demand, and to thefact that an increasing number of new plants regulatedunder New Source Performance Standards will comeonline after 1990.

Employment patterns are projected to correspond tochanges in production. However, uncertainties regard-ing future productivity trends create a larger range ofuncertainty for employment effects than for productioneffects. The loss of portions of the market for high-sulfurcoal could reduce employment opportunities in Mid-western and northern Appalachian regions by about 10to 40 percent of projected 1990 coal-mining work forcelevels under current emissions standards. The areas ofnorthern West Virginia, Ohio, western Kentucky, andIllinois are projected to experience actual employmentdecreases below 1979 levels for emissions reductions of10 million tons and greater.

Future employment changes would be accompaniedby proportional changes in direct miner income andtotal monetary effects. For each of the high-sulfur coalregions of northern Appalachia and the Midwest, thesecosts range from $250 million to $500 million in directannual income losses to miners, and from $600 millionto $1,100 million in total (direct plus indirect) annualmonetary losses. The coal-related benefits in centralAppalachia range from $400 million to $550 million an-nually in direct income gains, and total annual incomegains of $750 million to $1,100 million. Estimates ofbenefits in the West range from $100 million to $150million in direct income gains and total income gainsof $500 million to $750 million per year. All estimatesare in 1981 dollars. These figures, particularlyin thecase of total monetary impacts, must be considered veryrough estimates.

Changes in coal-related employment and income maycause some additional community-level social and eco-nomic repercussions. In areas projected to experiencesignificant declines in employment, decreases in tax re\~-

‘ “01 the 90 nlrlll(]n tons O! annual produ[ tlon lo\( h\ [h~. t-;.i~tt,rn ancl hl 1(1-w,cstern hlqh -sulfur ( (MI rnarke[ h} 1 W(), alx)ut 50 rn dllon tons IS qalncd I)\,Ila\tcrn low -\ullur pr[xlu( t.rs and 4 0 nldllt)n torls t)i ;%’cst{.rrl pr(}du( c,r~

Table A-26.—Summary Table of Regional Coal Market Effects of Acid Rain Control Legislation

5-million-ton sulfur 10-million-ton sulfur 13-million-ton sulfurdioxide emission reduction dioxide emission reduction dioxide emission reduction

North Appalachia Region (Maryland, northern WestVirginia, Ohio, and Pennsylvania)Under current environmental regulations, annual coal

production is projected to increase approximately 10percent between 1979 and 1990; under a 5-million-tonacid rain control program no change in production isprojected over this period. Employment opportunitiesforegone are projected to range from 6,300 to 9,100jobs (a 10-percent reduction); because there is no pro-jected production change, employment changes from1979 levels will be a function of productivity changesonly. Direct income opportunities foregone by theregional economy are projected to be $160 million to$230 million; total income opportunities lost couldrange from $450 million to $640 million.

Central Appalachia Region (eastern Kentucky, southernWest Virginia, Tennessee, and Virginia)

Under current environmental regulations, annual coalproduction is projected in increase by about 50 per-cent between 1979 and 1990); under a 5-million-tonacid rain control program, a 62-percent increase isprojected over this period. Employment is projectedto be about 10 percent (8,800 to 12,700 jobs) greaterthan it would have been in 1990 under current regu-lations; projected employment changes from 1979levels range from 25- to 80-percent (21,800 to 69,900jobs) increase. Direct annual income opportunitiescreated in this region range from $230 million to$330 million; total annual income created rangesfrom $450 million to $840 million.

Under a 10-million-ton acid rain control program, pro-duction is projected to decrease by about 10 percentbetween 1979 and 1990. Employment is projected tobe 15 percent (9,800 to 14,100 jobs) less than it wouldhave been under the 1990 base case; projectedemployment changes from 1979 levels range from nochange to a 30-percent (23,000 job) decrease. Directincome opportunities foregone range from $250million to $360 million; total income foregone rangesfrom $630 million to $910 million. Available projec-tions for the year 2000 suggest these declines mayonly be temporary.

Under a 10-million-ton acid rain control program, pro-duction is projected to increase 70 percent between1979 and 1990.1990 employment levels are projectedto be about 15 percent (15,000 to 21,700 jobs) greaterthan they would have been in 1990 under currentregulations, and 38 to 99 percent (33,200 to 86,500jobs) greater than 1979 employment levels. Direct in-come opportunities created are projected to be $390million to $560 million; total income generatedranges from $1,030 million to $1,490 million.

Under a 13-million-ton acid rain control program, pro-duction is projected to decrease by about 13 percentbetween 1979 and 1990.1990 employment levels areprojected to be 20 percent (12,700 to 16,500 jobs) lessthan what they would have been in 1990 under cur-rent regulations, and 14 to 35 percent (10,800 to26,100 jobs) below 1979 employment. Direct incomeopportunities foregone range from $330 million to$470 million; total income foregone is projected to be$810 million to $1,170 million.

Under a 13-million-ton emission reduction, productionis projected to increase 75 percent between 1979 and1990.1990 employment levels are projected to be 16percent (17,300 to 25,000 jobs) greater than what theywould have been in 1990 under current regulations,and 40 to 100 percent (35,800 to 90,000 jobs) above1979 levels. Direct income opportunities created bythe projected increase in coal production range from$440 million to $640 million; total income generatedranges from $1,200 million to $1,700 million.

Table A-26.—Summary Table of Regional Coal Market Effects of Acid Rain Control Legislation (continued).—

5-million-ton sulfurdioxide emission reduction

Midwest Region (Illinois, Indiana, and westernKentucky)

Under current environmental regulations, annual coalproduction is projected to increase 31 to 34 percentbetween 1979 and 1990; under a 5-million-ton reduc-tion, production is projected to increase 12 percentover this period. 1990 employment levels are pro-jected to be 16 percent (5,400 to 7,700 jobs) less thanwhat they would have been in 1990 under currentregulations, and between a 13-percent (4,200-job)decrease and a 25-percent (8,000-job) increase from1979 levels. Direct income opportunities foregonerange from $140 million to $200 million; total incomeforegone ranges from $370 million to $530 million.

The Western United StatesUnder current environmental regulations, annual coal

production is projected to increase approximately 138percent between 1979 and 1990; under a 5-million-tonacid rain control program, production is projected toincrease 145 percent over this period. 1990 employ-ment levels are projected to be 3 percent (1,200 to1,700 jobs) higher than what they would have been in1990 under current regulations, and 80 to 160 percent(16,600 to 32,900 jobs) above 1979 levels. Direct in-come opportunities created by acid rain controls areprojected to range from $30 million to $40 million;total income benefits are projected to be $120 millionto $170 million.

—— —10-million-ton sulfurdioxide emission reduction

Under a 10-million-ton acid rain control program, pro-duction is projected to decrease 10 percent between1979 and 1990. 1990 employment levels are projectedto be 33 percent (10,500 to 15,200 jobs) below whatthey would have been in 1990 under current regula-tions, and 6 to 35 percent (1,900 to 11,300 jobs) lessthan 1979 employment. Direct income opportunitiesforegone are projected to range from $270 million to$390 million; total income foregone ranges from $770million to $1,100 million. Projections for the year 2000suggest these declines may be reversed in the period1990 to 2000.

Under a 10-million-ton acid rain control program, pro-duction is projected to increase 158 percent between1979 and 1990.1990 employment is projected to be13 percent (4,600 to 6,700 jobs) greater than what itwould have been in 1990 in the absence of acid raincontrols, and between 95 and 180 percent (19,100 to36,300 jobs) greater than 1979 levels. Increases indirect income opportunities range from $120 millionto $170 million; total income increases are pro-jected to range from $510 million to $740 million.

SOURCE: Office of Technology Assessment, based on coal production estimates from ICF, Inc.

1 3-million-ton sulfurdioxide emission reduction

Under a 13-million-ton sulfur dioxide emission reduc-tion, production is projected to decrease by 17 per-cent between 1979 and 1990. Employment is pro-jected to be 38 percent (12,100 to 17,400 jobs) belowwhat it would have been in 1990 without an acid raincontrol program; projected employment decreasesfrom 1979 levels range from 13 to 40 percent (4,200 to12,900 jobs). Direct income opportunities foregonerange from $.310 million to $480 million; total in-come foregone ranges from $870 million to $1,200million.

Under a 13-million-ton sulfur dioxide emission reduc-tion, production is projected to increase 165 percentbetween 1979 and 1990. Acid rain controls are pro-jected to increase employment opportunities by 20percent (6,800 to 9,800 jobs) over what they wouldhave been in 1990 without any change in environmentregulations. 1990 employment levels are projected tobe 105 to 196 percent (21,000 to 39,300 jobs) greaterthan 1979 levels. Direct income opportunities createdin the region are projected to range from $180 mil-lion to $250 million; total income benefits rangefrom $750 million to $1,100 million.

.


Figure A-8.— Regional Coal Production: Effects of a 10. Million. Ton Sulfur Dioxide Emission Reduction

enues could cause the quantity or quality of commu-nity services to decline. In areas projected to experiencerapid increases in employment, the capacity of commu-nities to provide adequate health care, housing, educa-tion, etc. , may be strained.

RESULTS OF OTHER STUDIES

The United Mine Workers (UMW) has also calcu-lated the potential effects of a 10-million-ton reductionin S02 emissions, allocated as in OTA’s Scenario II.The UMW analysis presents three sets of estimates ofeffects on mineworker employment and economic ac-tivity in high-sulfur coal areas only, assuming that fuel-switching would account for 50, 75, or 100 percent ofthe required reductions. However, the UMW analysismade no calculation of gains in employment and eco-nomic activity in low-sulfur coal areas, or of the net ef-fects of the 10-million-ton emissions cutbacks.

Table A-27 shows the UMW projections of job losses,direct annual economic losses, and total annual econom-ic losses for the three levels of fuel-switching. Using aDOE estimate that between 50 and 75 percent of the

SOURCE: Office of Technology Assessment, adapted from ICF, Inc

reductions required under a major acid rain control pro-gram would be met by fuel-switching, the UMW ‘cal-culated that between 40,000 and 60,000 coal mining jobswould be lost in high-sulfur coal areas, producing di-rect annual income losses of $1.1 billion to $1.6 billion,and total economic losses ranging between $3.0 billionand $4.6 billion.56

For comparison, OTA estimates of the net effects ofthe 10-million-ton reduction on high-sulfur coal areasare also presented in table A-27. Two factors must beconsidered in comparing these estimates:

1. OTA used projections of increases in coal produc-tion, including increases due to construction of newelectricity plants, through 1990, and comparedthem to projections of how further emissions con-trols would affect these new production levels.UMW estimates are calculated from 1981 produc-tion levels, assuming that no changes in produc-tion occur up to the time that controls would beimplemented.

~~~r~ltc{l hf lne L%’orkers, ‘‘ F,mpl(n rnrnt In)pa( ts of A( id Rain. .Junc 1983


Table A-27.—Employment and Economic Effects on High-Sulfur Coal. ProducingAreas of a 10-Million-Ton Reduction in S02 Emissions—

Comparison of UMW and OTA Analyses

UMW estimatespercent of emissions OTA estimatesreductions achieved

through fuel switchingChange Change

from 1990 from actual50 75 100 base casea 1979 levels

Employment Iossesb . . . . . . . . . . . . . 40,000 60,000 80,000 23,000-33,000 9,000-38,000

Direct annual economic losses(millions 1981 dollars) c . . . . . . . . . . . . $1,100 $1,600 $2,100 $600-$800 $200-$1,100

Total annual economic losses . . . $3,000 $4,600 $6,100 $1,600-$2,300 $600-$2,700

aOTA assumes, based on ICF analyses, that the requisite emissions reductions will be met by a combination of fuel-switchingand scrubbers The base case assumes no change in environmental regulations.

bThese employment losses occur over the period required to implement the pollution reductions. The ranges reflect uncer-tainty in future productivity levels OTA bounds employment and economic estimates by assuming that productivity mightrise as much as 30 percent or decrease by as much as 10 percent between 1979 and 1990,

cAnnual monetary estimates assume implementation of emissions reductions over 10 years, and that shifts in coal produc-tion are distributed equally over that period

SOURCE Office of Technology Assessment, based on coal production estimates by ICF, Inc

2. In the OTA estimates, employment losses in high-sulfur coal areas are partially compensated for byemployment gains. Thus, the OTA estimates areof the net effects in high-sulfur coal-producingregions. No projected employment increases arefigured into the UMW analysis.

OTA’s best estimates of potential effects on high-sulfur coal regions show employment impacts about halfas large as those estimated by UMW, assuming 50 to7.5 percent fuel-switching. * The most pessimistic of theOTA estimates—38,000 jobs lost from actual 1979 levels—approximates the low-end UMW figure of 40,000.

Possible means of’ preventing or decreasing coal minerunemployment that may ensue from acid rain controllegislation are discussed in chapter 7 under question 8.They include mandating control technologies to achieveemissions reductions, thereby prohibiting fuel switch-ing and employing sect ion 125 of the Clean Air Act torestrict coal consumption to ‘‘local or regional coals.

The net effect of acid rain legislation on nationwidecoal product ion, employment, and economic activity,howevrer, also includes the offsetting increases inemployment and economic activity in low-sulfur coalregions. When these are considered in aggregate, OTAestimates that no significant changes in employment andeconomic activity result from control-induced produc-t ion changes.

Electricity-Intensive Industries

OTA used 1979 and 1980 data from the LT. S. CensusBureau’s Annual Survrey of Manufacturers to assess theelectrical energy dependency of approximate}’ 450 typesof industries.57 Specific industries for which electricity

represents 4 percent or more of the total value ofshipments, and/or 10 percent or more of the total ‘‘val-ue added, * are listed in table A-28. The 17 industriesidentified in the table are largely concentrated in theareas of primary metals; chemicals—particularly indus-trial inorganic chemicals; and stone, clay, and glassproducts. The identified industries account for a dis-proportionate share of U. S. industrial electricity use—although they account for only 2 percent of total valueof shipments and 2 percent of total value added byAmerican manufacturers, they purchase approximately25 percent of the electricity sold to industry, and accountfor about 16 percent of utility revenues from industrialelectricity sales.

Five of these industrial categories—electrometallur-gical products, primary zinc, primary aluminum, alka-lies and chlorine, and industrial gases—are especiallyelectricity intensive; the cost of purchased electricityequals about 40 percent or more of their total valueadded, and about 10 to 25 percent of their total valueof shipments. These industries might be considered most

99-413 0 - 84 - 14 : QL. 3

200 . Acid Rain and Transported Air Pollutants: lmplicationS for Public Policy

Table A.28.—Statistlcs on Electricity-intensive industries

Electricity cost as Electricity Ratio toValue of Electricity percent of: rate industrial

S IC sh ipments purchased Va lue Value of ¢/kWh average rateIndustry code (10° 1980$) (10 6 kWh) added shipments (1982$) (3.84¢/kWh)Cotton seed oil mills. . . . . . . . . . . . . . .Manufactured ice . . . . . . . . . . . . . . . . .Particle board . . . . . . . . . . . . . . . . . . . .Alkalies and chlorine . . . . . . . . . . . . . .Industrial gases . . . . . . . . . . . . . . . . . .Other industrial inorganic

chemicals . . . . . . . . . . . . . . . . . . . . .Carbon black. . . . . . . . . . . . . . . . . . . . .Reclaimed rubber . . . . . . . . . . . . . . . . .Cement, hydraulic . . . . . . . . . . . . . . . .Lime . . . . . . . . . . . . . . . . . . . . . . . . . . . .Mineral wool . . . . . . . . . . . . . . . . . . . . .Electrometallurgical products . . . . . .Malleable iron foundries . . . . . . . . . . .Primary zinc. . . . . . . . . . . . . . . . . . . . . .Primary aluminum . . . . . . . . . . . . . . . .Other primary nonferrous metals . . . .Carbon and graphite products . . . . . .

20742097249228122813

281928953031324132743296331333223333333433393624

1,033.7169.6512.4

1,354.11,539.6

12,095.9498.0

38.33,962.4

598.82,235.41,249.3

521.2413.1

6,979.91,906.61,183.3

540.7460.7825.1

10,679.511,958.6

37,092.0540.4

75.49,237.9

813.82,703.56,814.31,015.51,487.8

72,279.14,279.42,171.8

10.7 2.015.6 11.011.4 4.845.5 19.642.4 24.5

13.9 7.513.3 3.512.2 7.815.3 8.210.8 5.17.3 4.0

42.0 13.811.9 7.051.7 8.339.3 15.615.6 5.1

7.5 4.2

4.614.703.442.893.66

2.863.784.624.084.383.822.944.172.671.752.662.64

1.201.230.900.750.95

0.750.991.201.061.140.990.771.090.700.470.690.69

SOURCE: US. Census Bureau, 1980 AnnualSurvey of Manufacturers: Fuels and Electric Energy Consumed, August 1982.

sensitive to potential increases in the cost of electricalpower resulting from further control of S02 emissions.For all five of these industries, a substantial proportionof production occurs in the 31 Eastern States.

Primary zinc is the most concentrated industrial cat-egory —only five producers currently operate in theUnited States. The three largest manufacturers arelocated in Pennsylvania, Illinois, and Tennessee, andaccount for approximately three-quarters of the Nation’scurrent production. The zinc industry appears to be par-ticularly vulnerable to increases in the cost of production—U.S. annual production capacity fell from about 1million tons to 300,000 tons over the past decade, andforeign producers have captured a substantial share ofdomestic sales.58

Primary aluminum, by far the largest of these indus-tries, is produced in 13 of the 31 Eastern States.Although two non-Eastern States—Texas and Washing-ton—currently have the largest production capacities,the Eastern United States currently accounts for about60 percent of national production capabilities. Major pro-ducers in the region include: Alabama, Arkansas, In-diana, Kentucky, Louisiana, Missouri, New York,Ohio, and Tennessee.59

Production of alkalies and chlorine is about equallydivided between the Eastern and Western regions of theUnited States. Louisiana accounts for nearly one-quar-ter of national output; the 17 other Eastern States in

~IJpc~~O~~ ~CJ~~u~lC~tlon, James Kennedy, Burcdu of Industrial F,(onoml{s,

U S Department of Commerce, October 1983‘gIbid

which these chemicals are produced together accountfor a slightly smaller proportion of production. GO Ala-bama, New York, Michigan, and West Virginia are thefifth, sixth, eighth, and ninth largest producing Statesin the country, respectively.

Information on the distribution of industrial gas pro-duction is limited, due in part to confidentiality re-quirements for protecting individual manufacturers.Available data indicate that Texas and California werethe highest producing States in the late 1970’s, and showsubstantial amounts of production in the following East-ern States: Alabama, Delaware, Illinois, Louisiana,New Jersey, New York, Ohio, Pennsylvania, and Ten-nessee.61

Over 90 percent of U.S. electrometallurgical prod-ucts (i. e., specialized metal alloys made with such metalsas molybdenum, manganese, and chromium) were pro-duced in the 31 Eastern States in 1981. Ohio accountedfor about one-third of national production; six additionalStates—Alabama, Kentucky, New York, South Caro-lina, Tennessee, and West Virginia—together ac-counted for slightly under one-half of national produc-tion. The industry is highly vulnerable to foreigncompetition, as countries with deposits of the necessaryores are rapidly developing their own production capa-bilities. 62

CoPerSorla] ~ommunlcatlon, Frank Maxey, Bureau of Industrial Et onon]ics,

U.S Department of Commerce, october 1983b! IbidCtpersona] ~ommuniatlon, I’om Jones, Bureau of Nlmes, U S Department

of the Interior. December 1983 ‘


Uncertainties about how utilities might apportioncontrol-related increases in electricity rates make it dif-ficult to assess the likely extent of financial effects onelectricity-intensive industries. As shown in columns 3and 6 of table A-28, many of these industries are large-scale electricity consumers, and pay relatively low elec-tricity rates. If control costs were apportioned to usersprimarily on the basis of current rates (i. e., increasingexisting rates by a uniform percentage for all users),effects on these industries, although potentially signifi-cant, would not be disproportionate to cost increasesundergone by all electricity consumers. However, if con-trol costs were apportioned primarily on the basis of elec-tricity consumption (i. e., increasing existing rates bya uniform mill/kWh fee for all users), percentage rateincreases would be highest for those industries currentlypaying low electricity rates. Effects could be particularlysevere for those industries having both low rates andhigh electricity dependency-primary aluminum, alka-lies and chlorine, electrometallurgial products, and pri-mary zinc.

Utilities in the Eastern 31 States*

The amount of SO2 that an individual utility musteliminate from its emissions is, of course, the primarydeterminant of the effect of acid rain control legislationon a given company’s finances. Such factors as each util-ity’s ability to raise capital to cover construction costsand regulatory policies in any given State further deter-mine a utility’s ability to pay for required reductionswithout adverse financial effects.

To address the utility sector’s vulnerability to furtheremissions reductions, this section will: 1 ) present 1980State-average S02 emissions rates for coal- and oil-burn-ing plants to indicate the potential extent of additionalcontrol requirements, 2) use available financial indica-tors for 1980 to assess the health of each State’s utilitysector, 3) assess the implications of State regulatory pol-icies in 1980-81 for utility finances, and 4) integrate thefirst three types of information in concluding observa-tions, identifying areas of particular vulnerability, wherepossible.

Current Emission Ratesand Generating Capacities

Figures A-9 and A-10 rank States in the EasternUnited States according to their coal- and oil-fueled elec-trical generating capacities, and by average 1980 emis-

“’1’h]s wc ti[}n hased prlmanly on Kathleen (;(,le, l)u,ine (;hapman, and(Illfforci RossI, ‘‘ F’]nan{ Ial dn(l Rcqulat,,r) Fa( tors .Affc{ tln~ the State a n dR{glf,nal Econnml< Impa( t ,)1 Sulfur oxide Emlssiuns [:nntrol, p r e p a r e d

for the of fi{ c of ‘1’tw hnc)log} ,~ssc~smcnt. L’ S [;(]ngrcss, August 1982

sion rates for all coal- or oil-fueled plants in the State.The greater a State’s dependence on either of these fossilfuels, and the higher its average S02 emission rate, thegreater the likelihood that proposed emissions controlswould require additional utility expenditures to reduceemissions. States with the greatest probability of exten-sive expenditures for emissions control appear in theupper left portion of each table; those with the least,appear at the bottom right. Overall, emission rates forcoal-fired utilities are substantially higher than for oil-fired facilities; thus, many more States would be exposedto significant control expenditures on the basis of cur-rent utility coal combustion than oil combustion. De-tailed estimates of S02 emissions reductions required,by State, under a number of alternative control scenar-ios, are provided in section A. 3 of this appendix.

Utility Financial Positions

Ultimately, a utility recoups its emission-reductionexpenditures by selling power to customers in its serv-ice area, or to other utilities. However, a utility mustshoulder the burden of pollution control expendituresfrom the time they are made until it is allowed to begincharging customers for them. Substantial capital invest-ment is required to retrofit existing powerplants withemissions control devices, or to build newer, cleanerpowerplants. Capital investment may also be necessaryto modify existing powerplant operations to permit theburning of low-sulfur fuel. The utility’s capacity to fi-nance these expenditures depends in large part on itsability to attract investment capital.

To place the potential capital-raising burden associ-ated with acid rain control into perspective, estimatedcosts of major control programs can be compared to ac-tual utility construction expenditures. Over 5 years(1978 through 1982), electric utilities spent approxi-mately $180 billion (1982 dollars) for construction inthe United States ;63 potential construction costs of major

acid rain control proposals over a similar 5-year periodmight range from about 5 to 20 percent of this figure,depending on the particular proposal. Control costswould constitute a higher proportion of construction ex-penditures for particular States and/or utilities fromwhich large emission reductions would be required.Such capital-raising burdens may be particularly criticalfor those utilities already scheduled to replace or retirea substantial proportion of plants over the period inwhich further emissions controls would be implemented.

A number of indicators are in use to assess utilities’competitive positions in capital markets, and no singlemeasure of financial well-being can adequately charac-

“>lrrrdl 1 ,ym h< Pwrx c, I:cnncr & Smith, [m , ‘‘ UIIIItY lndustn,, A St.it iwl( ,il

R(A I(’W (Prcllmln.in ), April 1 %’;


Figure A-9.—Coal-Based Generating Capacities and SO2 Emissions RatesCoal dependency

(Share of total electric-generating capacity)

a Numbers in parentheses are state-average SO2 emission rates for coal-burning plants, expressed In Ibs. of S02 Per million Btu

SOURCE Off Ice of Technology Assessment, from E H Pechan & Associates, Inc., and K. Cole, et al., “Financial and Regulatory Factors Affecting the State andRegional Economic Impact of Sulfur Oxide Emissions Control, ” OTA contractor report, August 1982.

Figure A-10. —Oil-Based Generating Capacities and S02 Emissions Rates

Oil dependency(Share of total electric-generating capacity)

Average SO2 emissionrates from coal-firedutilities (lb permillion Btu)

aNumbers in parentheses are State. average SO2 emission rates for oil-burning plants, expressed in Ibs. of SO2 Per million Btu.

SOURCE Off Ice of Technology Assessment, from E. H Pechan & Associates, Inc , and K. Cole, et al., “Financial and Regulatory Factors Affecting the State andRegional Economic Impact of Sulfur Oxide Emissions Control, ” OTA contractor report, August 1982.


terize a utility’s prospects. However, two major finan-cial criteria were selected to describe utility financial con-ditions at the State level: 1 ) return on common equity(ROCE), and 2) bond ratings. The first represents com-mon stockholders net earnings during a given year—in-dicating the utility’s current profitability. The secondrepresents experts’ judgments about the utility’s long-term ability to reliably repay debt. The lower a util-ity’s bond rating, the higher the interest rate it will needto offer to induce investors to purchase bonds.

Table A-29 categorizes States according to 1980 dataon whether more than 50 percent of their electrical pow-er was generated by utilities with: 1 ) bond ratings ofA or better, and 2) ROCEs above the 1980 national me-dian of 11.1 percent per year. Column A lists Statesmeeting both of these criteria; these States may be con-sidered to have a relatively healthy investor-owned elec-tric utility sector. Column D lists States that met nei-ther of the above criteria. These eight States may beregarded as particularly’ vulnerable to measures requir-ing utilities to generate additional capital for pollution-control purposes. Columns B and C show States fail-ing to meet either of the two criteria.

Utilities may be at greater risk from capital-raisingneeds if control-related expenditures must be added to

significant amounts of non-control-related construc-tion—either to replace retired plants or to accommodateincreasing electricity demand—during the period inwhich further controls would be implemented. Whileincreasing demand for electricity could, in itself, posi-tively influence utilities’ positions in capital markets, re-quirements for replacing retired plants carry high capitalcosts without necessarily enhancing utility positions.States in which more than 20 percent of current gener-ating capacity is scheduled for replacement by 1995 in-clude: Arkansas, District of Columbia, Maryland, Mas-sachusetts, New York, and Rhode Island.

State Regulatory Policies

Public utility commissions (PUCs) in each State makenumerous regulatory decisions that affect a utilitysability to pass on costs associated with emissions con-trol. PUC regulatory policies vary widely from State toState; 65 they may also change over time in response to

Table A-29.—Summary of 1980 Utility Financial Conditions by Statea

A. High bond, high ROCE B. High bond, low ROCE

States in which more than 50 percent of States in which more than 50 percent ofgenerated power was from utilities with generated power was from utilities withbond ratings of Aa or A, and ROCEs of bond ratings of Aa or A, and ROCEs11.1 percent or lower: (national median): below the national median:

Iowa DelawareKentucky IllinoisMaryland b IndianaMassachusetts b New Yorkb

Minnesota Rhode Islandb

Mississippi South CarolinaNew JerseyWisconsin

C. Low bond, high ROCE D. Low bond, low ROCE

States in which more than 50 percent of States in which more than 50 percent ofgenerated power was from utilities with generated power was from utilities withbond ratings of Baa or lower, and ROCEs bond ratings of Baa or lower, and ROCEsabove the national median: below the national median:

Alabama Arkansas b

Georgia ConnecticutLouisiana FloridaMissouri MaineNew Hampshire MichiganNorth Carolina PennsylvaniaOhio VermontWest Virginia Virginia

aBased on data from 106 surveyed utilities in the Eastern 31-State region Extremely small utilities, utilities with no generating

capacities (electricity distributors), and utilities with no coal or oil generating capacities have been excluded.bStates in which more than 21) percent of current generating capacity is scheduled for replacement by 19%,

SOURCE Office of Technology Assessment, adapted from K Cole, et al., ’Financial and Regulatory Factors Affecting theState and Regional Economic Impact of Sulfur Oxide Emissions Control, ” OTA contractor report, August 1982


changing economic and political conditions. Imposingstricter emissions controls at the Federal level might in-duce considerable changes in affected States’ utility reg-ulations; thus, current regulations may not reliably in-dicate how State-level policies would influence utilityfinances. However, to demonstrate the range of currentregulatory conditions, survey information on five majorregulatory policies for each of the Eastern 31 States dur-ing 1980-81 is outlined in table A-30.

Two of the surveyed policies directly concern the de-lay required before adjustments in utility costs can bepassed on to consumers. Each involves short-term de-lays—the number of months required, on average, forState utility commissions to rule on requests for rate in-creases (co1. 4), and the number of times per year thatutilities are allowed to adjust electricity rates according

to those utilities for which switching to more expensive,low-sulfur coal or oil is a potential means of meetingmore stringent emissions limits.

Three of the policies assessed in table A-30 affect themanner in which utility rates are calculated. PUCs mustdetermine a total amount of utility expenses and costs,or calculated revenue requirements, allowed to bepassed on to consumers, in order to set a utility’s elec-tricity rates. One major component of these costs is thereturn on capital investments. The first column of tableA-30, “allowed return on common equity” or ROCE,shows the maximum return to investors allowed by eachState, calculated as a percentage of a utility’s assets, orrate base. The second column of the table, ‘ ‘amountof CWIP allowed in rate base, indicates the extent towhich ‘ ‘construction work in progress’ (CWIP) is con-

to changes in fuel costs (co1.lowable fuel cost adjustments

3). The frequency of al- sidered a part of the utility’s assets for ratemakingis particularly significant purposes.

Table A-30.—Major State Regulatory Policies

Average numberAllowed Amount of Frequency of of months for

ROCE CWIP allowed adjustment for rate decisions Type ofState (median: 14.25) in rate base fuel price changes (median: 8.5) test year

Alabama , . . . . . . . . . . . . . .Arkansas . . . . . . . . . . . . . . .Connecticut . . . . . . . . . . . .Delaware . . . . . . . . . . . . . . .Florida . . . . . . . . . . . . . . . . .Georgia . . . . . . . . . . . . . . . .Illinois . . . . . . . . . . . . . . . . .Indiana. . . . . . . . . . . . . . . . .lowa . . . . . . . . . . . . . . . . . . .Kentucky . . . . . . . . . . . . . . .Louisiana . . . . . . . . . . . . . .Maine . . . . . . . . . . . . . . . . . .Maryland . . . . . . . . . . . . . . .Massachusetts. . . . . . . . . .Michigan . . . . . . . . . . . . . . .Minnesota . . . . . . . . . . . . . .Mississippi . . . . . . . . . . . . .Missouri. . . . . . . . . . . . . . . .New Hampshire . . . . . . . . .New Jersey . . . . . . . . . . . . .New York . . . . . . . . . . . . . . .North Carolina . . . . . . . . . .Ohio . . . . . . . . . . . . . . . . . . .Pennsylvania . . . . . . . . . . .Rhode Island . . . . . . . . . . . .South Carolina . . . . . . . . . .Vermont . . . . . . . . . . . . . . . .Virginia . . . . . . . . . . . . . . . .West Virginia . . . . . . . . . . .Wisconsin . . . . . . . . . . . . . .

12.8515.014.815.015.513.3316.515.8313.3514.2514.3315.1314.014.3113.2514.012.8513.7114.7514.015.513.8715.8615.6314.1313.8814.515.014.012.72

100 ”/0100%a

o100 ”/0VariesVariesVaries

o0

100 ”/0100 ”/0

o100 ”/0

o100%100 ”/0Varies

o0

VariesSmall % b

100 ”/0Varies

Small 0/0o

100%Small 0/0

100%Varies

o

QuarterlyMonthlyMonthlyMonthlyMonthly

QuarterlyIrregular-as needed

QuarterlyMonthlyMonthlyMonthly

QuarterlyMonthly

QuarterlyMonthlyMonthlyMonthly

No clauseQuarterly or monthlyIrregular-as needed

Monthly3/year

BiannuallyYearly

QuarterlyBiannuallyNo clauseBiannuallyBiannually

Monthly

610

5786

116

121012

9769

126

1168

117998

1221

5108.5

HistoricalHistoricalHistoricalForecastForecastForecastForecastHistoricalHistoricalHistoricalHistoricalHistoricalForecastHistoricalForecastForecastForecastHistoricalHistoricalForecastForecastHistoricalForecastForecastHistoricalHistoricalHistoricalHistoricalHistoricalForecast

aCWIP to be in service within 1 year is allowed.b"Small %” indicates that less than 1O% of CWIP IS allowed.

SOURCE. K. Cole, et al., “Financial and Regulatory Factors Affecting the State and Regional Economic Impact of Sulfur Oxide Emissions Control, ” Off Ice ofTechnology Assessment contractor report, August 1982.


If a State allows construction work in progress(CWIP) to be included in the rate base, utilities beginto earn returns on control-related expenditures as soonas they are made; if not, capital improvements must befinanced by the utility until the scrubber or other plantmodification is actually operating—a period of up to 4or more years. For utilities in weak financial positions,the ability to recoup expenditures during a planning andconstruction period of 4 years or longer may be a sig-nificant factor in deciding what means to use to complywith stricter emissions controls. Consequently, Statesallowing little or no CWIP in the rate base may makecapital-intensive approaches to S02 abatement less at-tractive, especially to financially troubled utilities. Suchutilities could choose to switch to higher priced, lowersulfur fuels, even when costs for doing so are higher overthe long run. Although State PUCs vary considerablyin their CWIP expenditure policies, decisions onwhether to allow C WI P in the rate base are often madeon a case-by-case basis, except in States where allow-ing CWIP is prohibited by statute. Some analysts con-sider that States are considerably more likely to allowCWIP for pollution control expenditures to enter a util-ity’s rate base.66

It should be noted, however, that some PUCs chooseto substitute higher allowed rates of return for allowingCWIP in the rate base as a means of increasing utilityrevenues during periods of construction activity. For ex-ample, table A-30 shows that the States of Indiana,Maine, New York, and Pennsylvania allowed rates ofreturn to exceed 15 percent in 1980, while including littleor no CWIP in the rate base. Available data did notpermit OTA to estimate the probable effects of such asubstitution on control choices.

Finally, the kind of “test year’ selected to providedata on expenses and costs (col. 5) can also influencecalculated revenue requirements. In times of risingcosts, historical test years may tend to understate util-ity expense estimates, while forecast test years can allowfor the projected effects of inflation.

State regulatory policies for 1980-81 are, of course,an imperfect indicator of the probable regulatory climateover the decade or more required to implement furtherS02 restrictions. Public utility commissions could re-spond to control requirements by adopting policies morefavorable to capital construction or fuel-switching, par-ticularly in States burdened with large S02 reductionrequirements. Such responses are virtually impossibleto predict, however; PUCs are affected by a broad ar-ray of political and institutional conditions, and must,in their regulatory decision making, balance consumerand producer interests. Concurrently, coal-producing

“’~(,r\lJnd] [ (,rnlnunl( df ll~n, ~11( hdr] ~’ol(>y, ~.it]onal A\\(x Idli(jn of ~ttqu],i-Ior} L’1 Il]lj ( :orrlr]lljsi(jrl{.rj, St. ptt, mtxr I ‘)8 1

States could constrain utility options for meeting tougheremissions standards by requiring continued use of in-State produced coal. Despite these uncertainties, the in-formation provided in table A-30 can be used as ageneral barometer of the favorableness or unfavorable-ness of a State’s current regulatory climate.

Combined Indicators

In this section, the three sets of State-level indicatorssurveyed above- 1980 utility emission rates from coal-and oil-burning plants, measures of short- and long-termutility profitability for 1980, and State regulatory pol-icies for 1980-8 1—are integrated to provide an overallpicture of current utility-sector vulnerability to stricteremissions control. It is important to note, however, thatthis provides only a surrogate for assessing the finan-cial effects of controls at the same time they would beimplemented. In addition, changes in such factors asdemand for electricity, financial viability of nonfossil fuelelectricity generation, interest rates, inflation, and theprice of coal, oil, and gas could greatly affect the rela-tive vulnerability of the region’s utility companies.

Eight States are identified in table A-29 as having fi-nancially weak utilities—Arkansas, Connecticut, Flor-ida, Maine, Michigan, Pennsylvania, Vermont, andVirginia. Three of these States have coal-fired utilityemission rates of at least 2 lb SO2/MMBtu: Florida(3.5), Pennsylvania (2.8), and Michigan (2.()). How-ever, less than a third of Florida’s electricity-generatingcapacity is coal-fired; more than half depends on oil,with 1980 S02 emissions averaging 1.6 lb/M MBtu.When emission rates from all utility fuel sources are con-sidered, only Pennsylvania is among the upper 15 Statesin the region, ranking 11th with an average rate of’ 2.5lb S02/MMBtu.

Pennsylvania utilities may also be of particular con-cern due to current State regulations governing fuel costincreases and calculated revenue requirements. WhileFlorida and Michigan utilities are allowed monthly fuelcost adjustments, those in Pennsylvania are allowed onlyone per year.

Utilities in Michigan are allowed relatively lowROCEs, while 100 percent of CWIP is allowed in therate base; both Florida and Pennsylvania allow’ above-average ROCEs, but Florida allows ‘‘varying’ amountsof CWIP in the rate base, while Pennsylvania includesonly small portions of CWIP. The remaining five Statesin the ‘ ‘highly vulnerable’ category rank so low in cur-rent emissions as to make the probable effect of addi-tional control requirements on their utility sectors quitesmall.

Utilities in an additional eight States are characterizedin table A-29 as having above-average rates of’ returnand relatively low bond ratings for 1980 (CO1. C), sug-


gesting potential concerns for long-term profitability. Six States are identified in table A-30 as having rela-Four of these States combine heavy reliance on coal- tively high bond ratings, but low rates of return, forfired plants with high average S02 emission rates from 1980. Of these, Indiana combines strong coal depend-these plants: Georgia (2.9 lb/MMBtu), Missouri (4.6), ency with a very high coal-fired, S02 emissions rate (4.2Ohio (3.9), and West Virginia (2.7). A fifth State, New lb/MMBtu), while Illinois has both moderate coal de-Hampshire, relies on oil-fired plants for more than half pendency and a relatively high emissions rate (3.1 lb/its generating capacity, and has an average oil-fired MMBtu).emissions rate of 2.1 lb/MMBtu.

Appendix B

Effects of Transported Pollutants

B.1 AQUATIC RESOURCES AT RISK (p. 207)B.2 TERRESTRIAL RESOURCES AT RISK (p. 217)B.3 MATERIALS AT RISK (p. 239)B.4 VISIBILITY IMPAIRMENT (p. 244)B.5 HUMAN HEALTH RISKS (p. 255)B.6 ECONOMIC SECTORS AT GREATEST RISK FROM CONTROLLING

OR NOT CONTROLLING TRANSPORTED POLLUTANTS (p. 261)

B. 1 AQUATIC RESOURCES AT RISK

Extent of Resources at Risk*

Scientists are concerned that acid deposition may bedamaging substantial numbers of U. S. and Canadianlakes and streams. As part of its assessment of trans-ported air pollutants, OTA contracted with The Insti-tute

●

●

●

●

of Ecology (TIE) to:describe mechanisms by which acid deposit ionmay be affecting sensitive 1akes and streams;providc an inventory of Eastern U.S. lakes andstreams considered to be sensitive to acid depo-sit ion;estimate the number of lakes and streams in thesescnsitive regions that have been affected and/oraltered by acidic deposition; andexamine three scenarios for future sulfate deposi-tion levels to the year 2000, and project effects onsensitive aquatic resources.

Because of’ scientific uncertainties and data limit a-tions, none of these tasks can be addressed at this timewith a high degree of accuracy. Each of’ these topics isthe subject of active research under the National AcidPrecipitation Assessment Program (NAPAP). To illus-trate, the estimates of the numbers of lakes and streamssensitive to acid deposition are based on eight separatewater quality surveys conducted at different times usingnonuniform procedures. NAPAP is currently planningto undertake a national survey-sampling several thou-sand water bodies over a much wider geographic area—to provide a more complete picture of the current mag-nitude of the problem.

——‘ [ his w f I( III J(l<ipt(.(j froril I ht. In\(i(ufv 0! K( I)IIJ<J ‘‘ R(.ql( )Il<il ,A\\t\\rl][n(

(J! ,i(l(ici[ II R(, \I 111 r( (,\ ,1[ R l\k I I I JIII A( I(li( I )t, pIJ\lI 1( III, ( ) 1 ,A ( ( IIIt I ,i( 1( II I {-,)( ,, I , 1‘IH.!

Because of the large area of a typical watershed, mostof the acid ultimately deposited in lakes and streamscomes from water that runs off or percolates throughthe surrounding land mass, rather than from precipita-tion falling directly on water bodies. The amount ofacidifying material that actually enters a given lake orstream is determined primarily by the soil and geologicconditions of the surrounding watershed. Whcn the twomajor chemical components of’ acid rain-nitric acid andsulfuric acid—reach the ground, they may react withsoils is a variety of ways. * * For example, soils can neu-tralize the acids, exchange nutrients and trace metalsfor components of the acids, and/or hold sulfuric acid.

Most soils contain amounts of counterbalancing (neu-tralizing) substances such as bicarbonate that may beavailable to ‘ ‘buffer” acid inputs. Such nutrients ascalcium and magnesium, when present in soils, may beleached by acidic deposition and enter water bodies,while acidity remains in the soil. When soils are highlyacidic, similar leaching of toxic metals such as alumi-num can occur, which may cause damage to aquatic lifein lakes and streams. In add it ion, the soils of somewatersheds are able to retain sulfuric acid to varyingdegrees. For these areas, deposited sulfuric acid will notpass into lakes and streams until the ‘ ‘adsorption”capacity ‘‘ of the soils is exceeded.

The extent to which such reactions actually occurdepends on a number of geologic and soil conditions.Where slopes are relatively steep, and soils are thin, lessopportunity exists for acid precipitation to infiltrate soil

‘ ● l;,)! { (]rrcn( ~ttcmpt\ (() ,i\s(~\ tht- rffc( ts of acid depositmn on aquat)[ m o-\, \tem\. sulfurlc ac Id If ( ons}dercd the Prlnc Ipal suhstam c of{ oncern ‘1’hc Inl-I N ) I (<trt( ( ( )f ,i(]]tosf]h(rl( ]n[){]l \ ()! t]ltrl( ‘i{ 1(1 (() ,i{{tI<tfl( f} ~lemi 1, $t)ll unt (r

t<iln Ix( ,I(IW f h( n II I I( ,i( I( I ( dn }N uw(~ ‘i\ d pltint nut rlvnl .Alt h( IU + III( I 1(,i( I(I (l<lx)\l(l(,rl rll<ik Ir)tlu(n{ f \lIr II)< .i( ldlti( ,it Ion ( (Icprvs.lon I)! })11 ) (l\]{. I(I>rl( )tt rllt,l[, II r~ LInl Ik(.l\ t( ) }]ci\ e ,111 ,ippf (( Icit)l(, (.11(. ( I ( II) tII ldsun)mcr ,i( 11111 \

207


layers and react chemically with soil components. Fur-ther, the composition of soils—the availability ofneutralizing material, exchangeable elements, or sulfuricacid adsorption capacity —also affects their overallability to mitigate acid deposition inputs to water bodies.Watersheds in a number of regions are believed to pro-vide aquatic resources with virtually complete protec-tion from current levels of acid deposition. In other re-gions, however, watersheds have little capacity toneutralize acidic substances, and much of the acid inprecipitation in these regions moves through the water-shed into lakes and streams.

Under unaltered conditions, virtually all lakes andstreams also have some acid-neutralizing capacities.Like soils, their waters contain such substances as bicar-bonate, which neutralize the entering acids. Alkalinitylevels, which are expressed in microequivalents perliter of water (µeq/1), measure the acid-neutralizingcapacity of lakes and streams. Lakes and streams definedas very sensitive to acidic inputs have alkalinity levelsof O to 40 µeq/1, while a lake with high capacity for acidneutralization can measure over 500 µeq/1. * If the sur-rounding watershed contains little neutralizing materi-al, natural alkalinity levels in lakes and streams maybe quite low, making these aquatic resources highly sen-sitive to even low levels of acidic inputs.

When acids enter a lake or stream, available neutral-izing substances are consumed, and alkalinity levels aredepressed. As water bodies become acidified, aquaticplant and animal populations may be altered. A lakeor stream is considered to be acidified when no neutraliz-ing capacity is left. Such bodies of water have beenmeasured as having negative alkalinity levels as greatas –100 µeq/1.

A multistep process was employed to develop an in-ventory of sensitive (but not necessarily altered) lakesand streams in the Eastern United States. TIE (adapt-ing a procedure developed by Oak Ridge National Lab-oratory) first used data on soil, watershed, and bedrockcharacteristics in 27 Eastern States to generate a list ofindividual counties whose freshwater resources werelikely to be sensitive to acidic deposition. The list ofcounties was then aggregated into 14 acid-sensitive re-gions (fig. B-l). Using U.S. Geological Survey maps,the contractor systematically sampled each region to esti-

“Reports by J. R. Kramer (3), H. Harvey, et al (4), and others have dl-\lded the spectrum of their sensitivity measure into a series of intervals referredtn as sensitlwty classes or categories Each approach differed slightly from theothers, Icadlng the authors of the U S -Canada Aquatlr Impacts AssessmentSubgroup (5) tu propose the fnllowing c]assiticatmn for lakes:(:ldss Alkallnltv (IU@)

I At dlfid < 011 F.xtremt- Scnsllll II} 0-’39

111 Nf[xk. ra[c scnw(lvltv 40.199I\’ IXM senstlliity 2oo-4wL’ Not wn\lt]\c 2500

Figure B-1.—Areas Sensitive to Acid Rain (shadedgrey)

Lake and stream sampling areas modified from Braun(1950) and Fenneman (1938). Region numbers correspondto those shown in table B-1.

mate its total number of lakes greater than 15 acres insize, and total miles of first- and second-order streams,**The results show an estimated 17,000 lakes and 117,000miles of first- and second-order streams in the 14 sen-sitive regions (table B-l).

Of this total number of lakes and streams in the sen-sitive regions, only a portion may be considered sen-sitive to acid inputs, Local variations in geology, soilconditions, and runoff patterns cause alkalinity levelsof lakes and streams within a sensitive region to rangefrom less than zero µeq/1 (acidified) to over 500 µeq/1(acid resistant). Regional water quality surveys*** wereused to estimate the percentage of the lakes and streamsin the 14 regions that can be considered sensitive to acid

● *The smallest unbranched tributary of a stream is a first-order stream; thejunction of two first-order streams produces a second-order stream segment,

* * “Eight surveys of lake and stream water quafity were used to evafuate theregional sensitivity of aquatic ecosystems to acid deposition. Regional estimatesare bawd on measurements from about 40 New England streams (6), 430Adirondack lakes (7), 45 Pennsylvania streams (8), 40 streams In North Caro-lina and Virglnla (9), 360 lakes in Wisconsin ( 10) and Minnesota (1 1), and40 W’lsconsm streams ( 12)

App. B—Effects of Transported Pollutants 209

Table B-1 .—Total Estimated Lake and Stream Resources in the Acid-SensitiveRegions of the Eastern United States (see fig. B-1)

Sensitive Total lakes Total streams (mi)

Region area (mi2) Number Acres 1st order 2d order

1.2.3.4.

5.6.7.

8.9.

10.11.12.

13.14.

Eastern Maine . . . . . . . . . . . . . . 26,398Western New England . . . . . . . 29,666Adirondacks . . . . . . . . . . . . . . . . 14,066East PennsylvaniaSouth New England. . . . . . . . . . 20,947West New York/Pennsylvania . 25,051Appalachian Plateau . . . . . . . . . 16,190Blue Ridge/Great SmokyMountains . . . . . . . . . . . . . . . . . . 20,964Coastal Plain . . . . . . . . . . . . . . . 9,264Lower Mississippi . . . . . . . . . . . 13,075lndiana/Kentucky . . . . . . . . . . . . 8,603Central Wisconsin . . . . . . . . . . . 12,141Wisconsin/MichiganHighlands . . . . . . . . . . . . . . . . . . 19,229Northeast Minnesota. . . . . . . . . 10,560Central Minnesota . . . . . . . . . . . 18,870

Totals . . . . . . . . . . . . . . . . . . . . . . 245.024

1,4251,5431,139

1,320376

13

126241170

9583

5,3071,6373,170

17.059

582,825763,785231,217

118,80016,92029,510

14,8688,917

56,610603

187,726

801,357473,093323,340

3.609.571

9,71415,3085,289

8,4007,1147,350

10,9011,5475,3742,8052,683

5,0371,6374,831

87,990

3,4854,5693,024

2,5561,6782,299

3,396713

1,255989728

1,737475

2.529

29,433SOURCE: “Regional Assessment of Aquatic Resources at Risk From Acidic Deposition, ” prepared for OTA by The Institute

of Ecology, June 1982

deposition, using a 200-µeq/1 alkalinity level as the cut-off point between sensitive and nonsensitive lakes andstreams. Results show an estimated 9,400 lakes and60,000 miles of streams that are currently sensitive tofurther acid inputs (tables B-2 and B-3).

To estimate the portion of these sensitive lakes andstreams that already have been altered by acidic depo-sition, TIE compared data on the distribution ofalkalinity levels for two distinct geographic areas: 1 ) re-gions with little neutralizing capacity that currently re-ceive high (resource-affecting) levels of acidic deposi-tion; and 2) geologically similar areas of northwesternOntario and northern Minnesota having little neutraliz-ing capacity, but that receive negligible amounts of aciddeposition. The difference between the two distributionsprovides an estimate of the proportion of lakes andstreams that can be considered ‘ ‘acid-altered, ratherthan simply sensitive. Only lakes with alkalinity levelsless than 40 µeq/1 and streams with less than 100 µeq/l—already acidified or extremely sensitive to furtheralteration—are considered in these calculations. Cal-culations using this approach show an estimated 3,000lakes and 23,000 miles of streams with alkalinity levelsthat can be described as already acid-altered. This cor-responds to 18 percent of the lakes and 20 percent ofthe streams located within the 14 sensitive areas (seetables B-4 and B-5).

Finally, TIE employed a simple model to estimate theeffects on aquatic resources of three possible future aciddeposition scenarios. As an underlying assumption, themodel uses an empirical measure to project changes inlake and stream alkalinities given a change in sulfate

deposition. This measure—the ‘ ‘alkalinity impact pa-rameter’ —is based on both limited observations ofalkalinity changes through time in areas where sulfatedeposition has been increased or reduced, and on cur-rent theory about the processes involved. * Although notyet fully tested, the model suggests that lake and streamalkalinities are likely to respond to future changes insulfate deposition. The model cannot address furtherchanges in lake and stream water quality that might oc-cur if deposition remains constant over the next sev-eral decades.

For scenario I, a 10-percent increase in sulfate depo-sition by 2000, the model projects that 5 to 15 percent(depending on the region) of the most sensitive lakesand streams worsen in condition— becoming either‘ ‘acidified’ or ‘ ‘extremely sensitive’ to acid inputs.

*An empiric al ‘‘alkalinity Impac I parame[cr’ (.~[~) can be clcfincd as thera[ io of obser\ cd changes in lake and stream alkalinity levels [c} changes insulfate loadings. W’hen sulfate retcntlon b\ the watershct] approa{ hes zer[~,n!tratt= uptake bv plants N h)~h, and for[her lossr~ of nu[rwrrt ( ,itt(m \—e y ,calclum and magnc~lum-ar-e low or negl]glble, acldlt}, ( H~S()+) direct l y a f -fects alkalinity (H(~OS), and the expected .41P IS ‘2 For the c asc in w h[ch w)menmstrafizatmr of acid input occurs in the watershed, the AIP mould be les~ than2. during the \,ery early stages of ac idic deposition. It should approa( h zeroWhere s{)ils ha\e high sulfate adsorption capa[ lty, the AIP WOU]d als(J approach

zero during the early stages of an acidification process, later. if ac Id deposition[o the w atershecl IS ciecreased, some of the sulfate prevmusly retained ( an bcwashed from thr sol]. and A[P values could exceed 2 Calculations using ,inAIP of greater than 2 were not (onsidered, since many of the watershmls Inthe re<qwrrs mapped as sensltl\re for this stud) ha\,e low sulfate adsorptionc apa[ Itle$

Thr- imp(]rtanc e of atmosphen( depnsltl{)n of calc Ium and maqneslum as po-tentldl neutrdflzlns aqents has been considered For the areas exarnmed, [ .d( lurnand maqnmlum dep(mltlon appear t[~ he on]} one-tenth the n~~~n[tude UI \ull,Itt,deposition. therefore, Its r[de has been t onsldered ne~llqlb]e for the present( alf ulattons.


Table B-2.-Estimated Lake Resources at Risk in the Acid-Sensitive Regionsof the Eastern United States

SensitiveRegion area (mi2)

1. Eastern Maine . . . . . . . . . . . . . . . . . . . 26,3982. Western New England . . . . . . . . . . . . 29,6663. Adirondacks . . . . . . . . . . . . . . . . . . . . . 14,0664. East Pennsylvania/

South New England. . . . . . . . . . . . . . . 20,9475. West New York/Pennsylvania . . . . . . 25,0516. Appalachian Plateau . . . . . . . . . . . . . . 16,1907. Blue Ridge/Great Smoky Mountains. 20,9648. Coastal Plain . . . . . . . . . . . . . . . . . . . . 9,2649. Lower Mississippi . . . . . . . . . . . . . . . . 13,075

10. Indiana/Kentucky . . . . . . . . . . . . . . . . . 8,60311. Central Wisconsin . . . . . . . . . . . . . . . . 12,14112. Wisconsin/Michigan Highlands . . . . . 19,22913. Northeast Minnesota. . . . . . . . . . . . . . 10,56014. Central Minnesota . . . . . . . . . . . . . . . . 18,870

Totals . . . . . . . . . . . . . . . . . . . . . . . . . . . 245,024

Percentage CalculatedTotal number of lakes number of

lakes <200 µeq/l lakes at risk

1,425 (80)a 1,1401,543 (80)a 1,2341,139 911

1,320376

13126241170

9583

5,3071,6373,170

17,059

(80)a

(80a

————

1,056301—

—.245

2,228786

1,5229,423

aIn the absence of other data, alkalinities from the Adirondacks have been ‘Seal.bNo estimate is being made for regions with fewer than 250 lakes.cIn the absence of other data, alkalinities from north Wisconsin have been ‘Seal

‘In the absence of other data, alkalinities from north Minnesota have been used.

SOURCE’ ‘(Regional Assessment of Aquatic Resources at Risk From Acidic Deposit ion,” prepared for OTA by The Instituteof Ecology, June 1982

Table B-3.—Estimated First- and Second-Order Stream Resources at Riskin the Acid-Sensitive Regions of the Eastern United States

Calculated totalPercentage miles of:

Sensitive Total streams (mi)Region

of stream 1 0 streams 2 0 s t r e a m sarea (mi2) 1st order 2d order <200 µeq/l at risk at risk

1. Eastern Maine . . . . . . . . . . . . . . . . . . . . . . . . . . . 26,398 9,714 3,485 81 7,868 2,8232. Western New England . . . . . . . . . . . . . . . . . . . . 29,666 15,308 4,569 56 8,573 2,5593. Adirondacks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14,066 5,289 3,024 (56)a 2,962 1,6934. East Pennsylvania/South New England . . . . . . 20,947 8,400 2,556 3,192 9715. West New York/Pennsylvania . . . . . . . . . . . . . . 25,051 7,114 1,678 61 4,340 1,0246. Appalachian Plateau . . . . . . . . . . . . . . . . . . . . . . 16,190 7,350 2,299 (61)b 4,484 1,4027. Blue Ridge/Great Smoky Mountains. . . . . . . . . 20,964 10,901 3,396 6,977 2,1738. Coastal Plain . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9,264 1,547 713 (43)C 665 3079. Lower Mississippi . . . . . . . . . . . . . . . . . . . . . . . . 13,075 5,374 1,255 (43)’ 2,311 540

10. Indiana/Kentucky . . . . . . . . . . . . . . . . . . . . . . . . . 8,603 2,805 989 (43)c 1,206 42511. Central Wisconsin . . . . . . . . . . . . . . . . . . . . . . . . 12,141 2,683 728 1,154 31312. Wisconsin/Michigan Highlands . . . . . . . . . . . . . 19,229 5,037 1,737 13 655 22613. Northeast Minnesota. . . . . . . . . . . . . . . . . . . . . . 10,560 1,637 475 (13)d 213 6214. Central Minnesota . . . . . . . . . . . . . . . . . . . . . . . . 18,870 4,831 2,529 (13)d 628 329

Totals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245,024 87,990 29,433 45,228 14,847aIn the absence of other data, alkalinities from west New England and west New York/Pennsylvania have been used.bln the absence of other data, alkalinities from west New York/Pennsylvania have been used.cIn the absence of other data, alkalinities from central Wisconsin have been used.

‘In the absence of other data, alkalinities from northern Wisconsin have been used,

SOURCE’ “Regional Assessment of Aquatic Resources at Risk From Acidic Deposition,” prepared for OTA by The Institute of Ecology, June 1982.

App. B—Effects of Transported Pollutants ● 211

Table B-4.—Estimates of Extremely Sensitive or Acidified Lake Resourcesa in the Eastern United States

1980 number Historic numberof lakes with of lakes with 1980 number of

Total number alkalinities alkalinities acid-altered lakesRegion of lakes <40 µeq/l <40 µeq/l <40 µeq/l

1. Eastern Maine . . . . . . . . . . . . . . . . . . . . . . . . . .2. Western New England . . . . . . . . . . . . . . . . . . .3. Adirondacks . . . . . . . . . . . . . . . . . . . . . . . . . . . .4. East Pennsylvania/

South New England . . . . . . . . . . . . . . . . . . . . .5. West New York/Pennsylvania . . . . . . . . . . . . .6. Appalachian Plateau . . . . . . . . . . . . . . . . . . . . .7. Blue Ridge/Great Smoky

Mountains. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8. Coastal Plain ., . . . . . . . . . . . . . . . . . ., . . . . . .9. Lower Mississippi . . . . . . . . . . . . . . . . . . . . . . .

10. lndiana/Kentucky . . . . . . . . . . . . . . . . . . . . . . . .11. Central Wisconsin . . . . . . . . . . . . . . . . . . . . . . .12. Wisconsin/Michigan

Highlands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13. Northeast Minnesota . . . . . . . . . . . . . . . . . . . .14. Central Minnesota. . . . . . . . . . . . . . . . . . . . . . .

Totals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1,4251,5431,139

456494456

434634

413448422

1,320376

13

423150

4011

383139——

126241170

9583

——

134

——

——

11717

5,3071,6373,170

17,059

1,2204995

1594995

1,06100

3,477 494 2,983Total number of Iakes altered, Class I and II 2,983.Percentage of lakes altered 18%.aLakes with alkalinity less than 40 µeq/l, based on using 1980 calculated alkalinity depression and “historic” area alkalinity distributions as a control

SOURCE’’Reglonal Assessment of Aquatic Resources at Risk From Acidic Deposition,” prepared for OTA by The lnstitute of Ecology, June 1982

Table B-5.—Estimates of Extremely Sensitive or Acidified Stream Resourcesa in the Eastern United States

Historic stream1980 miles with miles with Acid-altered

Total alkalinities alkalinities stream milesRegion stream miles <100 µeq/lb <100 µeq/l <100 µeq/l

1. Eastern Maine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2. Western New England . . . . . . . . . . . . . . . . . . . . . . . . . . . .3. Adirondacks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4. East Pennsylvania/South New England . . . . . . . . . . . . . .5.West New York/Pennsylvania . . . . . . . . . . . . . . . . . . . . . .6. Appalachian Plateau . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7.Blue Ridge/Great Smoky Mountains . . . . . . . . . . . . . . . .8. Coastal Plain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9. Lower Mississippi. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

10. lndiana/Kentucky. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11. Central Wisconsin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12. Wisconsin/Michigan Highlands . . . . . . . . . . . . . . . . . . . .13. Northeast Minnesota . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14. Central Minnesota . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

13,19919,8778,313

10,9568,7929,649

14,2972,2606,6293,7943,4116,7742,1127,360

117,423

3,7465,6413,0603,1093,2372,7384,058

4821,412

809726418130455

30,021

8161,228

514677543596884140410234211418131455

2,9304,4132,5462,4322,6942,1423,174

3421,002

575515

000

22,765Totals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7,257aStreams with alkalinity less than 100 µeq/l, based on 1980 calculated alkalinity depression and “historic” area alkalinity distributions as a control.

bA higher alkalinity level was used to denote extreme sensitivity for streams than for lakes

SOURCE “Regional Assessment of Aquatic Resources at Risk From Acidic Deposition,” prepared for OTA by The lnsttiute of Ecology, June 1982


Under scenario II, which provides for a 20-percent de-crease in sulfate deposition by 2000, 10 to 25 percentof the most sensitive lakes and streams are estimatedto experience some recovery —i. e., ‘ ‘acidified’ aquaticresources become ‘ ‘extremely sensitive’ or ‘ ‘extremelysensitive’ resources become ‘ ‘moderately sensitive.Scenario III, which involved a 35-percent decrease insulfate deposition by the year 2000, is estimated to re-sult in some recovery for 14 to 40 percent of the mostsensitive aquatic resources. *

Figures B-2 and B-3 summarize the projected effectsof scenarios I, II, and III on lakes and streams in a num-ber of the sensitive areas. Each bar graph illustratesscenarios 1, II, and III in that order. The two figuresshow the sum of the calculated shifts to or from themost sensitive resource categories, expressed as a per-cent of the total lake or stream resource in each area.The short, solid portion of each bar represents a highlyprobable response; the shaded portion of each bar rep-resents the upper bound of the probable response.

Scenario III (a 35-percent reduction in sulfate depo-sition by 2000) appears likely to result in relatively sig-nificant responses for the total resource. Recovery forlakes is projected to range from a few to about 30 per-cent in each area, and up to 20 percent for streams, withthe greatest recovery in areas of highest current depo-sition.

While the model indicates some important prospectsfor recovery, it cannot address certain long-term con-sequences of acidification. Soils that may have beendepleted of such nutrients as calcium and magnesiumby acid deposition might take a great deal longer to re-cover normal nutrient levels than water bodies take toregain equilibrium alkalinity levels. If the soil’s abilityto mitigate acid deposition recovers slowly, “acidshock ‘ ‘ episodes to water bodies from such events asspring snowmelt may persist for some time. The mag-nitude of such consequences is unpredictable at thistime.

Lastly, some discussion of the implications of theseresults for biological responses in aquatic systems is re-quired. Scientists are gradually developing an under-standing of how fish and other aquatic life are affectedby acid-induced alterations of their environments. Thus,predictive statements about changes in water qualityover some period of abatement represent the first stepin making predictive statements about the potentialrecovery of aquatic life.

“ Because the ‘1’lE model 1s most app]lcable to thnse lakes and s t r e a m s mthe w tcf-altered (Class 1 < 0 ~eq/1) and ex{rcmely sensitive (Class 11 0 to 40peq/1) c atcgorms, TIE used transfers into and out of each of these categormsas the measure of c han~e fur aquatic resuurces in response to altered depow -twn ‘1’o correct for diffa emes In Akalinlty dlstrlbutums bc.tweerr streams andlakes, a defined portmn of the streams In Class 111 (40 to 100 pcq/1) was m-( luded in the T1 F, c alc ulatlons

Figure B 2.—Lake Model Projections

,

Bar-graphs show the percent increase (or decrease) bythe year 2000 in lakes classed as “acidified” or“extreme” for the three deposition scenarios I (a 10-percent increase in deposition), II (a 20-percent decrease),and Ill (a 35-percent decrease), represented by the bars,in that order from left to right.SOURCE: “Regional Assessment of Aquatic Resources at Risk From Acidic

Deposition,” prepared for OTA by The Institute of Ecology, June 1982.

Effects of Acid Depositionon Aquatic Life

Losses of fish populations attributed to the effects ofacid deposition have received a great deal of public at-tention; however, the available evidence indicates thatacidic waters also affect many other forms of aquaticlife, from single-celled algae to large aquatic plants toamphibians such as frogs and salamanders. Adverse ef-fects on aquatic plants and animals can affect the avail-ability of food to other animals such as fish, aquaticbirds, and mammals.

Fish reproduction requires water pH levels of above4.5, according to numerous laboratory studies and fieldsurveys ( 13). The International Joint Commission hasrecommended a water quality standard of greater than


Figure B 3.—Stream Model Projections

I

(Where there is no black band, the lower bound is zero)

Bar-graphs show the percent increase (or decrease) by

the year 2000 in lakes classed as “acidified” or“extreme” for the three deposition scenarios I (a 10-percent increase in deposition), II (a 20-percent decrease),and Ill (a 35-percent decrease), represented by the bars,in that order from left to right.SOURCE “Regional Assessment of Aquatic Resources at Risk From Acidic

Deposition, ” prepared for OTA by The Institute of Ecology, June 1982.

pH 6.5 for successful fish reproduction. Death of adultfish does not generally occur until the pH is less than5.0. Rapid decreases in stream and lake pH due tospring snowmelt and release of acid accumulated overthe winter can be detrimental if they coincide with sen-sitive periods of the fish reproductive cycle. Severalreports have documented sudden fish kills in both riversand lakes associated with springtime pH depressions(14).

Survival of fish in water of low pH is influenced bytemperature, presence of metals such as aluminum,hardness of the water, and type of acid input. Alumi-num increases the sensitivity of fish to low pH levels(15). Increases in the concentration of aluminum arecorrelated with decreasing pH. Fish mortalities havebeen documented as a result of increased aluminum con-

centrations, increased acidity, and the combination ofthese two factors. The hardness of the water (mineralcontent) increases the ability of fish to withstand lowpH; fish communities disappear from soft waters athigher pH than they do from hard waters (16).

A recent inventory (1980)(17) of the New York StateAdirondacks (one of the largest sensitive lake districtsin the Eastern United States receiving significantamounts of acid deposition) indicates that the brooktrout fishery has been most severely affected by acidifica-tion. At least 180 former brook trout ponds in the Adir-ondacks will no longer support populations. A surveyof 214 Adirondacks lakes in 1975 revealed that 52 per-cent had surface pH levels below 5.0, and that 90 per-cent of these were entirely devoid of fish life. Some ofthese lakes had been surveyed between 1929 and 1937,when only 4 percent (or 10 lakes) were below pH 5.0and devoid of fish; over the intervening forty years en-tire fish communities of brook trout, lake trout, whitesucker, prawn bullhead, and several cyprinid specieswere eliminated (1 8).

Similar losses of fish species have been observed inacidic lakes in the La Cloche mountain range of On-tario, Canada ( 19). These field studies performed overtime show that species vary in their susceptibility to de-clining pH, and that the mechanisms by which individ-ual species are eliminated are complex. In Nova Scotiathere are nine rivers with pH less than 4.7 which previ-ously had salmon that can no longer sustain trout orsalmon reproduction (20). Losses to brook trout popula-tions in the Great Smoky Mountain National Park havealso been associated with the acidity of streams and alu-minum concentrations (21 ).

In the field, mass mortalities of fish have been ob-served during the spring due to the ‘‘acid shock’ fromhigh concentrations of pollutants in snowmelt. Elevatedconcentrations of aluminum mobilized from the soils bystrong acids present in snowmelt water are thought tobe a contributing factor to such large-scale fish mortality(22). Increases in juvenile salmon mortality in NovaScotia hatcheries have also been associated with snow-melt-induced pH depressions (23).

Field surveys and laboratory experiments have shownamphibian populations, such as frogs and salamanders,to be extremely sensitive to changes in pH. Many spe-cies breed in temporary pools that may be formed fromlow-pH meltwater in spring. Because of the great vul-nerability of their habitat to pH depressions, damageto amphibian populations may be one of the earliest con-sequences of acidification of freshwaters. Experimentshave shown correlations between pH and both mortalityand embryo deformity in frog and salamander popula-tions (24).

Numerous invertebrate animals are known to be af-fected by the acidification of water, although individual


species may vary greatly in sensitivity. Of these, shell-bearing organisms and molting crustaceans appear tobe the most sensitive to low pH (25). No molluscs areknown to inhabit waters of pH lower than 6.0, whilemost crustaceans (e. g., crayfish) are absent from watersof pH below 4.6 (26). Aquatic insects exhibit a widerange of sensitivities to pH (27).

Single-celled algae are a basic constituent of theaquatic food chain. Studies have shown that as pHdecreases, significant changes occur in the species anddiversity of algae that predominate (28). As lakes orstreams acidify, acid-tolerant algae proliferate (29). Thisgroup of algae is not readily edible by zooplankton, theanimals that link algae and smaller fish in the food chain.However, a recent study suggests that algal species havesome capability to adapt to acidic environments overthe long term. This may explain the observation thata group of relatively recently acidified lakes in Norwayhave less diverse algae than natural historically acidiclakes (30).

Changes in algae community structure induced byacidification may also alter zooplankton communitystructure. Acidification of lakes is accompanied bychanges in abundance, diversity, and seasonality ofzooplankton which may reflect changes in their foodbase (algae), predators (fish), and/or complex changesin water chemistry, Since both population density andaverage size of the animals are reduced, food availabil-ity to fish and other animals may be reduced (31).

Limited findings from New York State suggest thatacid-tolerant algae may cover submerged aquatic plantcommunities in acidic lakes, thereby preventing themfrom receiving the sunlight necessary for growth (32).Studies of Swedish lakes and preliminary informationfrom New York, Nova Scotia, and Ontario have shownthat acidification tends to cause decline of aquatic plantsand replacement by growths of sphagnum mosses onlake and river bottoms (33). Sphagnum moss creates aunique habitat which is considered unsuitable for somespecies of bottom-dwelling invertebrates or for use asfish spawning and nursery grounds (34). Densesphagnum beds may also reduce the appeal of freshwaterlakes and rivers for recreational activities.

A number of studies have also found that acidic watersare more favorable to fungi than to normal bacterialpopulations. In many Scandinavian lakes studied todate, an increase in bottom accumulation of organicmatter has been observed. This has been attributed toa shift in dominance from bacteria to fungi, which areless effective at decomposing organic material and whichdelay the recycling of nutrients (35).

Table B-6 and figure B-4 summarize the effects ofdecreasing pH on aquatic organisms. Table B-6describes biological processes affected in different orga-

Table B-6.-Effects of Decreasing pHon Aquatic Organisms

p H Effect

8.0-6.0

6.0-5.5

5.5-5.0

5.0-4.5

4.5 andbelow

In the long run, decreases of less than one-ha/fof a pH unit in the range of 8.0 to 6.0 are likelyto alter the biotic composition of lakes andstreams to some degree. However, thesignificance of these slight changes is notgreat.

Decreases of one-ha/f to one pH unit (a threefoldto tenfold increase in acidity) may detectablyalter community composition. Productivity ofcompeting organisms will vary. Some specieswill be eliminated.

Decreasing pH from 6.0 to 5.5 will reduce thenumber of species in lakes and streams.Among remaining species, significant altera-tions in the ability to withstand stress mayoccur. Reproduction of some salamander spe-cies is impaired,

Below pH 5.5, numbers and diversity of specieswill be reduced. Reproduction is impaired andmany species will be eliminated. Crustaceanzooplankton, phytoplankton, molluscs, amphi-pods, most mayfly species, and many stone flyspecies will begin to be eliminated. In contrast,several invertebrate species tolerant to low pHwill become abundant. Overall, invertebratebiomass will be greatly reduced. Certain higheraquatic plants will be eliminated.

Below pH 5.0, decomposition of organic detrituswill be impaired severely. Most fish specieswill be eliminated.

In addition to exacerbation of the abovechanges, many forms of algae will not surviveat a pH of less than 4.5.

SOURCE: International Joint Commission, Great Lakes Advisory Board (1979),after Hendrey, 1979.

nisms as the pH of water decreases. Figure B-4 displaysthe percent of each of 7 major categories (taxonomicgroups) remaining as pH decreases. For example, at pH7, 100 percent of normal mollusc species are present.As pH decreases, the number of species remainingdecreases rapidly. At a pH of 5.5, all mollusc specieshave disappeared.

B. 1 References

1 . Braun, E. 1 . . , Lkciduous F o r e s t s of L’as[ern i’Vorth

America (Philadelphia, Pa.: The Blakiston Co,, 19.tO).2. Fenncman, N. M., Ph~sio~raph) of’ the ~astcrn United

States (New York: McGraw-Hill Book Co., 1938),3. Kramer, J. R., ‘‘Geochemical and Lithological F’actors

in Acid Precipitation, USDA Forest Scr\icc’ GeneralTechnical Report NE-23, 1976.

4. Har\e}, H. H., Piercej R, C., Dillon, P. J., Kramer,J. P., and W’helpdale, D. M., ‘ ‘Acidification in the Cana-dian Aquatic En\’ironment: Scientific C ritcrion fbr Assess-ing I+; f-fkcts of Acidic I>epos it ion on Aquatic Ecosystems

—

App. B—Effects of Transported Pollutants ● 2 1 5

Figure B-4.— Relative Number of Taxa of the MajorTaxonomic Groups as a Function of Acidity

75

5025

75

5025

75

5025

75

50

25

75

5025

75

5025

75

5025

L

-W Insects-

-- MolkIscs-

-- Sponges

-- Leeches-

-- Zooplankton

F Fish

/“

1= II , I I I

2 3 4 5 6 7

pH

SOURCE Impact Assessment, Work Group 1, United States ~ Canada Memoran.dum of Intent on Transboundary Air Poll utlon, Final Report, January1983

(Ottawa, Ontario, Canada: National Research CouncilCanada, NRCC No. 18475, 1981).

5. U.S.-Canada Memorandum of Intent on TransboundaryAir Pollution, ‘ ‘Impact Assessment, Work Group I,Phase II Interim Working Paper (Washington, D. C., andOttawa, Ontario, Canada, 1981).

6. Haines, T. A., ‘‘ Effects of Acid Rain on Atlantic SalmonRi\’ers and Restoration Efforts in the United States, Pro-ceedings of the Conference on Acid Rain and the Atlan-tic Salmon, Portland Maine, IVovember 22-23, 1980, In-ternational Atlantic Salmon Foundation SpecialPublication Series No. 10, March 1981 (New York: IASF,1981 ).

7. Pfeiffer, M. H., and Festa, P. J., “Acidity Status of Lakesin the Adirondack Region of New York in Relation to FishResources. Progress Report’ (Albany, N. Y.: New YorkState Department of Environmental Consem’ation, 1980).

8. Arnold, D. E., ‘ ‘vulnerability of Lakes and Streams inthe Middle Atlantic States to Acidification, Interim Prog-

9.

10.

11

12

13.

14

15

16

17

18

19,

ress Report (Uni\’ersit}’ Park, Pa. : Cooperat it’e FisheriesResearch Unit, Penns~l\ania State Uni\ersit~’, 1981).Hendrey, G. R., Gal]owa}, J. N., Norton, S. A., Scho-field, C. L., Shaffcr, P. W’., and Burns, D. A., ‘ ‘Geolog-ical and H}’drochernical Sensitivity’ of the Eastern UnitedStates to Acid Precipitation” (Comailis, Oreg.: U.S. EP.4En\’ironmental Research Lab, EPA-600/3-80-024, 1980).Eilers, J. (with 12 other authors), “Acid Precipitation In-\restigation for Northern W’ isconsin, Progress Report(Duluth, Minn.: Wisconsin DNR, Rhinelander; and U.S.EPA-ERL, 1979).Glass, G. E., and Loucks, O. L. (ecis. ), ‘ ‘Impacts of Air-borne Pollutants on k$’ilderness Areas Along the ~finne-sota-Ontario B o r d e r , EPA-600/3-80-044 (Duluth,N4inn.: U.S. EPA En\ironrnental Research Lab, 1980).Andrews, L. M., and Thrcintm, C. W’., ‘‘Surface WaterResources of Oneida Count?. ’ (hladison, Wis.: Wiscons-in Conservation Department Report, 1966); and Klick,T. A., and Threinen, C. W., ‘‘Surface Water Resourcesof Jackson County, Lake and Stream Classification Proj-ect’ (Madison, Wis.: Department of Natural Resources,1968).Beamish, R. J., “Acidification of Lakes in Canada by AcidPrecipitation and the Resulting Effects on Fishes, ll’a-ter, Air, Soil Pollut. 6:50 1-514, 1976; and EIFAC (Euro-pean Inland Fisheries Ad\isor?’ Commission), “WaterQuality Criteria for Freshwater Fish, Report on ExtremepH Values and Inland Fisheries, Water Res. 3 :593-61 1,1969.Har\e), H. H., “The Acid Deposition Problem andEmerging Research Needs in the Toxicology of Fishes,Proc. 5th Annual Aquatic Toxicity Workshop, Hamilton,Ontario, No\T. 7-9, 1978, Fish. Afar. Ser\. Tech. Rep.862:1 15-128, 1979.Davis, J. M., External Re\icnv Draft, Research TrianglePark, N. C., U.S. Environmental Criteria and AssessmentOffice, 1980; and Dickson, W., ‘ ‘Some Effects of theAcidification of Swedish Lakes, \ ‘erh. Znt. Ircrein. L.im-noi, 20:851 -856, 1978.Lei\’estad, H., Hendrcy, G., Muniz, I. P., and Snek\’ik,E,, ‘ ‘Effects of Acid Precipitation on Freshwater Orga-nisms, Impact of’ Acid Precipitation on Forest andFreshwater Ecosystems in Norway, F. Braekke (ed. ),SNSF Project, NISK 1432 Aas-NLH, Norway, 1976.Pfeiffer, M. H., and Festa, P. J., “Acidity Status of Lakesin the Adirondack Region of New York in Relation to FishResources, Progress Report, Department of Environ-mental Conservation, New York State, Albany, 1980.Schofield, C. L., “Lake Acidification in the AdirondackMountains of New York: Causes and Consequences, ”Proc. 1st Int. Symp. on Acid Precipitation and the For-est Ecos)’s[em, USDA Forest Ser\’ice General TechnicalReport NE-23, 477, 1976.Beamish, R. J., ‘ ‘The Loss of Fish Populations FromUnexploited Remote Lakes in Ontario, Canada, as a Con-sequence of Atmospheric Fallout of Acid, Water Res.8:85-95, 1974; Beamish, R. J., “Acidification of Lakesin Canada by Acid Precipitation and the Resulting Ef’-fects on Fishes, V1’ater, Air, Soil Pollut. 6:501 -514, 1976;

99-413 0 - 84 - 15 : QL. 3


20.

21.

22.

23

24

25.

26.

27

28.

and Beamish, R. J., and Harvey, H. H., ‘ ‘Acidificationof the La Cloche Mountain Lakes, Ontario and ResultingFish Mortalities, ’)J. Fish. Res. Bozud Can. 29:1 131-1143,1972.Watt, W. D., ‘ ‘Present and Potential Effects of Acid Pre-cipitation on the Atlantic Salmon in Eastern Canada,Acid Rain and the Atlantic Salmon, Special PublicationsSeries of the International Atlantic Salmon Foundation,No. 10, 1981.Herrmann, R., and Baron, J., “Aluminum Mobilizationin Acid Stream Environments, Great Smoky MountainsNational Park, U. S.A., ” Proc. Int. Conf. Ecol. Impactof Acid Precipitation, D. Drablos and A. Tollan (eds. ),SNSF Project, Norway, 1980.Muniz, I. P., and Leivestad, H,, “Acidification—Effectson Freshwater Fish, ” Proc. Int. Conl Ecological ImpactAcid Precipitation, D. Drablos and A. Tollan (eds.), SNSFProject, Norway, 1980; and Schofield, C. L., and Troj-nar, J. R., “Aluminum Toxicity to Brook Trout (Salve-linus fontinalis) in Acidified Waters, Polluted Rain (NewYork: Plenum Press, 1980).Farmer, G. J., Goff, T. T., Ashfield, D., and Samant,H. S., “Some Effects of the Acidification of AtlanticSalmon Rivers in Nova Scotia, ” Can. Tech. Rep. Fish.Aquat. Sci., No. 972, 1980.Pough, F. H., ‘ ‘Acid Precipitation and Embryonic Mor-tality of Spotted Salamanders, Ambystoma Mact.datum,Science 192:68-70, 1976; and Stirjbosch, H., “HabitatSelection of Amphibians During Their Aquatic Phase, ”Oikos 33:363-372, 1979.Okland, K. A., “Ecology and Distribution of AcellusAquaticus (L) in Norway, Including Relation to Acidifica-tion in Lakes, ” SNSF Project, IR 52/80, 1432 Aas-NLH,Norway, 1980; and Wiederholm, T., and Eriksson, L.,‘‘Benthos of an Acid Lake, ” Odcos 29:261-267, 1977.Okland, J., “Om Fursuring av Vassdrag og Betydningenav Surhetsgraden (pH) for Fiskens Naeringsdyr: Fersk-vann, ” Fauna 22: 140-147, 1969; and Svardson, G., “In-form. Inst. Freshw. Res. Drottingholm’ (Cited in Almer,et al., 1978), 1974.Almer, B., Dickson, W., Ekstrom, C., and Hornstrom,E., “Sulfur Pollution and the Aquatic Ecosystem, ” Sulfurin the Environment: Part II Ecological Impacts, J. O.Nriagu (cd. ) (New York: John Wiley & Sons, Inc., 1978),Kwiatkowski, R. E., and Roff, J. C., “Effects of Acidityon Phytoplankton and Primary Production of SelectedNorthern Ontario Lakes, ” Can, J. not. 54:2546-2561,1976.

29. Dickson, W., “Some Effects of the Acidification of Swed-ish Lakes, ” Verh. Int. Verein. Limnol, 20:851-856, 1978;and Yan, N. D., “Phytoplankton of an Acidified, Heavy

30

31

32

33

34,

35.

Metal-contaminated Lake Near Sudbury, Ontario, 1973-1977, ” Wat. Air Soil Pollut. 11 :43-55, 1979.Raddum, G. G., Hobaek, A,, Lomsland, E. R., andJohnson, T., “Phytoplankton and Zooplankton in Acid-ified Lakes in South Norway, Ecol. Impact of Acid?+ecipitation, D. Drablos and A. Tollan (eds. ), SNSFProject, Norway, 1980.Yan, N. D., and Strus, R., “Crustacean ZooplanktonCommunities of Acidic, Metal-contaminated Lakes NearSudbury, Ontario, ” Ont. Min. Env. Tech. Rep., LTS79-4, 1979.Hendrey, G. R., and Vertucci, F., “Benthic Plant Com-munities in Acidic Lake Colden, New York: Sphagnumand the Algal Mat, Proc. Int. Conf Ecological ImpactAcid Precipitation, D. Drablos and A. Tollan (eds. ), SNSFProject, Norway, 1980.Harvey, H. H., Pierce, R. C., Dillon, P. J., Kramer,J. P., and Whelpdale, D. M., Acidification in the Cana-dian Aquatic Environment: Scientific Criterion for anAssessment of the Effects of Acidic Deposition on AquaticEcosystems, Nat. Res. Coun. Canada Report No. 18475,1981; Hendrey, G. R., and Wright, R. F., “Acid Pre-cipitation in Norway: Effects on Aquatic Fauna, Proc.1st Spec. Symp. on Atmospheric Contribution to theChemistry of Lake Waters, Int. Assoc. Great Lakes Res.,Orillia, Ontario, Sept. 28-Oct. 1, 1975, J. Great LakesRes. 2, Suppl. 1: 192-207, 1976; Kerekes, J. J., “Sum-mary of the 1980 Environmental Contaminants ControlFund Investigation in the Calibrated Watersheds Studyin Kejmkujik National Park, unpublished manuscript,Canadian Wildlife Service, Halifax, Nova Scotia, 1981;and Grahn, O., “Macrophyte Succession in SwedishLakes Caused by Deposition of Airborne Acid Sub-stances, Proceedings of the First International Sym-posium on Acid Precipitation and the Forest Ecosystem,L. S. Dochinger and T. A. Seliga (eds. ), Ohio StateUniversity, May 12-15, 1975, USDA Forest ServiceGeneral Technical Report NE-23, Upper Darby, Pa., For-est Service, U.S. Department of Agriculture, NortheasternForest Experiment Station, 1976.Hultberg, H., and Grahn, 0,, ‘ ‘Effects of Acid Precipita-tion on Macrophytes in Oligotrophic Swedish Lakes,Proc. First. Specialty Symposium on Atmospheric Con-tribution to the Chemistry of Lake Waters, Internat.Assoc. Great Lakes Res. Sept. 28-Oct. 1, 1975.Bick, H., and Drews, E. F., ‘ ‘Self Purification and SilicateCommunities in an Acid Milieu (Model Experiments), ’Hydrobiologia 42:393-402, 1973; and Traaen, T. S., andLaake, M., ‘ ‘Microbial Decomposition and CommunityStructure as Related to Acidity of Fresh Waters—An Ex-perimental Approach, SNSF Project, Norway, 1980.

App. B—Effects of Transported Pollutants . 217

B.2 TERRESTRIAL RESOURCES AT RISK*

The Effects of Ozone onAgricultural Productivity

For over two decades, ozone has been known to harmcrops (27). * * Alone, or in combination with sulfur di-oxide (S02) and nitrogen oxides (NOX), it causes up to90 percent of the Nation’s air pollution-related croplosses (29). Previous studies estimated that 2 to 4 per-cent of total U.S. crop production was lost annually,using limited available data and assuming that all areasof the United States just met the current ozone stand-ard. These efforts were limited by the unavailability offield-generated data on crop loss, insufficient data onozone levels in various parts of the country, and a lackof integration with available crop distribution and pro-ductivity data.

OTA’s analysis uses National Crop Loss AssessmentNetwork (NCLAN) field-experiment data on the effectsof ozone on crops (28), in combination with more re-cent crop and ozone data, to estimate the effects of ozoneon U.S. corn, wheat, soybean, and peanut production.

The selected crops range in susceptibility to ozonefrom sensitive (peanut) to sensitive/intermediate (soy-bean) to intermediate (wheat) to tolerant (corn). Amongmajor U.S. agricultural commodities, these four cropsrepresent 62 percent of the acres harvested and 63.5 per-cent of the dollar value. The analysis compared county-level agricultural data with estimated county-level non-urban ozone concentrations derived from measurementsat approximately 300 selected monitoring stations. Ac-tual 1978 crop yields were assumed to represent poten-tial yields minus reductions in productivity due to cur-rent levels of atmospheric pollutants including ozone.Data from controlled field experiments were used to de-velop dose-response functions relating ozone level tocrop productivity. The functions were then used to es-timate potential gains in productivity achievable by re-ducing ozone levels to an estimated natural “back-ground” concentration of 25 parts per billion (ppb).

The assessment estimates that in 1978, corn yieldswould have increased by 2.5 percent, wheat by 6 per-cent, soybeans by 13 percent, and peanuts by 24 per-cent if ozone levels had been reduced to natural back-ground levels. As measured by 1978 crop prices, thisrepresents about $2 billion of agricultural productivity.

‘This sectmn adapted from O a k R]dge JNatlonal I,aboratory, Enwronmen-taf Sciences Division, ‘ ‘An Analysls of Potential Agriculture and Forest Im-pacts of Long-Range Transport Alr Pollutants, ” C)”I’A contractor report, 1983,

● “Cltatlon numbers are keyed to Reference Ilst at back of this sectmn

Of the estimated dollar impact, soybeans represent 69percent, corn 17 percent, wheat 6 percent, and peanuts8 percent. The Corn Belt States of Illinois, Iowa, andIndiana, plus Missouri, Arkansas, Minnesota, Ohio,Kentucky, North Carolina, and Virginia were estimatedto have experienced the greatest agricultural effect.

Crop Response Data

Crop response data were obtained from the 1980NCLAN Annual Report (77), or from earlier experi-ments using the methods later adopted for the NC LANproject (22,24,25). Test plants were grown in uniform,open-top field chambers and exposed to carefully con-trolled ozone levels. Yield data from plants receivingcharcoal-filtered air (25 ppb ozone) were used as con-trols. Three sets of soybean data, four sets of wheat data,and one set each for corn and peanuts were used to es-timate quantitative relationships between ozone levelsand crop damage.

Crop Yield Data

The Census of Agriculture, conducted approximatelyevery 5 years by the Department of Commerce, devel-ops an extensive national inventory based on responsesto mail questionnaires. The 1978 Census of Agricultureprovided county-level yield statistics for the surveyedcrops. The analysis averaged winter and spring wheatyields together, and excluded sweet corn productionfrom corn yields.

Ozone Data

The U.S. Environmental Protection Agency (EPA)provided estimates of seasonal ozone concentrations forthe analysis (75). EPA selected approximately 300 froma total of over 500 EPA monitoring stations as regionallyrepresentative and free from urban influence. Stationsand observations were screened to eliminate those withfew or unrepresentative readings. The monitoring sta-tions are irregularly distributed, and large areas of thecountry lack monitoring data for rural areas. The avail-able data were used to estimate values for counties with-out monitoring data using a statistical-averaging pro-cedure called kriging. Seasonal averages were calculatedas the mean of the growing season months appropriatefor each crop (wheat, April-May; corn, peanuts, June-August; and soybeans, June-September). The EPA esti-mates of average ozone concentration during June toSeptember 1978 are show in chapter 4 (fig. 15).


Regional Impacts

Figures B-5 through B-8 show the general pattern ofproductivity gains for each crop as potential yield in-creases (i. e., bushels/acre). Table B-7 summarizes theseyield increases (as percentage increases), and their mar-ket value at 1978 average crop prices, by State. How-ever, these dollar values do not reflect the potential priceeffect of the projected yield increases. Since increasingcrop production would tend to lower crop prices, thedollar values in table B-7 should only be considered asurrogate for ozone-related crop damage; the dollar val-ues allow comparisons of yield increases across all fourcrops, as well as comparisons of potential State-level pro-ductivity increases.

Projections of Economic Effects If Ozone LevelsAre Reduced in the Future

If ozone levels are reduced, the cost of producing anozone-sensitive crop will decrease, because the sameamount of land, fertilizer, labor, etc., will result ingreater crop yields. But the economic effects of reduc-ing ozone levels also depend on how farmers and con-sumers react to these changes. Farmers could, for ex-ample, choose to grow the same amounts of these cropsas before, reducing their inputs of land, fertilizer, andlabor. Alternatively, they could increase their produc-tion, making greater crop supplies available in the mar-ketplace, though presumably at somewhat reduced cropprices.

Analysts at the U.S. Department of Agriculture(USDA) used two econometric models to estimate howOTA’s projected yield increases might affect farmersand consumers (80). The models assessed the potentialeffect of eliminating half the manmade ozone over a 10-year period (i.e., reducing ozone concentrations to themidpoint between measured 1978 levels and the esti-mated natural background level of 25 ppb by the early1990’s).

One of the models focuses primarily on domestic agri-cultural trends and policies; it projected that increasingthe productivity of these three crops would cause sup-plies to increase moderately. However, it also projectedthese increases to cause proportionately larger declinesin crop prices, reducing net farm income significantly,while inducing only marginal declines in the ConsumerPrice Index for food. The second model was designedprimarily to assess international trends in agriculturalproduction. While it also projected a moderate increasein U.S. supplies of corn, wheat, and soybeans, changesin production levels had significantly different economicrepercussions. Estimated price reductions and supplyincreases were approximately in balance; supply in-creases outweighed price declines for corn and soybeans,

while price declines were proportionately larger thansupply increases for wheat. Gross farm receipts for thethree crops overall were estimated to increase slightly.The two models provide a qualitative perspective on thecomplex relationship between pollution and the agricul-tural sector of the economy; the economic effect of po-tential ozone reductions depends heavily on both farmerresponse and Federal agricultural policy.

Effects of Acid Rain onAgricultural Crops

Because several major U.S. agricultural regions ex-perience elevated levels of acid deposition, researchersare attempting to determine whether acid deposition af-fects crop productivity. Crops are more likely to be dam-aged through direct contact with acid deposition onaboveground portions of plants than through soil-relatedeffects. However, some soil-mediated effects—e.g.,changes in nutrient availability, microbial activity, ormetal toxicity—might also be important.

Research on how acid deposition affects crops has ad-vanced about as far as research on ozone effects in thelate 1960’s. Acid deposition is a mixture of chemicals;plants respond not only to the hydrogen ions (acidity)but also to sulfate and nitrate ions that can act as ferti-lizers. Moreover, some researchers hypothesize interac-tions with other physical and biotic causes of plant stress(e. g., air pollution and pests), but little definitive evi-dence exists on which to base conclusions.

Mechanisms of Acid Rain Effect on Vegetation

No direct, visible injury to vegetation in the field hasbeen demonstrated to result from exposure to ambientacid deposition. Rather, information about effects comesfrom a wide variety of approaches involving, in mostinstances, some form of rain ‘‘simulation. Adding sul-fate and nitrate to soil-plant systems can have both pos-itive and negative effects. Each system’s response is af-fected by: 1) precedent conditions (e. g., soil nutrientstatus, plant nutrient requirements, plant sensitivity,and growth stage); and 2) the total loading or deposi-tion of the critical ions (nitrate, sulfate, and hydrogenions).

Concentrations of hydrogen ions equivalent to thosemeasured in highly acidic rainfall events (i. e., pH lessthan about 3), have caused tissue lesions on a wide vari-ety of plant species in greenhouse and laboratory ex-periments. This visible injury is reported to occur at athreshold of between pH 2.0 and 3.6. No evidence atthe present time suggests that hydrogen ion inputs haveany beneficial effect.


Table B-7.— Estimated Crop Gains (percentage increase and millions of 1978 dollars) Due to OzoneReduction—Based on 1978 Crop and Ozone Data

Wheat Corn Soybeans Peanuts

Percent Millions Percent Millions Percent Millions Percent Millionsincrease of dollars increase of dollars increase of dollars increase of dollars

Alabama . . . . . . . . . . . . . . .Alaska . . . . . . . . . . . . . . . . .Arizona . . . . . . . . . . . . . . . .Arkansas. . . . . . . . . . . . . . .California . . . . . . . . . . . . . .Colorado . . . . . . . . . . . . . . .Connecticut . . . . . . . . . . . .Delaware. . . . . . . . . . . . . . .Florida. . . . . . . . . . . . . . . . .Georgia . . . . . . . . . . . . . . . .Hawaii . . . . . . . . . . . . . . . . .Idaho . . . . . . . . . . . . . . . . . .Illinois . . . . . . . . . . . . . . . . .Indiana . . . . . . . . . . . . . . . .Iowa. . . . . . . . . . . . . . . . . . .Kansas . . . . . . . . . . . . . . . .Kentucky . . . . . . . . . . . . . .Louisiana . . . . . . . . . . . . . .Maine . . . . . . . . . . . . . . . . .Maryland . . . . . . . . . . . . . . .Massachusetts . . . . . . . . .Michigan . . . . . . . . . . . . . . .Minnesota . . . . . . . . . . . . .Mississippi . . . . . . . . . . . . .Missouri . . . . . . . . . . . . . . .Montana . . . . . . . . . . . . . . .Nebraska . . . . . . . . . . . . . .Nevada . . . . . . . . . . . . . . . .New Hampshire . . . . . . . . .New Jersey . . . . . . . . . . . .New Mexico . . . . . . . . . . . .New York . . . . . . . . . . . . . .North Carolina . . . . . . . . . .North Dakota . . . . . . . . . . .Ohio . . . . . . . . . . . . . . . . . .Oklahoma . . . . . . . . . . . . . .Oregon . . . . . . . . . . . . . . . .Pennsylvania . . . . . . . . . . .Rhode Island . . . . . . . . . . .South Carolina . . . . . . . . . .South Dakota . . . . . . . . . . .Tennessee . . . . . . . . . . . . .Texas . . . . . . . . . . . . . . . . . .Utah . . . . . . . . . . . . . . . . . . .Vermont . . . . . . . . . . . . . . .Virginia . . . . . . . . . . . . . . . .Washington . . . . . . . . . . . .West Virginia . . . . . . . . . . .Wisconsin . . . . . . . . . . . . .Wyoming . . . . . . . . . . . . . .

United States.. . . . . . . .

8.0——5.6—7.6—2.0—8.0——5.35.25.94.83.77.3—2.0—4.04.96.74.50.96.26.3—3.0

10.25.57.25.34.64.71.55.60.08.35.44.97.37.8—3.21.93.96.67.55.3

———

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517

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1125

2.7——4.52.33.00.03.01.22.7——2.63.02.32.82.42.3—3.4—1.61.13.72.7—2.1——1.93.62.14.10.72.83.0—2.5—

4.11.32.92.93.7—3.6—2.12.33.02.4

1———

25

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715

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210

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13,013.711.39.9

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14.1—6.39.6

18.012.7—8.4——9.4——

20.6—

12.117.9—

10.10.0

21.78.1

13.211.5——

19.1——

12.0—

28——132—

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173054

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7689

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976

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64312

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1,485

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14.922.3——————————————————————

35.9——

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23.8

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572——————————————————————34——10

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175SOURCE: Oak Ridge National Laboratory, 1983.


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Recent research has found that vegetation is ex-tremely responsive to the sulfur and nitrogen inputs inacid precipitation. Evidence from studies of field-grownsoybeans (34) and forest tree species (2, 119) indicate anapparent positive growth response to the sulfur and ni-trogen in simulated acid rain. Other work suggests thatsulfur may have been a limiting factor in the nutritionof experimental lettuce plots (37).

Pollutant deposition theoretically could affect soil-plant systems over the long term through potential soilchanges— e.g., 10SS of calcium and magnesium or re-lease of toxic metals. However, since croplands areheavily managed and fertilized, such soil-related effectsdue to acid deposition are unlikely.

Results of Field and Laboratory Studies

Several investigators have performed dose-responseexperiments on a variety of plant species. Thresholdsfor direct, visible injury to greenhouse foliage subjectedto simulated acid rain typically are about pH 3.1 (36).However, field trials using the same treatment solutionsunder both greenhouse and field situations yield signif-icantly different estimates of species sensitivity.

Experimental evidence suggests that a plant’s‘‘wetability’ is an important factor in its response toacid deposition. Comparisons between studies of rela-tively wetable, nonwaxy bean cultivars (19,38,83) andstudies of very waxy citrus leaves (26) show that the beancultivars have a threshold of between pH 3.1 and 3.5for developing foliar lesions, while a greater than 400-times increase in hydrogen ion concentration—to nearpH 2.0—is required to induce visible symptoms in thecitrus leaves. Waxy leaves appear to minimize the con-tact time for acid solutions. Table B-8 summarizes re-sults of field experiments that applied simulated acid rainto nine crops: alfalfa, beet, corn, fescue, kidney bean,mustard green, radish, soybean, and spinach. The tablelists effects on crop growth or yield rather than visibleinjury. No consistent trends are observed. For exam-ple, experiments on different types of soybeans resultedin positive, negative, and no growth effects. For bothalfalfa and mustard green, altering the chemical com-position of the acid rain simulant (but keeping the pHconstant) drastically altered experimental results. Fur-ther complicating interpretation of these data, researchhas shown that the experimental procedures used toapply acid rain simulants also can affect results (18).

To summarize available information on how acid dep-osition affects crops: 1 ) visible injury thresholds for acidprecipitation lie between pH 2.0 and 3.6, depending onspecies, and may vary from pH 3.0 to 3.6 within thesame species (e. g., bean); 2) total dose of hydrogen ionsappears to be most clearly related to visible injury; and3) growth effects in the absence of visible injury have

been reported at a threshold of between pH 3.5 and 4.0,but sulfur and nitrogen in the precipitation may causepositive net growth effects, depending on soil nutrientstatus, buffering capacity, other growth conditions, andplant nutrient requirements.

Relationship of Acid Rain to Overall CropDamage From Pollutants

Because acid deposition occurs throughout the East-ern United States and Canada, vegetation is commonlyexposed both to gaseous pollutants such as ozone andsulfur dioxide, and to wet deposition of acidic sub-stances. Little information is available to evaluate howplants respond to the combined effects of wet- and dry-deposited pollutants.

The foliage of vegetation is wetted by rain, fog, ordew formation during significant portions of the grow-ing season in midlatitude temperate climates. Duringthese periods, leaf surfaces more readily take up dry-deposited gases. For example, researchers found thatas S02 dissolved in the dew on leaf surfaces, the acidityof the dew increased, suggesting the potential for dry-deposited acidic pollutants to react directly with wetvegetation surfaces ( 103).

Preliminary work suggests that acid deposition mayinteract with other pollutants. One researcher observeda significant growth reduction at harvest in plants in-termittently exposed to ozone in addition to receivingfour weekly exposures to rainfall of pH 4.0 (85). Anotherdemonstrated that ozone depresses both growth andyield of soybeans under three different acid rain treat-ments, and that the depression was greatest with themost acidic rain (36). Experiments on field-grown soy-beans found that simulated acid precipitation (pH 3.1)appeared to lessen plant response to S02 (34). Themechanisms of interaction are currently under investiga-tion, but unknown.

Effects of Multiple Pollutantson Forests

One-third of the total land area of the United Statesis forested; two-thirds of that area—approximately 400million acres—is classed as commercial timberland.Nearly three-quarters of the country’s commercial tim-berland is located in the Eastern United States, dis-tributed about equally between the North and South sec-tions (fig. B-9). Nearly 80 percent of New England, andgreater than 40 percent of the Atlantic Coast States, areforested.

Scientists have recently discovered productivity de-clines in several tree species throughout the EasternUnited States from New England to Georgia. Acid dep-


Table B-8.—Field Research on Effects of Acid Precipitation on Crop Growth and Yield

Species/variety Test pH As compared to: Effect

Alfalfa . . . . . . . . . . . . . . . . . . . . 3.0, 3.5,4.0a

Beet . . . . . . . . . . . . . . . . . . . . . 2.7, 3.1, 4.05.7

Corn . . . . . . . . . . . . . . . . . . . . . 3.0, 3.54.0

Fescue . . . . . . . . . . . . . . . . . . . 3.03.5,4.0

Kidney bean . . . . . . . . . . . . . . . 3.2Mustard green . . . . . . . . . . . . . 3.0a, 4.0a

3.5Radish ’’Champion’’ . . . . . . . . 2.8

3.54,25.6

Radish “Cherry Belle” . . . . . . 3.0,4.03.5a

Radish “Cherry Belle” . . . . . . 2.7, 3.1, 4.0Soybean “Amsoy” . . . . . . . . . 2.3

2.73.1, 4.0

Soybean “Amsoy” b. . . . . . . . . 2.7a

3.3a

4.1a

Soy bean ’’Benson’’ . . . . . . . . . 2.83.4

Soybean “Davis”. . . . . . . . . . . 2.8, 3.2, 4.02.4, 3.2, 4.1

Soybean “Wells” . . . . . . . . . . 3.065.6

Soybean “Williams” . . . . . . . . 2.83.4

Spinach . . . . . . . . . . . . . . . . . . 3.0, 3.5, 4.0

Control: 5.6Control: 5.6Ambient: 4.06Ambient: 4.06

Control: 5.6Control: 5.6Control: 5.6Control: 5.6Control: 6.0Control: 5.6Control: 5.6Control: 5.6Control: 5.6Control: 5.6Ambient: 3.8Control: 5.6Control: 5.6Control: 5.7Ambient: 4.1Ambient: 4.1Ambient: 4.1Control: 5.6Control: 5.6Control: 5.6Control: 4.0Control: 4.0Control: 5.3Control: 5.4Control: 5.6Ambient: 4.1Control: 4.0Control: 4.0Control: 5.6

No effect on yieldNo effect; 9°/0 greater yieldLower number of marketable roots10°/0 greater shoot growth,

16°/0 greater yieldNo effect on yield or growth9°/0 lower yield, no effect on growthNo effect on yield19°/0, 24°/0 greater yieldNo effect on yield or growthNo effect; 31 to 33% lower yieldNo effect on yield13 to 17°/0 higher root weight7 to 11 0/0 higher root weight3 to 7°/0 higher root weightNo effect; 12°/0 lower root weightNo effect on yield or growthNo effect; 25°/0 greater yieldNo effect on yield or growthNo effect on yield, lower pods/plant11 % lower seed weight, lower seeds and pods/plantNo effect on yield or growth3 to 11 % lower yield7 to 17°/0 lower yield8 to 23°/0 lower yield32°/0 greater yield, 17°/0 greater seed sizeNo effect on yield, 8°/0 smaller seed sizeNo effect on yield or growthNo effect on yield or growthNo effect on yield, 4°/0 greater weight/seedNo effect on yield, 4% greater weight/seedNo effect on yield, 17°/0 smaller seed sizeNo effect on yield, 22°/0 greater seed sizeNo effect on yield or growth

aDifferent acid rain simulants or treatment methods produced different results.bSee reference 18 to text of this section.

SOURCE: Modified from U.S. Environmental Protection Agency, “Effects on Vegetation,” The Acid Deposition Phenomenon and Its Effects, Critical Assessment ReviewPapers, Public Review Draft, 1983, except as noted above.

osition, ozone, heavy-metal deposition, drought, severewinters or a combination of these are possible causesunder investigation.

By coring trees and measuring the thickness of an-nual growth rings, scientists have observed marked re-ductions in productivity beginning about 1960 in redspruce, shortleaf pine, and pitch pine. Corings fromabout 30 other species at 70 sites throughout the Eastare currently being analyzed to determine the geograph-ic extent and severity of the problem. Routine meas-urements of tree growth by the U.S. Forest Service haveshown productivity declines in loblolly pine and shortleafpine during the 1970’s in the Piedmont region of SouthCarolina and Georgia. Again, the cause of these declinesis not yet known, but air pollution is a possible factor.

Air pollutants can influence plant health through acomplex process that depends not only on the level of pol-lution and duration of exposure but also on environmen-tal factors that influence the plant’s overall response as

a living organism under stress. As with all stress-inducing agents, air pollutants may initiate changeswithin plant metabolic systems that cause extensivephysiological modifications; sufficient change may leadto visible symptoms. In some instances, adding low pol-lutant levels to a plant’s environment may induce afertilizer-like response. This phenomenon has beenanalyzed in agronomic crops; however, no studies haveshown beneficial effects on natural ecosystems.

Continual exposure to pollutants such as ozone andsulfur dioxide can cause tree death. Other contributingor mitigating factors also may be involved (i. e., abioticor biotic disease-inducing agents or insect attack).Depending on the tree species, the seasonal stage ofgrowth, pollutant dose, and environmental conditions,many forms of injury, varying widely in impact, mayoccur. A given plant may exhibit symptoms of acute andchronic injury simultaneously. However, injury does notnecessarily imply damage (i. e., economic loss).


Figure B-9.—Percent of Land Area Capable of Commercial Timber Production

aThe U.S. Forest Service deflnes commercial timberland as lands capable of producing greater than 20 Cubic feet of industrial roundwood per acre per year, in natural stands.

SOURCE: Oak Ridge National Laboratory from U.S. Forest Service inventory data.

The potential effects of acid deposition and gaseouspollutants (e. g., ozone) on forest productivity can be dis-cussed only qualitatively at present. Figure B-10 sum-marizes the various mechanisms by which such a com-bination of pollutants might affect forest productivity.The top part of the diagram illustrates positive andnegative effects on exposed vegetation; the bottom partof the diagram illustrates positive and negative effectson vegetation through soil processes. For example, eachof the gaseous pollutants—ozone, SO2, and NOX—hasa predominantly negative effect on vegetation. Aciddeposition may have both positive and negativeeffects-fertilizing the soil with sulfur and nitrogen, butpotentially leaching nutrients from leaves and releasingtoxic aluminum from the soil.

Figure B-10 shows the net effect on the growth ofvegetation as the sum of a series of positive and negativeeffects. Site-specific factors that control plant responsesto any individual mechanism are likely to determine thenet effect on plant productivity, assuming that differentmechanisms do not interact to produce additionaleffects.

The greatest potential for negative pollutant impactson trees appears to occur in the commercial forests ofthe Southeastern Coastal Plain, the Mississippi RiverValley, the Appalachian Mountain chain, and the up-per Ohio River Valley. These regions experience bothhigh concentrations of ozone and elevated levels of aciddeposition. In each of these areas, nitrogen inputs toforests would be expected to partially offset negative im-pacts, while sulfur inputs currently exceed forest growthrequirements and probably have neither a significantpositive or negative influence at this time.

To summarize the potential for long-term forest-pro-ductivity effects from both acid deposition and gaseouspollutants, at the present time OTA can state only thatsuch interactions might occur and that their probabil-ity of occurrence is greatest in those regions of the East-ern United States outlined above. The mechanisms in-volved and the relative importance of those mechanismsto forest growth response must be studied further in or-der to better describe and eventually quantify these po-tential effects.


Implications of Potential Forest ProductivityDeclines Due to Air Pollution

If air pollution is shown to significantly affect the pro-ductivity of commercially forested timber species,potential long-term effects on forestry and related in-dustries could be of concern. OTA used in-house in-formation and analyses to identify significant factorsabout the current forest industry and how it might beaffected by potential forest productivity declines due toair pollution.

It is estimated that improved management practiceson suitable lands could double sustainable timber har-vest levels on over 90 percent of forestland in the East-ern United States. Thus, significant potential for off-setting future forest productivity declines exists.

However, if timber harvest levels do not increase, po-tential forest-productivity losses due to air pollutioncould be of particular significance for regional timbermarkets in the South. Lack of softwood reforestation onmany private nonindustrial forest lands over the pasttwo decades may decrease softwood-timber harvests inthe South, beginning about 1995. Timber supplies inthe Northeastern United States appear to be adequatefor the foreseeable future. Productivity declines, whetherof regional or local scale, could threaten the economicviability of individual lumbermills and papermills. Sig-nificant reductions in harvests over a sustained period

●

could cause mill closures; papermills are particularlyvulnerable, since they represent large capital invest-ments, and must operate very close to capacity (in gen-eral, over 90 percent) to break even.

●

Potential losses in timber production in the Northeastand South, if realized, could alter opportunities to in-crease forest-product exports, and could, at the extreme,result in increasing imports of timber from the Cana-dian Northwest.

Effects of Ozone onForest Productivity

Considerable literature is available to describe ozoneeffects on forest vegetation. Most studies examinedfoliar (leaf) injury rather than yield loss. Table B-9 liststree species that have been determined to be sensitive,of intermediate sensitivity, and tolerant of ozone. How-ever, researchers caution against overreliance on theserelative rankings, because the individual experimentsvaried in study methods used (exposure chamber, am-bient air), age of trees, and type of response measured(injury, growth).

Most of the few studies examining yield loss exposedforest tree seedlings to ozone under controlled labora-tory or greenhouse conditions. One field study, how-


Table B-9.—Relative Susceptibility of Trees to Ozone Damage

Sensitive Intermediate ResistantTree-of-Heaven Boxelder Balsam firjuneberry eastern redbud white firwhite ash Japanese larch sugar mapleswamp ash incense cedar Norway maplehoney locust sweetgum European white birchEuropean larch knobcone pine flowering dogwoodtulip poplar Iodgepole pine European beechjack pine short leaf pine American hollycoulter pine South Florida slash pine black walnutJeffrey pine sugar pine western juniperAustrian pine pitch pine swamp tupeloponderosa pine eastern white pine Norway sprucemonterey pine Scotch pine white spruceIoblolly pine Torrey pine blue spruceVirginia pine scarlet oak red pineAmerican sycamore pin oak digger pineJapanese poplar black oak Rocky Mountain Douglas firblack cottonwood common lilac common pearquaking aspen Chinese elm

●shingle oak

white oak bur oakEuropean mountain ash English oaklilac northern red oak

black locustredwoodgiant sequoianorthern white cedarAmerican basswoodIittleleaf lindeneastern hemlock

SOURCE: D. D. Davis and H. D. Gerhold, “Selection of Trees for Tolerance of Air Pollutants,” Better Trees for MetropolitanLandscapes Symposium Proceedings, U.S. Forest Service General Technical Report, NE-22:61-66, 1976.

●

ever, has measured yield reductions in mature whitepine in the Blue Ridge Mountains of Virginia.

The study compared annual radial-increment growthin tolerant, intermediate, and sensitive varieties of whitepine (Pinus strobus) (6). Observed within-species varia-tions in ozone-induced foliar injury were used to classifytrees into the three sensitivity categories. The trees werethen compared to determine how much less growth hadoccurred in the sensitive and intermediate varieties thanin their tolerant counterparts. Growth in the sensitiveand intermediate varieties was reduced by 45 percentand 15 percent for 1 year (1978), by 40 percent and 20percent over a 10-year period (1968-78), and by 28 per-cent and 15 percent over a 25-year cumulative period.These figures may be conservative, as they are basedon comparisons to ozone-tolerant tree growth in areasof known ozone occurrence (50 to 75 ppb, 7-hour aver-age, May-September yearly).

Several field studies related significant changes inforest ecosystem response to ambient oxidant concen-trations (88). The San Bernardino Mountain Study doc-umented mortality of sensitive ponderosa (Pinus pon-derosa) and Jeffrey (P. Jeffreyi) pines after bark beetlesinfested air-pollution-stressed trees (63,65). Air pollu-

tion stress appears to be shifting forest species composi-tion toward more tolerant species such as white fir.Other examples of shifts in species composition associ-ated with oxidants or mixtures of air pollutants also havebeen reported (21,60),

Fate and Effectsin Forest

Upon entering a forest

of Acid DepositionEcosystems

ecosystem, acidic pollutantssuch as sulfate and nitrate become part of a chemicalsystem regulated by a variety of natural processes, Thechemical constituents of acid deposition should beviewed as an addition to the hydrogen, sulfate, andnitrate ions produced and cycled naturally within for-est ecosystems.

This section discusses ways in which atmosphericallydeposited hydrogen, sulfate, and nitrate ions could af-fect forest nutrient cycles. The section also examines thefate and effects of deposition in excess of amounts thatcan be biologically used, or chemically trapped or neu-tralized by forest soils.

—


Effects on Forest Sulfur and Nitrogen Status

Acid deposition contains readily usable forms of theessential plant nutrients sulfur and nitrogen. Nitro-gen-deficient forests are common throughout the UnitedStates, but sulfur-deficient forests are much less com-mon, occurring primarily in the Pacific Northwest(98,99,1 14,120).

Atmospheric inputs of nitrate and ammonium couldimprove nitrogen nutrition substantially in forests of theNorth Central and Northeastern States, especially inareas near the eastern Great Lakes. In most areas ofthe West, atmospheric nitrogen inputs are much less sig-nificant when compared to the total nitrogen re-quirements of Western forests.

The sulfur deposited in some forested areas of theWestern United States may be less than that requiredfor optimal growth, but data to quantify how widely thisoccurs are scanty. Much of the Eastern United Statesappears to receive inputs equal to or in excess of treesulfur requirements. Moreover, trees require nearly 15times as much nitrogen as sulfur, on a weight basis, tosynthesize protein. The ratio of nitrogen to sulfur in at-mospheric deposition is far from this ideal valuethroughout the United States, with greater amounts ofsulfur than nitrogen deposited over most of the EasternUnited States. Thus, it would appear that substantiallygreater quantities of sulfur are being deposited than canbe used as fertilizer over the long term, and that manyforests would have to be heavily fertilized, or otherwiseenriched in nitrogen, to benefit at all from sulfur depo-sition (99).

Forests do not depend entirely on atmospheric inputsto meet nutrient requirements, as they recycle nutrients—e. g., by reclaiming them from decomposing leaves.When atmospheric nutrient inputs fail to meet growthrequirements and soil-available nutrient supplies are low(as is often the case for nitrogen), recycling processeswithin forest ecosystems and nutrient translocation fromone part of a tree to another help supply nutrients to

growing tissues. Thus, while increased atmospheric ni-trogen and sulfur inputs might benefit forests limitedin those nutrients, under undisturbed conditions at-mospheric inputs do not have to equal plant uptake to

maintain site fertility. However, to maintain site fertil-ity in harvested forests, inputs must compensate for theamount of nutrients removed by logging.

Effects on Forest Cation Nutrient Status

In addition to supplying some nutrients, acid depo-sition (and naturally produced acids) can remove othernutrients stored in leaves, the litter layer on the forestfloor, or the soil. The hydrogen ions (i. e., the “acid-ity’ of acid deposition can replace or ‘‘leach’ nutri-

ent cations, * removing these essential nutrients fromthe forest ecosystem.

Acid deposition can remove essential nutrient cations(e. g., calcium) directly from tree foliage. If the rate ofnutrient loss is greater than can be replaced through theroots, nutrient deficiency will result. Scientists do notknow which tree species are most susceptible to foliarnutrient loss, or the level of acid deposition at whichsuch loss becomes harmful. For any given species, therate of loss probably depends on both the total amountand concentration of acid-producing substances (sulfateand nitrate) deposited on leaf surfaces.

Nutrient leaching from soils is somewhat different.No cation leaching will occur unless the acid-producingsubstances can travel freely through the ecosystem (47).Since forest nitrogen deficiencies are very common andnitrate is taken up readily by forest vegetation (1 ,74),atmospheric nitrate inputs are unlikely to be mobileenough to leach significant amounts of nutrient cationsfrom most forest soils. Sulfate, the other major acid-pro-ducing substance in rainfall, can travel through manytypes of forest soils and is, therefore, of greater concern.

While acid deposition can accelerate cation leachingrates, the magnitudes of these increases must be com-pared to losses from natural leaching processes. The rel-ative importance of deposition-induced leaching dependson: 1 ) the amount of acid input at a given site, 2) therate of soil leaching by natural processes (8, 10,66), and3) the ability of soils to buffer against leaching (e. g.,by “adsorbing” or trapping sulfate onto their surfaces)(46). Furthermore, a number of variables govern howaccelerated leaching ultimately affects forest cation nu-trient status, most notably: 1) the amount of exchange-able cations, 2) the rate at which nutrients are replacedthrough mineral weathering (74,9 1), 3) forest cation nu-trient requirements, and 4) management practices suchas harvesting (44).

If the quantities of soil cation reserves within a forestecosystem are large relative to leaching rates (e. g., incalcareous soils), a doubling or tripling of leaching ratesdue to acid rain probably would be of little consequence.If reserves are small (e. g., in highly weathered soils),doubling or tripling of leaching rates may have long-term significance. Soils in which current input levels ofacid deposition can significantly deplete nutrient re-serves over less than many decades are probably rare,however. Nonetheless, given a sufficiently large inputfor a sufficient amount of time, acid rain must even-tually deplete these reserves.

Currently, few forests of the United States have ca-tion deficiencies, although notable exceptions are knownin certain forests of the Northeast (90). An intensive

“Nutrients [hat have the same chemical charge as hydrogen Ions, e g.,calcium, magnesium, and potassium


study of a central Adirondack Mountain forest indicatesthat atmospheric sulfate deposition has increased ratesof soil nutrient-cation leaching substantially (66). Sincethese soils are quite low in available cation reserves, theresearchers concluded that, “Chronic leaching by [sul-furic acid] combined with internally generated organicacids may represent a real threat to the nutrient statusof many Adirondack forest soils’ (66). However, theauthors acknowledge that total soil cation reserves andweathering rates (or rates at which these reserves becomeavailable to trees) are unknown, and that a completeassessment must encompass these factors. Acid rain itselfmay cause soil weathering rates to increase, potentiallyoffsetting accelerated nutrient leaching to some extent.

Effects of Aluminum Mobilization

Soil scientists have long known that soils release alu-minum under sufficiently acid conditions (5, 121 ). Alu-minum is also known to be toxic to plant roots in suffi-cient concentrations, either killing them directly orinterfering with nutrient uptake (especially phosphorusand calcium) (71, 73). Researchers recently found amarked increase in soil aluminum concentrations overa 13-year period in a beech and Norway spruce forestsoil at the Soiling site in West Germany (58, 101). Theyattributed the change to a combination of natural acidi-fying processes within the forest ecosystem and atmos-pheric acid inputs. Furthermore, the authors believe thataluminum levels have become toxic to tree roots, pos-ing a situation with ‘‘serious consequences for forestryin Central Europe.

The findings of these West German researchers arecause for concern, but they may not apply to all foresttypes. Acid and sulfate inputs are very high at the Soll-ing site, as would be necessary to further acidify a soilthat was initially very acid. Moreover, species varywidely in their susceptibility to aluminum toxicity. *

Similar declines have been observed in red spruce inthe Northeastern United States. However, recent workfails to support the soil aluminum hypothesis in thesecases. Specifically, researchers found no changes in soilpH over a 15-year period (1965-80) and no relationshipbetween tree vigor and root or foliar aluminum concen-tration. The causes for the decline in red spruce are un-known as of this writing. Acid rain, aluminum concen-trations, and forest decline, but acid rain (perhaps viaother mechanisms) remains one of several working hy-potheses under investigation.

“Researchers repon great variations m toxicity thresholds among several treespecies, ranging from 10 mg/1 Al in solution for a poplar hybrid to 80 to 120mg/1 in oak, birch, and pine (61 ). Others report Al concentrations in‘‘equ ilibrium soil solution (i. e., solution obtained after extraction of soil withwater for 24 hr) of less than 3 mg/1 (101 ) More recently, Al concentrationsof nearly 20 mg/1 in soil solutions were reported from the spruce stand at Soil-ing (58).

It must be emphasized that acid rain effects are site-specific, depending on the amount of acid input and onthe vegetation, soils, and nutrient status of the sitereceiving such inputs. Forest ecosystems in general can-not be expected to respond to acid rain in any singleway.

The Regional Distribution of Soilsat Risk From Acid Deposition

Analysts have proposed and used several sets of sen-sitivity criteria to define geographical regions most sus-ceptible to acid deposition effects. Each set is based onscientific concepts that aim at particular target orga-nisms or ecosystems (e. g., forests or aquatic ecosystems).Those directed toward aquatic effects emphasize bed-rock geology (3 1,67), while those directed toward soilseffects emphasize cation exchange capacity (C EC) andbase saturation (52,59).

Scientists at Oak Ridge National Laboratory haveclassified unmanaged (i. e., forest or range) soils accord-ing to their sensitivity to three types of acid-deposi-tion-induced changes: 1) losses of essential nutrientssuch as calcium and magnesium, 2) release of toxicmetals such as aluminum, and 3) further acidification.

The classification scheme uses three soil properties:1) whether the soil adsorbs (chemically traps) sulfate;2) the soil’s cation exchange capacity (CEC); ** and 3)the PH (acidity) of the soil, which also indicates basesaturation, i.e., the relative proportion of basic cations(nutrients such as calcium and magnesium) to acidic ca-tions (hydrogen and aluminum).

Table B-10 outlines the relative sensitivities of vari-ous soil types; figures B-11 and B-12 describe the chem-ical exchanges that acid deposition produces in each ofthese soils. Figure B-13 maps the extent and locationof these soils in the Eastern United States. The threetypes of potential soil changes attributable to acid depo-sition are discussed separately below.

RELEASE OF ALUMINUM

As shown in table B-10, soils that are naturally acidic(i.e., pH below about 5) and that do not adsorb sulfate,are considered most likely to release toxic metals suchas aluminum. Figure B-11 illustrates the mechanismschematically. Sulfate and hydrogen ions from aciddeposition reach the soil layer. Because the soil does nottrap sulfate, the sulfate is free to move through the soil.The associated hydrogen ion can either: 1) travel withthe sulfate, or 2) be exchanged on the soil surface fora base cation (e. g., calcium or magnesium) or an acid

“ “The total amount of cations (positively charged ions such as calclum,magnesium, atuminum, and hydrogen) the soil can hold.


Table B-10.—Theoretical Sensitivities of Forest Soils to Acid Deposition

Soil properties Terrestrial sensitivity to:

SoilBase acidification

pH CECa cation loss (surface soils)

I. Non-sulfate-absorbing soils1. >6 High High Low2 . > 6 Low High Low-moderate3. 5-6 High High Moderate4. 5-6 Low High High5 . < 5 High Moderate Moderate6 . < 5 Low Moderate Moderate

IL Sulfate-absorbing soils7. >6 High Moderate Low8 . > 6 Low Moderate Low-moderate9. 5-6 High Low Moderate

10. 5-6 Low Low High11. <5 High Low Moderate12. <5 Low Low Moderate

Alsolubilization

LowLow-moderate

ModerateModerate

HighHigh

LowLowLowLowLowLow

%Cation Exchange Capacity (CEC).bHigh CEC = above 9.0 meq/ml, low CEC = below 9.0 meq/ml

SOURCE: Oak Ridge National Laboratory, 1983.

cation (aluminum or another hydrogen ion). Becausealuminum both dissolves most easily and is most plen-tiful in acid soils (fig. B-11c), these soils release the great-est amounts of aluminum.

Figure B-12 illustrates soil processes in sulfate-adsorb-ing soils. Because these soils can trap both sulfate andthe associated hydrogen ion from acid deposition, lessaluminum is released.

Figure B-13 shows the distribution of soils consideredsusceptible to aluminum release, based on county-levelsoil data. The medium-grey areas are the naturally acid,nonsulfate adsorbing soils discussed above. These coverNew England, and parts of northern New York State,the upper Midwest, and the South. Acid soils that canadsorb sulfate are shaded as light grey. These cover largeareas of the South and South Central States. Becausesoils classified as adsorbing sulfate often do so only indeeper soil layers, the surface layers in these regions stillmight be susceptible to aluminum release.

SOIL ACIDIFICATION

Soils thought to be sensitive to further acidificationare moderately acid (pH about 5 to 6) with low CEC.Such soils occur to a very minor extent in those regionsreceiving significant inputs of acid deposition. As shownas the darkest areas on figure B- 13, these soils predom-inate in scattered counties east of the Mississippi (i. e.,counties in Illinois, Indiana, Georgia, and Tennessee).Other areas of the East receiving higher deposition levels(e.g., parts of the Adirondacks) probably have some soilsof this type, but not in sufficient quantities to constitutea county’s predominant soil type.

For these moderately acidic soils, concerns over fur-ther acidification include: 1 ) potential effects on soilbiota, 2) release of aluminum if acidity increases tobelow a pH of about 5, and 3) the loss of nutrients fromthese soils, as discussed below.

NUTRIENT DEPLETION

As shown in table B-7, those soils most susceptibleto nutrient cation (calcium, magnesium, and potassium)loss are soils with a moderate to high pH that do notadsorb sulfate. Again, figures B-11 and B-12 show themechanisms of nutrient loss. As sulfate and associatedhydrogen ions enters the soil layer, the hydrogen ionscan be exchanged for base cations. Sulfate-adsorbingsoils trap hydrogen ions (fig. B-12), while lower pH soils(e. g., fig. B-11c) exchange most of the hydrogen ionsfor aluminum and remove fewer nutrient cations.

Of the soils listed as most susceptible to nutrient lossin table B-9, only the moderate pH, nonsulfate adsorb-ing soils with low CECs have both a high potential fornutrient loss and low enough nutrient levels so that thisloss might be significant. These are the same soils dis-cussed above as being susceptible to further acidifica-tion, and are shown on figure B-13 as the darkestregions.

Though listed as only moderately susceptible to nu-trient loss in table B- 10, naturally acid, nonsulfate-adsorbing soils typically have the lowest quantities ofstored nutrient cations. Some of these areas may havesuch low nutrient levels that further loss might affectforest productivity. Such areas might be located withinthe medium-grey regions shown in figure B-13; how-

99 - 413 0 - 84 - 1 fj s QL . 3


Figure B-n .—Schematic Diagrams of Soil Leaching in Non-Sulfate-Adsorbing Soils

(c) Cation-exchangecapacity

Input

Soilinteractions

output

Soilinteractions

output

Input

Soilinteractions

output


Figure B-12. -Schematic Diagrams of Soil Leaching in Sulfate-Adsorbing Soils

(b)

(c)

Cat ion-exchangecapacity

/Fe, Al oxides

100

‘/0 B a s esaturation

Input

Soilinteractions

output

Input

Soilinteractions

output


Figure B-13.-Soil Sensitivity to Acid Deposition (nonagricultural)

Forested and range areas with soils thought to be susceptible to the effects of acid deposition. Shaded areas represent countiesin which a susceptible soil type predominates. The three levels of shading correspond to different soil types, and potentialeffects, rather than to degrees of susceptibility.

Soils most susceptible to furtheracidification and nutrient loss

Naturally acidic soils mostsusceptible to aluminum release;nutrient loss might be significant

Naturally acidic soils potentiallysusceptible to aluminum release;surface soils might allow aluminumrelease, but subsurface soils mightnot be susceptible


ever, whether nutrient loss rates exceed natural replace-ment rates from weathering is unknown.

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York, 1980).Reagan, J. A., EPA, personal communication to OTA,1983.Reinert, R. A., Shriner, D. S., and Rawlings, J. O.,“Responses of Radish to All Combinations of ThreeConcentrations of Nitrogen Dioxide, Sulfur Dioxide, andOzone, ” J. Environ. Qua]. 11:52-57, 1982.Research Management Committee (RMC), The Nation-al Crop Loss Assessment Network (NCLAN): 1980 An-nual Summer Report (Corvallis, Oreg. : Corvallis Envi-ronmental Research Laboratory, EPA, 1981).Roman, J. R., and Raynal, D. J., “Effects of Acid Pre-cipitation on Vegetation, Effects of Acid Precipitationon a Forest Ecosystem, D. J. Raynal, A. L. Leaf, P. D.Marion, and C. J. K. Wang (eds. ) (Syracuse, N. Y.: StateUniversity of New York, 1980).Rosenquist, 1. Th., SurJord/Surt Vann (Oslo, Norway:Ingeniorforlaget, 1977).Salathe, L., and Maxwell, D., USDA, personal com-munication to OTA, 1982.Santamour, F. S., Jr., ‘‘Air Pollution Studies on Platanusand American Elm Seedlings, Plant Dis. Rep. 53:482-484, 1969.Seip, H. M., ‘ ‘Acidification of Freshwater—Sources andMechanisms, Ecological Impact of Acid Precipitation,D. DrabI/s and A. Tollan (eds. ) (Mysen, Norway: Johs.Grefslie Trykkeri A/S, 1980).Shriner, D. S., ‘ ‘Effects of Simulated Acidic Rain onHost-parasite Interactions in Plant Diseases, ’ Phytopath -olo~y 68:2 13-218, 1978.Shriner, D. S., “Terrestrial Vegetation-Air Pollutant In-teractions: Non-gaseous Pollutants, Wet Deposition,Air Pollutants and their Effects on Terrestrial Ecosys-tems, A. H. Legge and F. V. Krups (eds. ), in press (,NewYork: John Wiley, 1983).Shriner, D. S., ‘ ‘Interactions Between Acidic Precipita-tion and S02 or Os: Effects on Plant Response, Phyto-parhology News (Abstract) 12: 152, 1978.Shriner, D. S., and Johnston, J. W., ‘‘Effects ofSimulated, Acidified Rain on Modulation of LeguminousPlants by Rhizobium Spp., “ Environ. Exp. Bet. 21 :199-209, 1981.Smith, W. H., Air Pollution and Forests: InteractionsBetween Air Contaminants and Forest Ecos~stezrm (.New

York: Springer-Verlag, 1980).Smith, W. H., “Air Pollution: A 20th Century AllogenicInfluence on Forest Ecosystems, Effects ofAir Pollutants

238 “ Acid Rain and Transported Air Pollutants: Implications for Public Policy

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App. B- Effects of Transported Pollutants ● 2 3 9

B.3 MATERIALS AT RISK

Air pollutants are one of a number of environmentalfactors—including humidity, temperature fluctuations,sunlight, salts, and micro-organisms—known to causematerials damage. Studies have demonstrated that abroad range of materials, including building stone, rub-ber, zinc, steel, paint, leather, textiles, paper, andphotographic materials are affected by such pollutantsas sulfur oxides (SOX), nitrogen oxides (NOX), andozone. For most of the materials under discussion, S0x

(i,e., sulfur dioxide and its transformation products, in-cluding sulfates and sulfuric acid) are the chief anthro-pogenic cause of damage; however, rubber is affectedchiefly by ozone, while ozone and NOX have the great-est effect on textile dyes. Table B-11 summarizes thetypes of damage that occur to various categories of ma-terials, as well as natural causes of deterioration, meth-ods of measurement, and available mitigation measures.

Pollutants generally damage materials in ways thatare not qualitatively different from the weathering ef-fects caused by the natural environment. Consequently,estimating how much of observed damage is contrib-uted by pollution sources is extremely difficult. The di-verse pollutant mix characteristic of heavily industrial-ized urban areas-where greatest amounts of materialsdamage would be expected—increases the difficulty ofpinpointing the cause and mechanisms of damage. Inaddition, environmental legislation and changes in man-ufacturing processes have caused pollution patterns tochange over time; in particular, concentrations of largeparticulate have decreased dramatically over the lastdecade. As a result, pollutant-atmospheric conditionsthat may have contributed significantly to such notableeffects as the deterioration of sculptural stone may nolonger prevail in the United States. Finally, the rela-tive contribution of local v. transported pollutants toobserved materials damage is unknown. However, sinceboth pollution sources and quantities of sensitive mate-rials tend to be concentrated in urban areas, most re-searchers consider that local-scale pollutants account forthe bulk of currently recognized materials damage.

Two kinds of materials damage are of concern: 1)damage to culturally significant structures and monu-ments, and 2) damage to reparable or replaceable ‘ ‘com-mon construction material items. The effects of airpollutants on unique or historically important statuary,monuments, buildings, or other artifacts are often ir-reparable; consequently, their cost to society cannot bedescribed completely in monetary terms. Damages tosculptural stone and bronze, and to historic buildingsconstructed of such sensitive materials as marble, sand-stone, and limestone, are frequently of this nature.

Pollution-induced damages to replaceable materials,and their economic costs, are potentially quantifiable.However, a great deal of information must be taken intoaccount in estimating pollution-related losses. Sincethose damages tend to be similar in form to other envi-ronmental damages to materials, they are likely to af-fect the rate at which preventive, mitigative, or replace-ment activities occur, but not to be their sole cause.Little information is available on how pollutant-relateddamages affect normal maintenance and repair activi-ties. Analysts also need information on the amount ofmaterials damage for which specified pollutant levels areresponsible. Most of our knowledge about the rates atwhich specified pollutant levels cause individual mate-rials to deteriorate is based on field and laboratory ex-periments using small samples of materials rather thanmeasurements from actual structures. Knowledge aboutpollutant-material interaction is further limited by thefailure of many studies to consider (and measure) impor-tant environmental factors. Moreover, estimates of thetotal quantities of materials exposed and their distribu-tion are limited, so that little information is availableto evaluate the extent or the economic consequencesof such damage over large geographic areas. Informa-tion gaps in each of these areas have, to date, preventedinvestigators from developing reliable estimates of theoverall economic effects of materials damage.

Other factors that may affect how much damage takesplace, and about which little is currently known, are:1) microclimatic variations, 2) the physical placementof materials, and 3) chemical and physical variationsin seemingly similar materials. For example, rain maywash sulfate and nitrate particles from exposed surfacesand remove the build-up of soluble pollutant-materialresidues, while the particles that remain on rain-shel-tered surfaces may cause greater damage. Variationsin the properties of stone might cause samples from eventhe same quarry to deteriorate at significantly differentrates under similar atmospheric exposure conditions.

Several laboratory and field experiments have esti-mated ‘ ‘dose-response’ relationships for a limited num-ber of specific pollutant-material interactions. Greatestamounts of data are available on the effects of S0x onsuch metals as zinc and steels under different weather/at-mospheric conditions. Sulfur oxides corrode metals; thevolubility of a given metal, and its ability to form stable,protective metal oxide coatings when exposed to the at-mosphere, determine its ability to withstand corrosion.Metal corrosion always requires moisture, and tends toaccelerate above critical humidity levels that range from60 to 80 percent, depending on the particular metal.

Table B-Il.—Air Pollution Damage to Materials

Principal airMaterials Type of impact Pollutants Other environmental factors Mitigation measures

Metals

Building stone

Ceramics andglass

Paints andorganic coatings

Paper

Photographicmaterials

Textiles

Textile dyes

Leather

Rubber

Corrosion, tarnishing Sulfur oxides andother acid gases

Surface erosion,soiling, black crustformation

Surface erosion,surface crustformation

Surface erosion,discoloration,soiling

Embrittlement,discoloration

Microblemishes

Reduced tensilestrength, soiling

Fading, color change

Weakening,powdered surface

Cracking

Sulfur oxides andother acid gases

Acid gases,especially fluoride-containing

Sulfur oxides,hydrogen sulfide

Sulfur oxides

Sulfur oxides

Sulfur and nitrogenoxides

Nitrogen oxides,ozone

Sulfur oxides

Ozone

Moisture, air, salt, particulatematter

Mechanical erosion,particulate matter, moisture,temperature fluctuations,salt, vibration, CO2, micro-organisms

Moisture

Moisture, sunlight, ozone,particulate matter,mechanical erosion, micro-organisms

Moisture, physical wear,acidic materials introducedin manufacture

Particulate matter, moisture

Particulate matter, moisture,light, physical wear, washing

Light, temperature

Physical wear, residual acidsintroduced in manufacture

Sunlight, physical wear

Surface plating or coating, replacement withcorrosion-resistant material, removal tocontrolled environment

Cleaning, impregnation with resins, removalto controlled environment

Protective coatings, replacement with moreresistant material, removal to controlledatmosphere

Repainting, replacement with more resistantmaterial

Synthetic coatings, storing controlledatmosphere deacidification, encapsulation,impregnation with organic polymers

Removal to controlled atmosphere

Replacement, use of substitute materials,impregnation with polymers

Replacements, use of substitute materials,removal to controlled environment

Removal to a controlled atmosphere,consolidated with polymers, or replacement

Add antioxidants to formulation, replace withmore resistant materials

SOURCE: U.S. Environmental Protection Agency, “The Acidic Deposition Phenomenon and Its Effects,” Critical Assessment Review Papers, vol. II, EPA-600/8-83-016B, May 1983.

App. B—Effects of Transported Pollutants ● 2 4 1

However, results from certain recent studies suggest thatthe rate of pollutant-induced corrosion depends most on‘‘time-of-wetness’1—i.e., the relative length of time ametal surface is wet (e. g., from morning dew).

Studies have shown that current ambient concentra-tions of sulfur dioxide (S02) can accelerate the corro-sion of exposed ferrous metals, and that higher relativehumidities significantly increase the extent of SO2-induced corrosion. However, most uses of ferrous metalproducts involve the application of such protectivecoatings as paint and zinc, or the addition of protectivealloys. Zinc coatings, used primarily for galvanizingsteel, are also corroded by atmospheric S02 concentra-tions, potentially allowing steel underneath to rust, andaccelerating maintenance or replacement.

‘J E }’ocum a n d N S Baer, “ E f f e c t s on Matermls,” T-he AcJd~c Deposi-[mn Phenomenon and [M Eflecrs, Cr~tlcaf Assessment Review Papers, publicreview draft, U. S Envlronmenta] Protectmn ,Agency, 1983

The extent of zinc corrosion at given ambient S02

levels depends on such climatic factors as relative hu-midity, windspeed, and time-of-wetness; and on the sur-face geometry of the product. The economic importanceof zinc has caused its reaction to sulfur pollutants to beextensively studied. A number of researchers have de-veloped dose-response estimates for zinc coatings. Forexample, figure B-1 4 shows an experimental estimateof the difference between rates of zinc corrosion for largesheets of roofing and siding and those for wire fencing,under different environmental conditions. Rates for gal-vanized wire and fencing are approximately doublethose of galvanized sheet exposed to the same environ-ment. The figure suggests that differences between rel-ative humidities in various areas of the country are moresignificant to corrosion rates than differing S02 levels.One researcher has calculated that, for an area with anaverage humidity of 70 percent, rust could first appearon fencing after 10 years at S02 concentrations of 80

Figure B-14.– Estimated Corrosion Rates for Zinc Coatingson Galvanized Steel

— Galvanized roofing and siding

SOURCE: Derived from equations in: “Review of the National Ambient Air Quality Standards for SulfurOxides: Assessment of Scientific and Technical Information, ” US. Environmental ProtectionAgency, 1982.


µg/m (the primary ambient air quality standard), as op-posed to an interval of about 30 years required for rustto appear in the absence of S02. First rust would occurlater on most products, depending on the surface geom-etries and/or coating thicknesses involved.2

A variety of paints has been found to be susceptibleto SO2-induced damage. However, the available evi-dence suggests that climate tends to play a far more sig-nificant part in determining deterioration rates thanSO2 concentrations. Sulfur oxides appear to acceleratenormal erosion processes in paint, and to interfere withdrying processes of certain paints. Experiments havefound that oil-based paints are the most susceptible todamage, probably because they use extenders that re-act readily with acidic pollutants. No recent studies ofthe effects of pollutants on paints are available; a limitednumber of earlier studies were performed during theearly 1970’s under atmospheric/pollutant conditions thatmay differ substantially from current ones.

Extensive qualitative information is available on theeffects of SO2 on stone and masonry. In general, thegreater the porosity or permeability of stone and ma-sonry, the greater its vulnerability. Such carbonatestones as limestone and marble are particularly sensitiveto damage from acidic pollutants. Water serves as a me-dium for bringing acidifying pollutants into contact withthese materials. Crumbling of stone through “normal’deterioration (i. e., through freezing and thawing) mayfurther expose stone surfaces to sulfur pollutants. Sulfuroxides react with calcite, the major constituent of car-bonate stone and a cementing material in some sand-stones, to form calcium sulfate. Calcium sulfate depositscan form crusts and/or be dissolved by runoff waters,washing away or eroding a layer of stone in the proc-ess. Alternatively, calcium sulfate can be transportedinto the body of the stone or masonry, where it maycrystallize and cause the material to crumble orfragment.

In addition, bacteria on the surface of buildings con-vert atmospheric S02 into sulfuric acid for use as a di-gestive fluid. This fluid can react with the calcium car-bonate in limestone, marble, or sandstone to producecalcium sulfate, eroding the building surface when itflakes off or dissolves. The various processes have thesame net effect: accelerated stone weathering that causesstatues to lose detail and reduces the structural integrityof stone buildings.

A recent study of marble deterioration in the UnitedStates has measured decay rates on the order of 2.0 mm/100 years; however, studies of more reactive stones inEuropean cities have yielded substantially greater de-

‘U S Environmental Protectmr Agency, Review of the National AmbientAir Qualltj’ Standards fbr Sulfur ox]des Assessment of.% ientific and Techni-cal lnfbrmarmn, OAQPS Staff Paper, EPA-4501 5-82-007, 1982

terioration rates. Ongoing investigations of 3,900 mar-ble tombstones located in 21 U.S. National Cemeteriesare developing data on marble decay in headstones ex-posed to the environment for 1 to 100 years. Since themarble for these tombstones is supplied from only a fewquarries, the effects of climatic and pollutant conditionson a relatively standardized stone can be examinedacross several regions. Preliminary results show the sizeof grain in the marble, total amount of precipitation,and local air quality to be significant factors affectingdecay.

Efforts to estimate aggregate materials damage to theEastern United States, whether in physical or economicterms, are hampered by the lack of available informa-tion on the distribution of sensitive materials through-out the regions subject to elevated pollution levels.Materials at risk may not be distributed simply as afunction of population density; limited field surveys sug-gest that the period of settlement and urban develop-ment, and the local availability of particular materials,also may be influential, For example, a recent fieldsurvey of the quantities of paint, galvanized steel, andstructural concrete exposed to different concentrationsof S02 inthe greater Boston area suggests that substan-tially smaller quantities of galvanized steel may be ex-posed to atmospheric conditions than generally has beenassumed. 3 OTA attempts to develop regional materialsinventories and/or reliable surrogates for estimation pur-poses were unsuccessful.

An estimate of U.S. historic resources exposed to ele-vated ambient concentrations of S02 has been preparedunder the United States-Canada Memorandum of In -tent on Transboundary Air Pollution. 4 Using data fromthe National Register of Historic Places, which includessites either associated with an event or person, havingarchitectural or engineering significance, or potentiallycontributing to historic studies, researchers estimatedthat approximately 16,800 of the 18,300 sites registeredas historic places in the 31 Eastern States are in coun-ties that experience average ambient S02 concentrationsless than 60 µg/m3. About 900 sites experience S02 con-centrations ranging from 60 to 80 µg/m3, and about 600sites are in counties experiencing concentrations above80 µg/m3. Historic places in eight States—Maine, NewHampshire, New York, Pennsylvania, West Virginia,Illinois, Indiana, and Ohio—are exposed to the highestlevels of S02 concentrations. However, only in twoStates—New York and Illinois—are more than 20 per-cent of the registered historic places exposed to annualaverage S02 concentrations above 80 µg/m3. While such

1’I’RC Environmental Consultants, Air Pollurion Damage CO Msrs-Made Ma-terials. Ph,vsmal and Economic Esr~mates (Pato Alto, Calif.: Electric Power Re-search Institute, EPRI EA-2837, 1983).

‘“ Impact Assessment, ” Work Group 1, U.S. -Canadian Memorandum ofIntent on Transboundary Air Pollution, January 1983.


a survey can be helpful in indicating an area’s relativeexposure to potential damages, the ambient S02 levelschosen to categorize levels of exposure are arbitrary, rep-resenting convenient indicators rather than some knownthreshold below which materials damage would not takeplace.

Predicting human responses is perhaps the most sig-nificant difficulty in estimating the consequences ofpollution-induced materials damage. Individuals con-fronted with obvious deterioration may choose to ignoreit, accelerate cleaning, painting, or replacement, or sub-stitute a less susceptible material. Unless the damagecauses some change in the material’s utilization or re-sults in some cost to owners, it will have no measurableeconomic significance. For example, metal guardrailson highways are likely to suffer damage from air pol-lutants; however, highway accidents generally restricta guardrails useful life to a greater extent than does airpollution. Ozone causes rubber and other elastomers tolose elasticity prematurely, and become brittle. Conse-quently, automobile tires and other exposed productsare routinely manufactured with antioxidant agents—the cost of these additives, rather than a shortening ofusable life, represents this economic effect of air pol-lution.

Since the early 1970’s, a number of studies have cal-culated annual costs of materials damage due to air pol-lutants by estimating amounts of damage and derivingsome monetary equivalent for these damages. While theavailability of dose-response relationships for certainpollutant-material interactions permit this type of anal-ysis, the uncertainties involved are quite large. More-over, such studies still must rely on broad hypothesesabout material exposure and individual economicbehavior.

For example, a recent study estimated the amountby which materials damage would be reduced if Euro-pean OECD member countries decreased S0x emis-sions by about 20 percent and 50 percent from projectedemissions of about 24 million tons in 1985.5 Estimateswere made only for corrosion to zinc and galvanizedsteel, and for damage to paint coatings. The study as-sumed that each of these materials was used in propor-tion to the population, using OECD annual statisticson the use of paint and of zinc for galvanizing in mem-ber countries. Galvanized materials were assumed tobe unpainted initially; sheet and products manufacturedfrom sheet were assumed to be painted, and wirereplaced, after some corrosion occurred. Repainting was

j{)rqanizat ion for Economl[ Cooperation and Development (OECD), 7’he(.’[tsts and Benefits of.~u]phur OXKIC Corr[ml A ,we(hod[~lqq”cal StU~~J’ [ParisOECD, 1981).

assumed to occur at the economically optimal time; how-ever, materials older than 25 years were excluded, andno consideration was given to withdrawal of materialsprior to that time. These assumptions yielded an esti-mate that costs of damage would be reduced by $450million annually (1979 dollars) if emissions were reducedby about 20 percent, and by $960 million annually ifemissions were reduced by about 50 percent, by 1985.

A recent study commissioned by EPA’s Office of AirQuality Planning and Standards used macroeconomicand statistical techniques—rather than physical dose-response approaches—to estimate pollution-related eco-nomic losses from materials damage.6 The method sta-tistically estimates how much of the observed variationsin expenditures for goods and services sensitive to dif-fering air pollution levels is due to a variety of economicand climatological factors, and how much of the remain-ing variation can be attributed to differing S02 levels.This methodology has the advantage of taking into ac-count a wider variety of potential responses to pollu-tion-related damages (e. g., relocating, substituting pol-lution-resistant materials, doing nothing) than studiesassuming that all perceived damages would be remediedby repair or replacement. The study has the furtheradvantage of taking into account costs due to air pollu-tion, but not perceived as such—e.g., accelerated de-preciation of machinery. However, such statistical meth-ods can show only that a correlation exists betweenpollution and the materials-related costs, and cannotprove that pollution causes the economic effect.

The EPA-sponsored study calculated the value of re-ducing SO2 levels nationwide from the primary NAAQS(365 µg/m3, 24-hour averaging time) to a hypotheticalsecondary standard of 260 µg/m3 (24-hour averagingtime). * Calculations of benefits were made for house-holds in 24 standard metropolitan statistical areas forelectric utility maintenance; for agriculture; and for sixselected industries for which adequate economic datawere available— 1 ) meat products, 2) dairy products,3) paperboard containers and boxes, 4) fabricated struc-tural metal products, 5) metal forging and stampings,and 6) metalworking machinery. * * Results were then

b~. H. Manuel, Jr. , et al. , ‘ c Benefits Analysls of Alternate Secondary Na-tional Ambient Air Quafity Standards for Sulfur Iloxide and Total SuspendedPart iculate , produced by Mathtech, Inc., under contract to U.S Envu-on-mental Protection Agency, OAQPS, Research Triangle Park, N .C., 1982

*The current secondary standard—1 ,300 pg/mJ, 3-hour averaging time—was found to be less restrictive, for most Ioeations, than the primary standard.Using statistical averaging techniques to match 3-hour to 24-hour standards,only 5 counties in the country (out of 182 counties for which air quality datawere available) would require additional controls to meet the secondary stand-

ard, as compared to the primary standard.● *These mdustrir=s correspond to Standard Industrial Classdication (SIC)

codes 201, 202, 265, 344, 346, and 354.


extrapolated to households throughout the United in the United States. These results cannot be extrapo-States, comparable manufacturing sectors, and electric lated to provide estimates of benefits to the Nation over-utility operation and maintenance. The study concluded all; the lack of necessary data precludes analyzing thethat reducing S02 emissions in urban areas to meet the remainder of the Nation’s economy in this manner.260 µg/m3 standard would create benefits of approx-imately $300 million annually for about half of thehouseholds and 7 to 9 percent of the producing sector*

“The study defines the ‘ ‘producing sector’ to include agriculture, t’orestrv,and fisheries; mining and construct ion, manufacturing; transportation, com-munication, and util itles, commercial and services, government; and other

B.4 VISIBILITY IMPAIRMENT*

Introduction

An observer’s perception of “visibility” integratesseveral factors—general atmospheric clarity or haziness,the total distance over which objects can be seen, theirapparent color and contrast with the sky, and discerneddetails of line, texture, and form. Visibility degradationis one of the most obvious effects of air pollution. Thepresent Clean Air Act (CAA) addresses the impairmentof visual range in pristine areas, atmospheric discolor-ation, and the presence of actual smoke plumes (’‘plumeblight’ ‘). The reduction in visibility from many and di-verse sources spreading over a large area-regional haze—has not yet been addressed. Regional haze reducesvisibility in all directions from an observer, is relativelyhomogeneous, and can occur on a geographic scaleranging from a city to a multi-State region. Haze con-ditions can reduce contrast, cause distant objects todisappear, and nearby objects to appear discolored and‘ ‘flattened, add brown or grey discoloration to the at-mosphere, and decrease the number of stars visible inthe night sky.

Visibility impairment is of concern both for estheticreasons (especially in areas of great natural beauty) andpractical concerns (transportation operations). Limitedstudies suggest that actual measurements of visibilitycorrelate with: 1) perceived air quality, and 2) perceivedproperty values in Los Angeles and the rural Southwest.Preliminary attempts to quantify visitors’ “willing-ness-to-pay’ to preserve scenic vistas have been quitevariable. The major effects of visibility on transporta-tion are related to air traffic. Available data show thatepisodic regional haze over large segments of the Easttends to curtail some segments of general aviation air-

craft and slow commercial, military, and other instru-ment flight operations on the order of 2 to 12 percentof the time during the summer. The Federal AviationAdministration (FAA) restricts visual flight operationswhen visibility falls below 3 miles. Table B-12 sum-marizes efforts to characterize the social, economic, andpsychological value of various levels of visibility.

A variety of natural and anthropogenically producedparticles are capable of interfering with the passage oflight and contributing to regional haze. Liquid or solid par-ticles* * ranging from 0.005 micrometer (pm) to coarsedusts on the order of 100 µm can either scatter or ab-sorb light, reducing visibility through the extinction oflight. Theoretical and empirical results provide strongevidence that visibility reduction caused by urban andregional haze normally is controlled by fine particles,primarily sulfates (smaller than 2.5 µm in diameter).The only important situations in which large particlesdominate are such naturally occurring phenomena asprecipitation, fog, and dust storms, or manmade phe-nomena like construction, agricultural and forest slash-burning, and open-pit mining.

Factors Affecting Visibility

Natural

Natural causes of impaired visibility include dust, fog,low clouds, precipitation, elevated humidity, seaspray,volcanic emissions, and forest fires. Humidity is a par-ticularly significant visibility determinant, as it not onlyreduces visibility levels in itself, but also affects the vis-ibility-reducing properties of other airborne materials.At high humidity levels, fine airborne particles take up

● This appendix is based primardy on the OTA background paper “Review “ ● Nitrogen dioxide is the only gaseous pollutant in the atmosphere capableof the I_ong-Range Transport of Sulfate Contribution to Vlsibilitv Impairment, of contributing to the extinction of light; however, its concentrations are rarelyby Brand L Niemann, 1983. large enough to result in a substantial contribution.

Table B-12.—Summary of Qualitative Evidence for Visibility-Related Values

Effect of increased visibility Affected groups Averaging timesa Supporting observationTransportation:More efficient, lower risk operations, visual

approach permittedIncreased opportunity to operate aircraft

Aesthetic:1) Social criteria:Decreased perception of air pollution

Options values; maintaining or increasingopportunity to visit less impaired naturaland urban settings

Improved view of night sky

2) Economic criteria:Increased property values

Enhanced enjoyment (user or activity values)of environment in:a) Urban settingsb) Natural settings

3) Psychological criteria:Existence values; maintaining pristine

environmentsLess concern over perceived health effects

Airport users, operatorscivilian and military

General aviation aircraft(noninstrument capablepilots, aircraft)

Substantial percentage ofgeneral population; urbanareas

Outdoor recreationists,campers, tourists

Amateur astronomers,other star watchers

Home owners

Urban dwellersOutdoor recreationists,

campers, residents ofnonurban areas

General population

General population, urbanareas

1-3 hr. readings

1-3 hr. readings

Daily to annual

Daily, peak visitationsummer months

Nightly

Long term

Long termDaily, peak visitation

summer months

Long term

Daily to long term

in

in

Visual approaches permitted when visibility>3-5 miles; airport specific (FAA, 1980b)

VFR permitted when visibility >3 miles (FAA,1980a)

Perception of air pollution in Los Angelessignificantly related to visibility for allaveraging times (Flachbert and Phillips,1980). Perception, annoyance significantlyrelated to particulate matter (Schusky, 1966)

Aggregate of activity values in iterativebidding studies suggests importance ofoptions values (Rowe and Chestnut, 1981)

Decrease in star brightness by fine particles(Leonard, et al., 1977)

Property values related to perception of airpollution, hence visibility (Rowe andChestnut, 1981; Brookshire, et al., 1979)

Willingness to pay for increased visibility inurban (Brookshire, et al., 1979) andnonurban settings (Rowe, et al., 1980)

Existence values may far outweigh activiuser values (Rowe and Chestnut, 1981)

About two-thirds of bid for improved visi

ty or

bilityin Los Angeles was related to concern overpotential health effects (Brookshire, et al.,1979)

aRepresents EPA staff judgment of most important averaging time based on supporting observatlon Because averaging times are related it IS difficult to specify single (long or short) averaging time as mostsignificant, Perception of visibility IS essentially instantaneous.

SOURCE: U.S. Environmental Protection Agency, “Review of the National Ambient Air Quality Standards for Particulate Matter,” EPA-45015-82-001, January 1982

246 ● Acid Rain and Transposed Air Pollutants: Implications for Public Policy

water directly from the atmosphere; this can cause fine-particle scattering to increase by a factor of 2 as rela-tive humidity increases from 70 to 90 percent. The an-nual mean relative humidity is greater than 70 percenteast of the Mississippi, and greater than 80 percent inMaine and several Atlantic coastal areas. Dense fog is,of course, most frequent in coastal and mountainousareas, with the northern Appalachian mountains, north-ern California coast, and Nantucket Island showing 50to 80 days/year of dense fog. Blowing dust is a signifi-cant cause of visibility impairment only in the south-ern Great Plains and Western desert regions.

On a regional or national basis, the frequency of rele-vant meteorological phenomena has been determinedby the National Oceanic and Atmospheric Administra-tion (NOAA) and individual researchers. However,reports from individual sites usually have not includedinformation on the occurrence of these natural phenom-ena during impaired visibility. Without such informa-tion, it is difficult to evaluate how much of observedvisibility degradation is due to natural causes.

Manmade

Anthropogenic particles contributing to reduced vis-ibility originate from stationary and mobile sources andmay be emitted directly or formed in the atmospherethrough transformation of such gaseous pollutants asS02. The origin and composition of fine particles (lessthan 2.5 pm) is generally different than that of large orcoarse particles. Fine particles tend to originate fromthe condensation of materials produced during combus-tion (e. g., lead) or atmospheric transformation of gases(e.g., sulfates). (See app. C, “Atmospheric Chemis-try. Atmospherically formed fine particles—partic-ularly sulfates—can circulate in moving air masses, andsubsequently be dispersed over large geographic areasfar from source regions. Since larger particles settle outmost rapidly, elevated levels of coarse particles usuallyoccur only near strong emissions sources.

Evidence for AnthropogenicallyCaused Decrease in Visibility

Both current and historical data bases can provideinsight into the relationship between manmade air pol-lution and visibility degradation.

Current information on amounts and location of S02

and NOX emissions can be related to the monitoringdata for air concentrations and deposition of sulfates andnitrates. In conjunction with meteorological data andvisibility measurements, this information allows detailedanalysis of factors contributing to short-term (e. g., sea-sonal) changes in visibility.

Historical visibility data can be used to infer long-term trends in air quality, because changing patternsof visibility reflect variation in natural and anthropo-genic emissions and meteorology over the long term.

General Conclusions

Based on: 1) current assessments of natural sulfursources and regional fine-particle levels, 2) long-termhistorical visibility data in the Northeast from 1889 to1950, and 3) examination of airport visibility trends afterdeleting data potentially influenced by natural sources(fog, precipitation, blowing dust), anthropogenic sulfatelevels appear to be the dominant component of Easternregional haze. Investigations over the past decade, usinga variety of data bases, show several areas of agreement:

●

●

●

●

Examination of airport data, pollution ‘measure-ments, and satellite photography indicates that re-gion-scale hazy air masses move across the East-ern United States and cause significant visibilityreduction in areas with little or no air pollutantemissions. In addition, aircraft measurement of theplumes of large powerplants, smelters, and majorurban areas have tracked the visibility impairmentby sources for 30 to 125 miles downwind.Light scattering by anthropogenic particulate pol-lution—of which fine sulfate particles are the mostimportant—appears to be the predominant causeof Eastern regional haze. Recent studies indicatethat sulfate in the Eastern United States is respon-sible for about 70 percent of visibility impairmentin the summer, and 50 percent on an annual basis.Nitrates rarely contribute substantially to visibilitydegradation in the East, while carbon particles ap-pear more important within urban areas than insuburban or rural areas.Contributions to visibility degradation in the Westappear to be more varied. Depending on the siteanalyzed, substantial contributions have beenshown for nitrates, carbon, sulfates, and dust.Analyses of the relationship between copper-smelteremissions and regional visibility degradation in theSouthwest, however, have shown correlations be-tween S02 emission levels and the percent of timeduring which reduced visibility occurs.Currently highest average visual ranges for theUnited States occur in the mountainous Southwest(annual visibility generally greater than 70 miles).Annual median risibilities east of the Mississippiand south of the Great Lakes are less than 15 miles,with the Ohio River Valley showing the lowest vis-ibility range (fig. B-15). While some of this dif-ference stems from lower relative humidity levelsin the West, a more important factor is the higherregional fine-particulate loadings in the East (e. g.,


Figure B-15.— Median Yearly Visual Range (miles) for Suburban and Nonurban Areas

Data from 1974-76 estimated from visual observations and other methods

SOURCE: J. Trijonis and R. Shapland, 1979: Existing Visibility Levels in the U. S.. Isopleth Maps of Visibility in Suburban/Nonurban Areas During 1974-76, EPA 450/5-79-010,U.S. Environmental Protection Agency, Research Triangle Park, N.C.

about 25 µg/m3 in the summer) than in the West(about 4 µg/m3 in the summer). (See fig. B-16.)National visibility maps show that summertime vis-ibility is much lower than annual-average visibilitylevels in the East, and that the largest regional gra-dients in visibility are found in California. InCalifornia, the two major pockets of impairedvisibility (Los Angeles Basin and southern San Joa-quin Valley) are due more to local- or medium-range transport than to long-range transport, whilein the East, the major area of impaired visibility(Ohio River Valley) is undoubtedly related to thehigh density of SO2 emissions. The cause of pocketsof impaired visibility found in the Gulf and mid-Atlantic coasts is less apparent, but probablyreflects a combination of natural and anthropogenicfactors.Trend analyses of visibility at Eastern airports forthe period of 1950-80 indicate that while winter-time risibilities improved in some Northeastern lo-

cations, overall regional visibility declined until1974, then slightly improved. However, summer-time, often the best season for visibility in the1950’s, is currently marked by the worst episodicregional haze conditions. * (See fig. B- 17. )From the early 1960’s through the mid-1970’s,U.S. control programs resulted in substantial re-ductions in total suspended particles (TSP) and S02

levels in most of the more polluted urban areas.However, during this same period, available infor-mation suggests that Eastern U.S. regional concen-trations of summertime fine particles, particularlysulfates, increased.

● \\’hlle ies than O 1 are air are i\+ at

p r e s e n t ent t substantially

99-413 0 - 84 - 17 : QL. 3


Figure B-16 .—Airborne Fine-Particulate Concentrations (µg/m 3) (summer 1977-81)

Mechanisms of Visibility Degradation

In a completely “pure”atmosphere, visual rangesacross the horizon can extend up to 200 miles; such con-ditions are occasionally approached on clear days in theSouthwestern United States. The extent of visibility deg-radation is determined both by the size and concen-tration of particles in the atmosphere. For example,adding 10 µg/m3 of coarse particles-greater than 2.5µm in diameter—to clean air would reduce visibilitymoderately, from 130 km to about 108 km. If, however,the particles were very small (in the optically criticalsize range of O. 1 to 1.0 pm), the addition of 10 µg/m3

would reduce visibility significantly, from 130 km toabout 44 km. (Table B-13 shows how the relative con-tribution of fine and coarse particles varies from loca-tion to location. )

Adding even low concentrations of substances topristine environments has a profound effect on visibility.The addition of 1 µg/m3 of fine particles to a clean at-mosphere can reduce visual ranges by about 30 percent.As the atmosphere is degraded, each additional incre-

ment of particulate matter has a smaller effect on visi-bility-adding 1 µg/m3 of fine particles to an atmospherewith a 20-mile visual range reduces visibility by only3 percent (see fig. B-18).

Two fine-particle components, hydroscopic (water-absorbing) sulfates and elemental carbon, generally tendto be most important in reducing visibility. In the East,sulfate compounds are the predominant component inthe fine particles causing light scattering over wideregions, while elemental carbon accounts for most lightabsorption in urban areas.

Fine particles between 0.1 and 2.0 µm diameter arethe most efficient at scattering light, and appear to ac-count for the bulk of visibility degradation due to lightscattering. * Sulfates and nitrates, the transformationproducts of S02 and NOX, exist in the atmosphereprimarily as particles ranging from 0.1 to 1.0pm in sizebefore being deposited to the earth in wet or dry form.

● Recent evidence suggests that at least some of the difference may be due shorter and less frequent episodes of elevated humidity during the 1950’s

than occurred in the 1970’s, C, Sloane, “Summertime Visibility Declines: Influences, ” Atmospheric 1983


c

n

.



Q

Q


Table B-13.—Characterization of Airborne Particulate.Matter Concentrations, 1977.81a

Figure B-19. —The Relationship Between RelativeHumidity and Light Scattering by Aerosol Sulfate

FPC

Long-term (6-12 months) average T S Pb (<2.5 µm)

Eastern locations:Undisturbed . . . . . . . . . . . . . . . . . . . . . . . 30-40 15-20Downtown . . . . . . . . . . . . . . . . . . . . . . . . . 60-90 20-30Industrial . . . . . . . . . . . . . . . . . . . . . .....60-110 25-45

Add Western locations:Undisturbed . . . . . . . . . . . . . . . . . . . . . . . 15-20 3-5Downtown , . . . . . . . . . . . . . . . . . . . . . ...75-130 15-25

West coast:Los Angeles area. . .................90-180 30-40Pacific Northwest . . . . . . . . . . . . . . . . . . 45-95 15-25aThe data used from the three networks include: EPA’s Inhalable Particulate Net-work, 35 urban sites, April 1980-March 1981; EPA’s Western Fine Particle DataBased, 40 nonurban sites, Summer 1980-Spring 1981; Electric Power ResearchInstitute SURE data base, 9 rural sites, 15 months, 1977-1978.

bTotal Suspended Particulates.cFine particulateSOURCE: Pace, T. G. (1981). Characterization of Particulate Matter Concentra-

tions. Memorandum to John Bachmann, Strategies and Air StandardsDivision, Office of Air Quality Planning and Standards (Dec. 30, 1981).

Figure B.18.— The Effect of Fine Particleson Visual Range

10 20 30 40

Fine particle concentration, µg/m -3

In clean areas (where visual range is greater than 200km), adding small quantities of fine particles to theatmosphere degrades visibility markedly; the sameincrement added to an area with low visibility has littleeffect.

SOURCE: U.S. Environmental Protection Agency, Protecting Visibity, An EPAReport to Congress, 1979.

The strong light-scattering properties of sulfate andnitrate particles are due to their affinity for water vapor;moreover, the greater the relative humidity of the at-mosphere, the greater the capacity of sulfate particlesto scatter light, especially when relative humidities riseabove 70 percent (see fig. B-19).

Measurement Techniques

The physics and chemistry of light scattering and ab-sorption is well understood. A variety of techniques isavailable to measure scattering and absorption with rea-sonable accuracy. The simplest of these involves esti-mation of visual range, using objects at specified dis-tances from an observer as reference points forestimating the distance beyond which distinct visual


phenomena cannot be observed. Such estimates are in-herently imprecise, and can be affected by such subjec-tive factors as the observer’s visual acuity. * However,the availability of such observations for a wide varietyof sites over a multiyear period—visual ranges have beenrecorded on a daily basis at hundreds of U. S. and Cana-dian airport sites in urban, suburban, and rural loca-tions since 1948—makes this data base indispensable forperforming time-trend analyses of visibility. Compari-sons of historical patterns for visibility in the EasternUnited States such as those in figure B-17 necessarilyderive from such data.

Telephotometry provides statistical measurementsanalogous to perceived visual ranges, while affordinggreater precision. The technique involves the use of atelescope capable of measuring the contrast between thebrightness of a faraway object and the horizon sky sur-rounding it. In addition, direct measurements of theportion of a light source lost to atmospheric interferenceare made with such devices as sun photometers, instru-ments to measure direct solar radiation intensity, andintegrating nephelometers. This last device passes a lightsource through a given air sample to determine howmuch light scattering occurs. While nephelometers arenot capable of measuring light absorption, and may dis-tort measurements as a consequence of air sample ma-nipulation, they are currently a widely used method ofmeasuring visibility, and are the primary means avail-able for determining how individual pollutants or pol-lutant mixes affect visibility. The nephelometer has beenthe basis for most of the experimental data relating causeand effect in visibility degradation studies.

No single measurement technique is adequate at pres-ent for assessing all significant factors involved in visi-bility impairment. The most productive areas of recentresearch have involved comparing two or more of theavailable monitoring techniques at selected sites or innew networks where fine particulate and meteorologicalmeasurements are made concurrently.

Until recently, visual-range/pollutant-concentrationstudies dominated the visibility literature; a number ofstudies completed over the past few years, however, haverelied on nephelometer and related measurements to de-termine correlations with pollutant levels. Imprecisionmay be introduced into either of these analytical tech-niques by discrepancies between pollution- and visibil-ity-monitoring locations, as well as by limitations inmeasurement techniques mentioned above. However,a large group of studies have found consistent patternspointing to sulfates as the major cause of regional-scalevisibility degradation.

“Prior to 1970, observations beyond 15 miles were not reported at moststat ions In the M Ideastern States The coarseness of dmtant observations in-creases with dwtance due to fewer available targets Visibifitles greater than

15 males are now estimated m mul[iples of 5 miles

Key Studies

A description of some of the key studies will illustratethree different ways researchers have used incompletedata to examine the visibility/sulfate relationship:

● the integrated use of multiple data bases,. specific case studies, and● modeling efforts.

Use of Multiple Data Bases: “Capita”

The most extensive analyses of spatial and temporalpatterns of visibility impairment in the Eastern UnitedStates have been performed by the Center for Air Pol-lution Impact and Trend Analysis (CAPITA).7 TheCAPITA analyses have used four historical data bases:airport visual range at 147 U.S. and 177 Canadian sitesfrom 1948 to 1980; Blue Hill Observatory visual-rangedata (3 mountaintops—32, 72, and 107 km from theobservatory) for 1889 to 1959; the NOAA/WMO** tur-bidity network of 25 to 35 sites during 1960 to 1975;and direct solar radiation intensity measurements atMadison, Wis., from 1920 to 1978. Significant findingsof the trend analysis were:

the region of lowest visibility in the 1970’s wasalong the Ohio River Valley;the strongest increase in haziness occurred in thesummer season in the States adjacent to the GreatSmoky Mountains (a decrease in annual averagevisibility of 15 to 6 miles since 1948);around the Great Depression, the visibility at BlueHill, Mass., improved, and two peaks of hazinessaround 1910-20 and 1940-50 coincide with twopeaks of coal- and wood-burning. Likewise, astrong peak in turbidity corresponding to a decreasein visibility was present in the Madison, Wis. , datacoinciding with the increase in national coal con-sumption. However, direct cause-effect relation-ships have not been established; andregional visibility in Eastern Canada and in boththe Eastern and Western United States apparentlyhas improved somewhat since 1972, but not to pre-1960 levels; whether this improvement relates tomore favorable meteorology or reflects the slightreduction achieved in particulate and S02 emis-sions in the last 10 years is unclear.

‘R B Husar, et al , “Spatial and Temporal Pattern of Eastern United StatesHaziness A Summary, ” report prepared by the Center for Air Pollution Im-pact and Trend Analysis, Washington Unwerstty, St Louis, Mo., for the U .SEnvironmental Protection Agency, 1981

* “National Oceanic and Atmospheric Administration/World Meteorologi-cal Organization


Case Studies: Southwestern United States

A number of factors combine to make visual rangesin the “four corners’ region of the Southwestern UnitedStates a promising means of assessing the effects of sul-fates on visibility. Pollutant concentrations and relativehumidity levels in most parts of Arizona, New Mexico,Colorado, and Utah tend to be quite low; consequently,visibility levels are among the highest known through-out the United States, and changes in pollutant concen-trations make significant differences in perceived vis-ual ranges. In addition, over 90 percent of the region’ssulfur emissions come from a single industry—coppersmelters—which experienced a total shutdown during1967-68, and a partial shutdown in 1980. However, amb-ient sulfate levels have not been monitored extensivelyin the region, as they have in the Eastern United States.Thus, while airport visual ranges show marked increasesin these four States during the two copper-smelter shut-downs, relationships between sulfate and visibility havebeen difficult to establish.

Initial investigations found substantial decreases insulfate levels at monitoring sites both near major smelt-ing operations, and at remote areas up to 300 miles fromthe major smelting area in southeast Arizona, duringthe 1967-68 shutdown. a Visibility conclusions from thisstudy have been criticized on the basis that sufficientdata were lacking to document a consistent sulfate/visi-bility relationship. During a second strike in the sum-mer of 1980, mean sulfate concentrations dropped toone-third of normal levels within 60 miles of the smelter;between 60 and 400 miles away, sulfate levels wereabout half of nonstrike conditions. Trajectory analysesof sulfate episodes in both the northern Great Plains andGrand Canyon areas show that some ultra-long-rangetransport from southern California occurs.

To further test the sulfate/visibility hypothesis, andto extend the information base on Southwestern visi-bility, an OTA contractor analyzed visual range andsulfate concentration data in 22 case studies coveringpollution episodes and nonepisode periods before, dur-ing, and following the two shutdown periods. In addi-tion, the RCDM long-range-transport model was usedto estimate sulfate levels more generally over the ‘‘fourcorners’ region, and to provide preliminary estimatesof the extent of sulfate contributions from sources out-side the four-State region for the period 1979-81. Theanalysis strongly confirms the relationship among cop-per smelter emissions, sulfate levels, and visual ranges;in addition, it suggests that substantial portions of thesulfate levels measured during the 1980 shutdown canbe traced to more distant sources, primarily those insouthern California.

‘J C. Trijonis, ‘ ‘Visibility in the Southwest: An Exploration of the Hlstorl-cal Data Base , Atmos. Environ. 13:833-43, 1979.

Modeling: Extinction Budget

While there are limitations in the use of regressionmodels for determining extinction budgets and aerosol/visibility relationships, these techniques show that over-all, sulfates account for over half (53 percent) of the ex-tinction budget, nitrates account for only 8 percent, anda significant part of the budget is not accounted for atmost of the sites analyzed. The nitrate contribution tothe extinction budget is very uncertain (but small) dueto uncertainties in the conventional nitrate filter-con-centration measurements. More comprehensive stud-ies of the extinction budget are needed, using specialair quality and visibility measurements rather than rely-ing on conventional air quality monitoring and airportdata.

Sulfate was known to contribute significantly to lightextinction 10 years ago. Subsequent efforts to determinethe relative importance of nitrate and carbon to visibilityimpairment were hampered by measurement techniquesand inherent spatial (urban v. rural) and temporal (sea-sonal) variability. There still is not enough high-qualitydata of nonsulfate measurements to generate completeregional budgets of the various pollutants’ contributionto visibility impairment. Most recent information sug-gests that carbon may contribute to light extinction inheavily urban areas, such as Houston (17 to 24 percentof light extinction), Denver (about 40 percent of lightextinction 10), and New York (35 percent of light extinc-tion”). Nitrate is an important factor in the West–e.g., in Riverside, Calf., it is responsible for about 20to 25 percent of light scattering.12 Nonetheless, at mostEastern U.S. sites, sulfate is the single most importantpollutant responsible for visibility degradation. Undertypical Eastern summertime conditions, sulfate accountsfor 70 percent or more of light extinction in the GreatSmoky Mountains,

13 the Shenandoah Valley,14 a n dDetroit, 15 On an annual basis, sulfates contribute anaverage of about 50 percent to visibility impairment inthe Eastern United States.l6

W. G, Dzubay, R. K. Stevens, C. W, Lewis, D. H. Hem, W. J. Courtney,J W. Tesch, and M, A. Mason, “Visibility and Aerosol Composition in Hous-t o n , T e x . , Environ Sci. Technof. 16:514-525, 1982.

‘“P. J. Groblicki, G. T. Wolff, and R. J, Countess, “Visibility-ReducingSpecies in Denver ‘Brown Cloud’ —I. Relationships Between Extinction andChemical Composition, ” Atmos. Environ. 15:2473-2483, 1981.

j !G, T, wolff, p. J, Groblicki, S. H. Cadle, and R. J. Countess, ‘‘particulate

Carbon at Various Locations in the United States, Particulate Carbon: At-mospheric Life Cycle, G. T. Wolff and R. L. Klimisch (eds. ) (New York:Plenum Press, 1982).

1’J. N. Pitts, Jr., and D. Grosjean, ‘ ‘Detailed Characterization of Gaseousand Size-Resolved Particulate Pollutants at a South Coast Air Basin Smog Re-ceptor Site’ (Springfield, Va.: National Technical Information Service, #PB302294, 1979).

13M, A. Fermm, G, T. Wolff, and N, A. Kelly, ‘‘The Nature mcf Sourceof Haze in the Shenandoah Valley/Blue Ridge Mountains Area, ‘J. Air Pol-lution Control Aawc. 31: 1074-1082, 1981,

1+R, K, Stevens, T. G, Dzubay, C. W. Lewis, and R. W. Shaw, Jr., ‘‘SourceApportionment Methods Applied to Determination of the Origin of AmbientAerosols That Affect Visibility in Forested Areas, Atmos, Environment (inpress).

15Wolff, et al, , op. cit.ICU,S Environment~ Protection Agency, Protecting Visibility, An EpA Re-

port to Congress, EPA 450/5-79-008, Research Triangle Park, NC., 1979,

App. B—Effects of Transported Pol lutants ● 2 5 5

B.5 HUMAN HEALTH RISKS*

Sulfur Oxides

National Ambient Air Quality Standards (NAAQS)have been established for gaseous sulfur dioxide (SO2),recognizing that it is harmful to human health in highconcentrations. The current primary standard for S02

is 365 µg/m3 (24-hour average concentration), a levelconsidered to pose no significant health risk. Thoughcurrently unregulated, concern also exists about healthrisks from sulfate particles—e. g., sulfuric acid and am-monium sulfate—that form through reactions betweenS02 and other substances in the atmosphere. Becausethese particles are extremely small (mostly under 1 µmin diameter), they can be transported over long distancesin the atmosphere and can readily be inhaled into thedeep passages of the lung.

Acute exposures to sulfates (greater than 315 µg/m3)constrict lung passages and lengthen lung clearance-times in humans and laboratory animals; chronic ex-posure of laboratory animals to sulfuric acid mist pro-duced evidence of the onset of chronic lung disease. Inaddition, numerous epidemiological studies have foundcorrelations between ambient sulfate concentrations andmortality rates. Adverse effects at current ambient levels(less than about 25 µg/m3) have not been directlyobserved.

Researchers at Brookhaven National Laboratory (un-der contract to OTA) have estimated that about 2 per-cent (a range of O to 5 percent) of the deaths per yearin the United States and Canada might be attributableto atmospheric sulfur-particulate pollution. The rangereflects uncertainties within the scientific communityabout the causal relationship between air pollution andmortality. Some researchers conclude there is a negligi-ble effect at prevailing sulfate concentrations, whileothers have found a significant association with mor-tality.

Sulfur Dioxide

S 02 emissions currently are regulated under theNAAQS of the Clean Air Act (CAA); the primarystandard for S02 is 365 µg/m3 (24-hour average con-centration). Air pollution episodes characterized by par-ticulate and very high levels of S02 have resulted inincreased deaths in people with preexisting heart andlung disease. Changes in the function of the lungs havebeen seen in sensitive groups at concentrations above

“This appendix IS based primarily on the OTA background paper ‘‘ Long-Range Transport kr Pollutlon Health Effects, ” Biomedical and EnvironmentalAssessment Divls.ion, Brookhaven National Laboratory, 1982

5,220 µg/m3. Recently, a study of asthmatics has shownthat constriction of bronchial passages during periodsof moderate exercise can occur at concentrations as lowas 1,300 and 260 µg/m3. 17

Experimental Evidence of Sulfate-RelatedHealth Damages

Once in the atmosphere, S02 is converted into sulfateparticles. Two main types of sulfate particles are knownto be produced: sulfuric acid (H2S04) and ammoniumsulfate [(NH4)2S0 4]. Both types of particles are ex-tremely small and may be inhaled deep into the lung.The high acidity of sulfuric acid particles make themof primary concern for medical researchers, althoughammonia in human breath may neutralize sulfuric acid.Ammonium sulfate has not produced the pulmonary ef-fects in animal and clinical studies that are seen withsulfuric acid mist.

In laboratory experiments, acute exposures to highconcentrations of sulfuric acid particles have a varietyof adverse health effects. Concentrations of about 750µg/m3 have irritated eyes and temporarily decreasedvision; concentrations of 350 µg/m3 have increasedbreathing rates and altered lung function in asthmatics.Changes in lung clearance rates have been observed inhealthy nonsmokers at concentrations of 100 µg/m3.Populations at special risk from particulate sulfates arethe elderly and adults with preexisting chronic heart orlung disease. Children also appear to be especially sus-ceptible to increased lower respiratory-tract illness anddecreased lung function. However, there is no direct evi-dence showing detectable effects on human health frommaximum likely environmental concentrations of sulfateparticles alone, although laboratory and chemicalstudies have verified that these small sulfate particlesconcentrate deeper in the lung than larger inhaled par-ticles. In addition, there is evidence that acid sulfates(and S02) render lung tissues more susceptible to thecarcinogenic effects of polycyclic organic matter.

Evidence of Sulfate-Particulate-RelatedHealth Damages

Substantial evidence has been gathered over morethan 30 years indicating injury from some aspect of thesulfate-particulate mix in air pollution. At high exposurelevels, sulfur-particulate air pollution can aggravate

17D Sheppard, A. Saishcs, J. A Nodel, and H A. Boushey, ‘ ‘Exerc ise In-

creases Sulfur Dioxide-Induced Bronchocons trlction in Asthmatic Subjects,A m Ret, Resp Lhs 123 :486 , 1981


asthma, chronic bronchitis, and heart disease.18 Therealso is evidence that sulfur-particulate air pollutioncauses increased acute respiratory disease in children.

Many analyses of cities with different air pollutionlevels, comparing death rates among specific popula-tion groups, or cohorts, have shown strong correlationsbetween pollution levels and mortality. Evidence isstrongest for correlation between acute episodic effectsand severe air pollution incidents; evidence of long-termeffects at comparatively low levels of pollution is morelimited and more controversial.

Nonetheless, scientists generally have been unable toattribute effects to any single element of the pollutionmix. During the early 1970’s, evidence seemed to pointto sulfate particles as the health-damaging agent in thesulfate-particulate mix. More recent evidence suggeststhat the combination of sulfates and other associatedparticles such as metallic ions, nitrates, and fine sootparticles may cause the observed effects.

Quantitative Estimates of Health Damages FromLong-Range Transport Air Pollutants

To derive quantitative estimates of damage causedby long-range pollution transport, Brookhaven NationalLaboratory used sulfate concentrations as an index ofthe sulfur-particulate air pollution mix, acknowledgingthat its use in this manner remains controversial, butit is the best indicator of health risk currently available.Several reports have discussed problems with the useof the sulfate surrogate model. They indicate that othersurrogates, e.g., respirable particles, may prove betterbut, at this time, the sulfur surrogate still remains areasonable choice, and possibly the best choice, for airpollution health effects risk assessment. A detailed studyby the Harvard School of Public Health for DOE con-cluded that a fine particulate (FP) measure would bepreferable, but ‘‘in the absence of FP data, . . . sulfatesmay be applied with caution. * The contractor useda previously developed health-damage function thatspecifically addresses uncertainties in knowledge by pro-jecting a range of mortality estimates for a given popula-tion exposure level. * *

1 sEnvironmentaf protection Agency, ‘ ‘Review of the National Ambient AirQuality Standards for Particulate Matter: Draft Staff Paper, ” Strategies andAir Standards Dwision OAQPS/EPA/RTP, Januaq 1982; Lester B. Lave andE P. Seskm, Air PolJution and Human Health, 1977, Johns Hopkins Univer-sity Press, Baftimore, Md. , Frederica Perera and A. K. Ahmed, RespirableParticles: impact of Airborne Fine Particulate on ffeafth and the Ersviron-ment (Cambridge, Mass.: Ballinger Publishing Co. , 1979).

“Spengler Final Report to DOE, October 1983, p. 5, and contsvbution ofSpengler and Evans at DOE/HERAP Workshop on Health Effects of Air Pol-lution, Brookhaven National Laboratory, August 1982.

● *The function, developed by Morgan et af., is a probabilistic one with a90-percent confidence interval of 0-11 excess deaths per 100,000 person-pg/m3sulfate exposure (i. e , deaths that would not occur in the absence of sulfate).M. G. Morgan, S. C Morris, A. K. Meier, and D. L. Shenk, “A Probabafis-tlc Methodology for Estimating Air Pollution Health Effects From Coaf-Fired

The health-damage function used is essentially a com-pilation of expert opinion about the relationship betweensulfate pollution and premature mortality (e. g., due toaggravation of preexisting respiratory or cardiac prob-lems). The range reflects a controversy over the validityof epidemiological (i.e., statistical) studies indicating arelationship between mortality and air pollution levels.It includes estimates from scientists who believe thereis a negligible effect at prevailing sulfate concentrationsas well as those believing there is a significantassociation.

These studies, carried out and extensively examinedover the past decade, examine mortality statistics fromareas of the country exposed to different levels of airpollution. The value of these studies is that they exam-ine human health directly, without the necessity of ex-trapolating from animal studies or small samples of peo-ple. They indicate that there are regional differences inmortality, and that regional patterns of mortality aresimilar to air pollution patterns. While it is possible thatfactors not considered in these analyses may be moreimportant than the sulfur-particulate mix, none havebeen demonstrated to date. Such studies are most usefulfor examining the potential effects of chronic, low-levelexposure—what might be happening and what mightresult from future air pollution levels.

The mortality estimates developed for OTA assumethat there is no damage threshold (i. e., minimum ex-posure level at which air pollution begins to affect mor-tality). If there is a threshold—which available medicalevidence neither confirms nor refutes— the mortalityestimates will decrease.

Sulfate-concentration data were derived from S02

emission inventories developed for the OTA study,using the Regional Climatological Dispersion Model(RCDM-2) developed at the University of Illinois–one of the models evaluated by the U. S, -CanadianWork Group on Transboundary Air Pollution. Popula-tion estimates and projections were derived from theU.S. Census Bureau and Canadian Ministry of Indus-try, Trade, and Commerce data.

Figure B-20 displays current State-by-State sulfate-exposure levels weighted by population. The map showsthat some of the Northeastern States with the highestpopulation density (e. g., New York, Pennsylvania, andOhio) also are exposed to the highest ambient sulfateconcentrations.

Estimates of excess deaths due to sulfate-particulateair pollution were made for: 1 ) 1980 population levelsusing 1978 emissions data; 2) populations in 2000, as-

Power Plants, ” Energy Systems and Pohcy 2:287-310, 1978. The current rangeof scientific judgment on the issue has not narrowed, but still spans the rangeof the 1978 subjective distribution (Morgan, M., et al., Technological Uncer-tainty in Policy Analysis, Report to the National Science Foundation, August1982).


Figure B-20.— Population Exposure to Airborne Sulfate (an indicator of potential health effects from sulfatesand other airborne particulate in each State)

suming that total emission levels are held constant at1978 levels; and 3) populations in the year 2000, assum-ing that sulfate-particulate levels are reduced by 30 per-cent from 1978 levels. Results of these three scenariosare presented in table B- 14.

Total pollutant emissions in the United States andCanada have been estimated to result in about 50,000premature deaths under the first scenario, increasing1978 mortality rates by about 2 percent—an amountapproximately equivalent to the number of deaths at-

tributable to infectious lung diseases. While increasesin population by 2000 would cause 1978 emissions levelsto induce slightly higher levels of premature deaths (sce-nario 2), a 30-percent decrease in the overall sulfate-par-ticulate mix by 2000 is estimated to reduce the numberof deaths annually attributable to air pollution to about40,000, or 1.6 percent of the total mortality rate.

Estimating mortality attributable to pollution expo-sure does not necessarily imply that the mortality im-pacts are the most significant. Mortality dose-response

.


Table B-14.—Summary of Scenario Results

Population Excess deaths Rate (deaths/10s

Scenario (millions) total (103 deaths) Range population)

1.1980 population, 1978 emissions, United Statesand Canada . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249 51 0-150 20.4

2.2000 population, emissions unchanged, United Statesand Canada . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291 57 0-170 19.8

3.2000 population, sulfate-particulate mix 30% below1978 levels, United States and Canada. . . . . . . . . . . . . . . . . . 291 40 0-120 13.8

SOURCE: Brookhaven National Laboratory, Biomedical and Environmental Assessment Division, “Long Range Transport Air Pollution Health Effects,” OTA contractorreport, May 1982.

functions are used because the available data on mor-bidi ty ( i l lness) are inadequate for detai ledepidemiological analyses.

Nitrogen Oxides

The term nitrogen oxides (NOX) refers to a numberof compounds—NO, N02, and such secondary byprod-ucts as nitric acid, nitrate aerosols, and nitrosamines*—all of which have the potential to affect human health.Of the several NOX compounds, by far the greatestamount is known about the effects of N02, a pollutantthat has been studied over the past 30 years and ispresently regulated under NAAQS.

The principal target of NOX pollution is the respira-tory system. Episodic or peaking concentrations of NO2

(possibly augmented by NO) have been shown to causeimmediate and short-term irritation to such sensitivesubgroups of the population as asthmatics and individ-uals recovering from acute respiratory infections.Chronic exposure to lower concentrations of N02 hasbeen associated with increased occurrence of acute res-piratory infections in infants and children. Some scien-tists have hypothesized that such repeated low-level ex-posures also are associated with chronic lung disease andincreased ‘ ‘aging’ of the lung in adolescence andadulthood.

Health effects directly attributable to NO2 generallyare considered to result from localized sources of pol-lution. Combustion of coal, oil, and gasoline is estimatedto be responsible for local outdoor concentrations ofNOX 10 to 100 times naturally occurring backgroundlevels in areas of high emissions.** Indoor sources ofNOX, such as gas cooking stoves, some home heatingsystems, and cigarette smoking, also are known to con-tribute to population exposure, and in some cases mayexceed outdoor concentrations of NO,.

● These secondary byproducts are produced from photochemical transforma-tion of NO and NOZ in the atmosphere; nitrosamine formation has beentheoretically suggested but not conclusively proven.

● ● Mobile-source combustion was estimated to contribute 44 percent of an-thropogenically produced NO, for 1976 in the United States, whife stationary-source combustion accounted for 56 percent. USEPA, Air Quality Criteria forOxides of Nitrogen, June 1979, pp. 1-2 and 1-3,

Byproducts of NOx are known to be transportedover long distances, contributing to acid deposition andozone formation. Some of these secondary pollutants aremore toxic on a per-unit basis than N02; however, itis not currently known whether they are present in suf-ficient concentrations—or persist long enough—in theatmosphere to endanger human health. Recent studiesperformed for the EPA and the National Academy ofSciences suggest that nitrosamines and similar chemi-cal species may be found in sufficient concentrations inpolluted urban air near certain industrial areas to war-rant concerns for health. Not enough is known yet aboutthe effects of NOX, or their concentrations in theatmosphere, to permit quantitative estimation of thehealth-related damages for which NOX may be respon-sible, or of the population at risk from these pollutants.

Summary of Medical Research

Clinical studies of the short-term effects of NOx onhuman volunteers have been conducted on asthmatics,patients with bronchitis, and healthy subjects. Thestudies generally have shown that the sensitivity ofasthmatics to irritants such as cold air or air pollutantscan be heightened by short-term concentrations of NO2

as low as 940 µg/m3 (the primary NAAQS for N02 is100 µg/m3 annually; there is no shorter term standard).Recovery from these effects tends to be rapid, and itis not known whether repeated exposures of this kindhave any cumulative effects or predispose the lungs topermanent damage. Most studies do not show increasedsensitivity or irritation in either healthy or bronchitissubjects when NO2 concentrations are at or below 2,820µg/m 3.

Laboratory experiments have tested the reactions ofanimal tissues to similar and higher concentrations ofN02. These experiments have provided significant in-sight into the mechanisms that govern human reactionsto NO2 exposures, and suggest more serious conse-quences of long-term human exposure to NO2 than haveappeared in short-term clinical studies.

Prolonged exposure to N02 has been observed tocause damage to lung tissue in laboratory animals. Theprincipal consequences of such damage appear to be de-


velopment of emphysema-like conditions and reductionsin resistance to respiratory infection. For a fixed dosage,greater concentrations have been shown to cause greaterincreases in mortality rates for animals exposed to res-piratory infection than greater duration of exposure.This suggests that fluctuating levels of N02, such as arefound in community air, may prove more toxic thansustained levels of the gas.

Epidemiologica1 studies of populations of children ex-posed to N02 concentrations, primarily via indoor airpollution, confirm laboratory findings of reduced resis-tance to respiratory infection in exposed animals. Chil-dren exposed to additional quantities of NO2 (and pos-sibly NO) from gas stove combustion—in particular,infants under the age of 2—show significantly greaterincidence of acute respiratory illness and changes in lungfunction than counterparts living in homes with elec-tric stoves. Similar findings have not been observed inadults.

IndirectAcid

Health EffectsPrecipitation

Acidified waters are known to be capable of dissolv-ing toxic metals—e. g., aluminum, copper, lead, andmercury-and releasing such toxic substances as asbes-tos, from soils and rocks in watersheds and lakes, andfrom drinking water distribution systems. Researchersare attempting to determine the extent to which the totalbody burden of these substances in humans might re-sult from acidic deposition, as opposed to direct inhala-tion or occupational exposure.

No direct relationship has yet been established be-tween acid deposition and degradation of drinking-waterquality. Potentially harmful levels of asbestos and lead,however, have been found in “aggressive’ (i. e., cor-rosive) acidified waters in the Eastern United States.Scientists have encountered difficulty in pinpointing thedirect source of concentrations of toxic materials foundin acidic tap waters. Acidic precipitation can scavengetoxic materials from the atmosphere during rainfallevents, leach them from soils and rocks as they passthrough the watershed, or leach them from pipes andconduits used to distribute water to users.

The aggressiveness of municipal water supplies canbe monitored and corrected fairly easily. A recentamendment to the National Interim Primary DrinkingWater Regulations has established the initial steps ina corrosion control program.19 Public water systems arenow required to identify the presence of specific mate-

19~nY.lrOnmen(~ p r o t e c t i o n A g e n c y , I n t e r i m Pnmar-y Drmkmg Water Reg-

ulat Ions, Amendment Final Rule, Fed. Reg 45( 168). 57332-57357, Aug 27,1980

rials (e. g., lead and cadmium) within the distributionsystem and to monitor corrosiveness characteristics forat least 1 year. Also, the types of materials used in thedistribution system and home plumbing must be re-ported.

A recent study sponsored by EPA20 of 119 surface wa-ter supplies in the 6 New England States indicates that84 to 92 percent of the water bodies are highly aggres-sive. Anti-corrosion treatment is currently practiced inspecific areas (e. g., Boston) where acid precipitation isknown to affect water quality. * However, aggressivewell water in rural areas where soils have little capacityto counteract acid deposition is more difficult to detectand mitigate, and potential health effects remain ofconcern.

Asbestos

Asbestos occurs widely in natural rock formationsthroughout the east and west coasts of the United States.In addition, asbestos fibers are mixed in concentrationsof 10 to 25 percent with cement to reinforce pipe usedto distribute water supplies. While studies have shownthat water can corrode asbestos-cement materials andrelease fibers into the drinking water, data showing adirect association between precipitation pH and asbes-tos content of drinking water are not available. How-

t ever, preliminary estimates of asbestos in drinking wa-ter from asbestos/cement distribution pipes suggest thatapproximately 11 percent of the total U.S. populationis exposed to asbestos concentrations greater than 10million fibers/liter.21

Correlations between above-average incidence of cer-tain abdominal cancers and elevated concentrations ofasbestos in drinking water recently have been found inthe San Francisco Bay area, where abundant naturalsupplies of asbestos occur in bedrock.22 EPA has useddata from studies of workers exposed to airborne asbes-tos to estimate that one additional cancer will be causedfor every 100,000 people exposed to drinking water con-taining 300,000 asbestos fibers/liters for 70 years.**

20 Flovd B. ‘1’aylor, ‘ ‘Impact of Acid Rain on Water Supplies in Terms ofEPA Drinking Water Regulations, ’ Proceedings of the Amerscan iVater J$’orksAssociation, Las Vegas, June 1983, In press

“Boston has a high percentage of lead service lutes and plumbmg. During1976-77, prior to pH adjustment, 44 percent of the top water samples exceededthe maximum contaminant level (MCL) of 0.05 mg/1 lead.

“J R Millette, M. F. Pansing, and R. L Boone, “Asbestos-Cement Ma-terials Used in Water Supply,, Water Engineering and Management, 128:48,51, 60, 97, 1981

~2M, S Kanarek, p. M Con fortl, L A. <Jackson, R. C. Cope I_, and J ~Murchio, ‘ ‘Asbestos in Drmkmg Water and Cancer Incidence m the San Fran-c isco Bay Area, Am j .Epldemml , 112 54-72, 1980.

*“Federal Register 44(191) 56634, Oct 1, 1979


Lead

Lead enters aquatic ecosystems from wet and dry pre-cipitation, mineral erosion, street runoff, leaded gaso-line, and municipal and industrial discharge, as well asfrom corrosion of lead in pipes and plumbing systems.Corrosion of lead from lead-containing materials isfacilitated by waters of low pH (less than 6.5) —espe-cially when the waters are also of low alkalinity. In-dividual water samples in isolated areas characterizedby low pH values have shown lead concentrations of upto 100 times the 50 µg/1 ambient water quality stand-ard.23 Early morning water samples from New Englanddistribution systems showed 7 percent exceeded thestandard for lead. 24

While elevations in human blood lead levels will re-sult directly from ingesting contaminated drinking wa-ter, the human body also absorbs lead from a numberof other sources, including food, ambient air, cigarettes,paint, dust, and dirt. *

Mercury

Studies in Scandinavia, Canada, and the UnitedStates have found correlations between elevated levelsof mercury in fish and increasing acidity of lake andstream habitats. However, no cases of mercury poison-ing are known to be associated with freshwater fish inthe United States. Lakes in acid-sensitive regions ofMinnesota, Wisconsin, and in the Adirondacks of NewYork have yielded fish with mercury concentrationsabove the FDA public health standard of 0.5 ppm.25 26

Studies are currently under way to assess correlationsbetween observed mercury levels and lake pH levels.

A number of recent efforts to neutralize acidic lakesthrough the application of lime appear to be successful

23P, Mu~hak Multimedia Pollutants. Report to the National Commission

on Air Quality, ’Contract No, 232-AQ-6981, 1981; G. W. Fuhs and R. A, 01-sen, ‘ ‘Technical Memorandum: Acid Precipitation Effects on Drinking Waterm the Adirondack Mountains of New York State, New York State Dept, ofHealth, Albany, N, Y,, 1979.

2+ Tav]or, F, B , OP. cit

“EPA has defined approximately 2.5 million people-inner-city childrenunder 5 and pregnant women—as being at special risk from elevated levels oflead in the bloodstream While aggressive drinking waters can leach lead frompipes and contribute to lead levels in the blood, such effects may constitutea greater threat to rural populations using acidified groundwaters than to ur-ban populations using waters that can be treated readily, Preliminary investiga-tions m the New York State Adirondacks region have found isolated cases ofhuman exposure to lead-contaminated drinking water resulting in lead con-centrations in blood as high as 59 pg/dl. (Blood lead levels should be main-tained below 30 pg/dl to avoid deleterious heafth effects, ) New York StateDepartment of Health, Technical Memorandum: “Lead Poisoning Relatedto Private Drinking Water Sources, Oct. 23, 1981.

lsAcld Precipitation in Minnesota, Minnesota po]]ution control AgmCy,Minnesota Department of Natural Resources, Minnesota Department ofHeafth, Jan. 26, 1982, pp. 7-67; Letter from G. Wolfgang Fuhs, Director, NewYork State Department of Health, to Congressman Toby Moffett, July 16, 1980,p. 3.

lfJper~[)na] C[)nlmunlcatlon, James Wiener, U. S. Fish and Wildlife Service,

La Crosse Field Research StatIon, La Crosse, Wis,, May 1982,

in reducing mercury levels in fish. Favorable resultshave been reported for various locations in Sweden, andfor Nelson Lake in Ontario, Canada.27

Other Metals

Acidified waters are known to leach substantialamounts of aluminum from watersheds, and thevolubility of aluminum increases as pH decreases below6.0. Concentrations of aluminum in acidified well wa-ter in the United States have been found as high as 1.7mg/1, which could represent a substantial portion of anindividual’s daily aluminum intake. Little is knownabout the toxicity of aluminum to most human popula-tions; no restrictions have been established in the UnitedStates on aluminum concentrations in drinking watersor foods.

Several studies have shown, however, that elevatedaluminum concentrations may be toxic to individualswith impaired kidney function—e. g., water containingmore than 50 µg/1 of aluminum is thought to be unsafefor dialysis treatment. Sixty-one percent of surface wa-ter samples in New England contained aluminum equalto or greater than 100 µg/l; 24 percent exceeded 200µg/l. 28

For normal human beings, copper deficiency is morewidespread than copper toxicity. A limit of 1 mg/1 forcopper concentration in U.S. drinking water has beenset on the basis of taste; no regulatory limit exists forcopper concentrations in food. Acidic waters have beenshown to be capable of corroding copper from pipes inhousehold distribution systems—elevated copper levelshave been reported in several drinking water samplesfrom sensitive areas of the Adirondacks. *g Additionally,a recent survey of New England distribution systemsshowed 29 percent of early morning water samples ex-ceeded the standard for copper .30 While several casesof copper toxicity have been reported in the UnitedStates among individuals with Wilson’s disease, a once-fatal disorder of copper metabolism, the hazard to thegeneral population from currently observed copperlevels appears quite small.

In its natural state, cadmium occurs as an impurityin zinc, copper-zinc, or lead-zinc deposits. In concen-trated or pure form it is very toxic. Little evidence ofcadmium corrosion from galvanized pipe or plumbingalloys currently exists, although studies of municipal wa-

27’’ The Role of Clouds in Atmospheric Transport of Mercury and OtherPollutants, ” G. H. Tomlinson, R. J. P. Brouzes, R. A, N, McLean, and JohnKadlecek, m Ecological Impact ofAcid Precipitation, Proceedings of an Inter-national Conference, Sandefjiord, Norway, Mar, 11-14, 1980, Oslo-As.

28 Tay]or, F. B. , op. cit.

“(;. W. Fuhs and R. A. Olson, ‘ ‘Technical Memorandum: Acid Precipita-tion IMIects on Drinking Water in the Adirondack Mountains of New York,New York State Department of Heafth, Albany, 1979.

‘FI’aylor, F, B, op. c i t .


ter systems have shown levels to occasionally exceed the trial exposure conditions. Based on the infrequentU.S. health standard of 10 µg/1. The concentrations occurrence of cadmium in drinking water at levels abovefound in drinking water, however, represent only a min- 10 µg/1, such exposures are not considered a threat toute fraction of the amounts known to cause acute cad- many people.mium poisoning or chronic health effects under indus-

B.6 ECONOMIC SECTORS AT GREATEST RISK FROMCONTROLLING OR NOT CONTROLLING

TRANSPORTED POLLUTANTS

Throughout this report, five sectors of the U.S. econ-omy have been identified as sensitive to the potentialeffects of decisions to control or not to control trans-ported air pollutants: 1) farming and agricultural serv-ices, 2) forestry and related products, 3) coal mining,4) freshwater fishing-related recreation, and 5) the elec-tric utility industry. This appendix presents informa-tion about the magnitude and geographic distributionof these activities in the Eastern 31 -State region. OTAassembled data from the Department of Labor, the U.S.Fish and Wildlife Service, and the Edison Electric In-stitute to estimate levels of economic activity for each,and levels of participation, where appropriate, in recentyears. These tabulations are of total income, expendi-tures, employment, and resource utilization for a givensector. They are provided to indicate the relative im-portance of each sector to the economy and people ofthe Eastern 3 1-State region, not as estimates of the num-ber of people or amount of economic activity that mightbe affected by decisions regarding transported airpollutants.

The amount of available information on the poten-tial effect of controlling or not controlling transportedair pollutants varies substantially among sectors. More-over, for sectors dependent on resources potentially sus-ceptible to transported pollutants, reliable estimates ofthe financial losses associated with resource damage can-not presently be attempted, even for resources for whichdamages can be estimated. Estimates of losses in cropproduction from ozone, and of the potential suscepti-bility of aquatic resources and forests to acid deposition,are provided in chapters 3 and 5, and are treated in de-tail in appendix B, section 2. Estimates of the econom-ic effects of emissions control on coal mining and elec-tric utilities, and of the coal-mining employment effectsof emissions controls, are also presented in chapters 3and 5, and detailed in appendix A. In general, the costsassociated with emissions controls are better known thanthose associated with potential resource damage. As

the available measures of potential effects are expressedin different forms, and represent disparate levels ofknowledge, they cannot be compared directly across thefive sectors. However, the importance of the economicsectors themselves can be compared, both in monetaryand participatory terms, as well as among sectors andStates.

Table B-15 presents State-by-State estimates of thepersonal income and expenses for which the five sec-tors directly account, in millions of dollars and as a per-centage of the state total. U.S. Department of Labordata on wages, salaries, and proprietary income, aver-aged over the years 1978-80, are presented for farmingand agricultural services, forestry and related products,and coal mining. Freshwater fishing-related recreationexpenses are compiled from U.S. Fish and WildlifeService survey data on expenditures for travel, lodging,food, fees, and light equipment used exclusively for fish-ing in 1980. For electric utilities, data from the EdisonElectric Institute on the percentage of personal incomespent on residential electricity consumption in each Stateare provided.

Farming- and forestry-related income each accountfor slightly less than 2 percent of the Eastern U.S. re-gion total, or an average of $21.8 billion and $20.5 bil-lion, respectively, for the 1978-80 period. Intraregionalvariations are significant: farming and agricultural serv-ices accounted for over 3 percent of personal income inKentucky, Mississippi, Missouri, North Carolina, Ver-mont, and Wisconsin, and over 5 percent in Arkansas,Iowa, and Minnesota. Similarly, forestry, lumber,wood, and paper products accounted for over 3 percentof personal income in Alabama, Georgia, Minnesota,Mississippi, New Hampshire, South Carolina, Ver-mont, and Wisconsin, over 5 percent in Arkansas, andover 10 percent in Maine.

The greatest regional variation is found in the distri-bution of income due to coal mining, which accountedfor an average of nearly $7 billion in the region during


Table B.15.-lncome or Revenues From Farming, Forestry, Coal, Fishing, and Utilities(in millions of dollars per year and percent of State total income)

Forestry, lumber, FreshwaterFarming and wood, and fishing-related Utility revenues

agriculture services paper products Coal-mining recreation (residential only)

Region/State Income Percent Income Percent Income Percent Expenses Percent Revenues Percent

New England:Maine. . . . . . . . . . . . . . . . . . 110.2New Hampshire . . . . . . . . . 27.3Vermont . . . . . . . . . . . . . . . 131.1Massachusetts. . . . . . . . . . 48.9Rhode Island . . . . . . . . . . . 20.4Connecticut . . . . . . . . . . . . 35.1

1.70.54.30.10.30.1

678.2208.1103.6687.9

58.2272.0

10.53.63.41.60.91.0

0.3

0.00.30.00.0

0.00.00.00.00.00.0

83.636.232.186.312.061.3

1.30.61.10.20.20.2

179.7166.881.2

830.0135.6543.8

2.92.92.81.92.22.1

Middle Atlantic:New York . . . . . . . . . . . . . . 719.0New Jersey. . . . . . . . . . . . . 231.7Pennsylvania . . . . . . . . . . . 951.3

0.50.41.1

1,349.4846.2

1,331.1

1.01.51.6

1.5—

1,215.3

0.0—1.4

240.899.2

272.7

0.20.20.3

2,322.41,294.41,784.2

1.72.32.2

East North Central:Ohio . . . . . . . . . . . . . . . . . . . 911.0Indiana . . . . . . . . . . . . . . . . 1,017.1Illinois . . . . . . . . . . . . . . . . . 1,805.7Michigan . . . . . . . . . . . . . . . 779.9Wisconsin . . . . . . . . . . . . . . 1,424.8

1.12.51.91.04.2

1,123.7641.7

1,005.3767.7

1,520.4

1.41.61.11.04.5

481.5210.3564.5

1.30.2

0.60.50.6

0.0

280.2268.7321.5394.9440.5

0.40.70.40.61.4

1,737.4839.0

1,690.01,197.4

641.5

2.22.21.91.72.0

West North Central:Minnesota. . . . . . . . . . . . . . 1,664.0lowa . . . . . . . . . . . . . . . . . . . 1,670.7Missouri . . . . . . . . . . . . . . . 1,308.3

5.38.13.7

2.30.00.91.20.53.81.72.12.7

1,109.2171.4416.4

3.50.81.2

1.28.7

54.5

0.00.00.2

383.5111.6301.6

1.30.60.9

504.8481.3807.9

1.72.52.4

South At/ant/c:Delaware . . . . . . . . . . . . . . .Washington, D. C.. . . . . . . .Maryland . . . . . . . . . . . . . . .Virginia . . . . . . . . . . . . . . . .West Virginia . . . . . . . . . . .North Carolina . . . . . . . . . .South Carolina. . . . . . . . . .Georgia . . . . . . . . . . . . . . . .Florida. . . . . . . . . . . . . . . . .

116.23.4

265.9426.452.8

1,410.9304.2760.0

1,564.5

0.0 0.0—0.11.6

15.00.00.00.00.0

7.83.7

61.1174.1100.5209.3135.7300.8483.9

0.20.00.20.50.90.60.80.90.8

11.6229.6499.5

1,075.8266.8

1,043.7548.4903.2

2,377.3

2.31.71.73.02.42.93.12.64.1

—0.9

261.1681.8104.6984.1566.3

1,149.7736.4

—0.00.91.90.92.63.13.21.3

—28.2

583.71,747.3

3.30.61.91.3

East South Central:Kentucky. . . . . . . . . . . . . . . 757.5Tennessee . . . . . . . . . . . . . 418.5Alabama ., . . . . . . . . . . . . . 661.3Mississippi . . . . . . . . . . . . . 650.9

West South Central:Arkansas . . . . . . . . . . . . . . . 1,042.0Louisiana . . . . . . . . . . . . . . 506.4

3.51.52.95.0

299.0639.8979.9564.3

1.42.34.34.4

1,532.0135.2389.2

0.1

7.00.51.70.0

235.8268.5285.8170.3

1.11.01.31.4

511.9872.2765.5434.5

2.53.23.53.5

8.41.9

1.9

639.2644.2

20,541.6

5.12.4

1.8

7.10.1

6,969.7

0.10.0

0.6

237.9224.3

6,326.2

2.00.80.6

384.8717.5

3.32.6

25,980.3 2.3SOURCES: U.S. Department of Labor; U.S. Fish and Wildlife Service, Department of the Interior; Edison Electric Institute,

Eastern 31-State total . ...21.797.2

1978-80, or 0.6 percent of the total. Nearly two-thirdsof this income was earned in Kentucky, Pennsylvania,and West Virginia; coal mining accounted for over 1percent of personal income in Alabama, Pennsylvania,and Virginia; 7 percent in Kentucky; and 15 percentin West Virginia.

Expenditure data for electrical power show that resi-dential consumers spent nearly $26 billion to purchaseelectricity in the region in 1980. In general, the pro-portion of income spent on electricity is higher in South-ern States, reflecting greater use of electrically powered

cooling equipment. As a proportion of personal income,expenditures range from a low of 1.7 percent in theDistrict of Columbia, Maryland, Michigan, Minnesota,and New York, to a high of 4.1 percent in Florida.

Freshwater fishing accounted for expenditures of ap-proximately $6.3 billion in the region in 1980, or 0.6percent of the region’s total personal income. States inwhich these expenditures exceeded 1 percent of personalincome included Alabama, Arkansas, Kentucky,Maine, Minnesota, Mississippi, Tennessee, Vermont,and Wisconsin. As shown in the table, freshwater fishing


generated at least $250 million in 1980 expenditures in12 States: Alabama, Florida, Georgia, Illinois, Indiana,Michigan, Minnesota, Missouri, Ohio, Pennsylvania,Tennessee, and Wisconsin.

Table B-16 presents Department of Labor estimatesof the number of people employed in farms and agri-cultural services, forestry and related products, and coalmining in 1980. In the Eastern region overall, agricul-ture employed slightly over 3 million people, or 4 per-

cent of the regional total. Variations within the regionare substantial—agriculture employed over 5 percentof the work force in Alabama, Indiana, Minnesota, Mis-sissippi, Missouri, North Carolina, South Carolina,Tennessee, Vermont, and Wisconsin; and over 10 per-cent of the work force in Arkansas, Iowa, and Kentucky.

Total Eastern employment in forestry, lumber, woodand paper products was slightly over one million, or 1.4percent of the regional total. These industries employed

Table B-16.—Number of People Employed in Farms and Agricultural Services,Forestry and Related Products, and Coal Mining in 1980

Farms and Forestry, lumber, andagricultural servicesa wood and paper productsb Coal mining

Percent of Percent of Percent ofNumber of people State total Number of people State total Number of people State total

..- . . . --- ---4.3 1,404,000 1.0 251,000 0.2

————

—

——

0.1——

0.7

0.30.2—

0.3—

——

0.0

0.7———

3,1————

0.20.78.60.3

us. total . . . . . . . . . . . . .

New England:Connecticut . . . . . . . . . . .Maine . . . . . . . . . . . . . . . .Massachusetts . . . . . . . .New Hampshire . . . . . . .Rhode Island . . . . . . . . . .Vermont . . . . . . . . . . . . . .

Mideast:Delaware . . . . . . . . . . . . .District of Columbia. . . .Maryland . . . . . . . . . . . . .New Jersey . . . . . . . . . . .New York . . . . . . . . . . . . .Pennsylvania . . . . . . . . . .

Great Lakes:Illinois . . . . . . . . . . . . . . .Indiana . . . . . . . . . . . . . . .Michigan . . . . . . . . . . . . .Ohio . . . . . . . . . . . . . . . . .Wisconsin . . . . . . . . . . . .

Plains Region:lowa . . . . . . . . . . . . . . . . .Minnesota . . . . . . . . . . . .Missouri . . . . . . . . . . . . . .

Southeast:Alabama . . . . . . . . . . . . . .Arkansas . . . . . . . . . . . . .Florida . . . . . . . . . . . . . . .Georgia. . . . . . . . . . . . . . .Kentucky . . . . . . . . . . . . .Louisiana . . . . . . . . . . . . .Mississippi . . . . . . . . . . .North Carolina. . . . . . . . .South Carolina . . . . . . . .Tennessee . . . . . . . . . . . .Virginia. . . . . . . . . . . . . . .West Virginia. . . . . . . . . .

4,628,300

20,436C

23,06925,670C

7,9873,121

15,220

7,116161

38,29330,570

117,351118,613

168,380134,314116,823154,279163,400

177,130161,453165,696

101,110103,621135,023119,319154,21272,610

104,257177,55676,427

144,397100,66630,607

1.34.40.91.80.76.1

11,87232,18833,395C

11,066C

3,9016,409

0.76.21.22.50.92.6

————

—

4,082C

384C

13,82438,59964,96563,580

2.40.01.90.91.52.2

1.40.10.71.10.81.2

1,049——

37,911 C

3.15.33.13.27.2

47,07932,79132,21852,40468,842

0.91.30.81.13.0

18,1476,060

15,490

12.37.67.2

8,46443,41523,910

0.62.01.0

——

1,049

6.010.63.24.6

10.03.99.66.15.16.73.84.1

4.0

49,05634,10439,19159,37516,74928,51631,21857,19130,15037,10638,351

7,350

1,020,724 (73%)d

2.93.50.92.31.1

2.92,02.01.71.41.0

1.4

12,539

—47,319

———

4,18419,10764,096’

227,252 (91%)dEastern 31-State total . . 3,010,885 (65%)d

aIncludes farm proprietors; excludes manufacture and sale of farm equipment.blncludes construction of prefabricated buildings and mobile homes; excludes manufacture of furniture, printing and publishing industries, and Sale of building materials,c1980 data not available for all data points—estimates may be slightly low due to use of data from mid-1970’sdFigures in parentheses represent the proportion of the U.S. total employed within the Eastern 31-state region.

SOURCE: U.S. Department of Labor.

99-413 0 - 84 - 18 : QL. 3


2 percent or more of the work force in Alabama, Geor-gia, Minnesota, Mississippi, New Hampshire, NorthCarolina, South Carolina, and Vermont, and 3 percentor more in Arkansas, Maine, and Wisconsin.

Employment in coal mining is the least evenly dis-tributed of those sectors surveyed. It accounted forslightly under a quarter-million jobs, or 0.3 percent ofthe Eastern U.S. work force, in 1980. Coal mining em-ployed greater than 0.5 percent of the work force in Ala-bama, Pennsylvania, and Virginia, and employed 3.1and 8.6 percent of the work force in Kentucky and WestVirginia, respectively. Estimates of shifts in coal min-ing employment that might accompany stricter SO2-emissions controls are presented in appendix A.

The 1980 National Survey of Fishing and Hunting

conducted by the Fish and Wildlife Service is the basisfor estimates in table B-17 of the number of participantsin freshwater fishing in the Eastern region. Countingonly in-state fishing participants, to avoid double count-ing, over 21 million people are estimated to have takenpart in freshwater fishing, devoting an average of some-where between 11 and 21 days per year to this form ofrecreation. Counting only in-State residents, Florida,Georgia, Illinois, Michigan, Minnesota, New York,Ohio, Pennsylvania, and Wisconsin each had over amillion freshwater-fishing participants; when out-of-State anglers are included, Alabama, Indiana, Ken-tucky, Missouri, North Carolina, and Tennessee areadded to this list.

Table B-17.-Number of Residents and NonresidentsParticipating in Freshwater Fishing in 1980a

Number of Total numberresidents of participants

Alabama . . . . . . . . . . . . . .Arkansas. . . . . . . . . . . . . .Connecticut . . . . . . . . . . .Delaware . . . . . . . . . . . . . .District of Columbia . . . .Florida. . . . . . . . . . . . . . . .Georgia . . . . . . . . . . . . . . .Illinois . . . . . . . . . . . . . . . .Indiana . . . . . . . . . . . . . . .lowa. . . . . . . . . . . . . . . . . .Kentucky. . . . . . . . . . . . . .Louisiana . . . . . . . . . . . . .Maine . . . . . . . . . . . . . . . .Maryland . . . . . . . . . . . . . .Massachusetts. . . . . . . . .Michigan . . . . . . . . . . . . . .Minnesota. . . . . . . . . . . . .Mississippi . . . . . . . . . . . .Missouri . . . . . . . . . . . . . .New Hampshire. . . . . . . .New Jersey . . . . . . . . . . .New York . . . . . . . . . . . . .North Carolina . . . . . . . . .Ohio. . . . . . . . . . . . . . . . . .Pennsylvania . . . . . . . . . .Rhode Island . . . . . . . . . .South Carolina. . . . . . . . .Tennessee . . . . . . . . . . . .Vermont . . . . . . . . . . . . . .Virginia . . . . . . . . . . . . . . .West Virginia . . . . . . . . . .Wisconsin. . . . . . . . . . . . .

874,952574,351271,488

30,22110,361

1,193,5831,117,5441,264,434

913,212592,242734,630752,110214,505268,716333,680

1,292,6821,175,026

538,349998,667115,357229,175

1,036,257927,341

1,412,0221,168,907

60,143490,089903,633113,256637,681341,293

1,109,73821,760,645

1,117,099895,619307,217

35,13615,006

1,550,4061,253,2651,401,9221,111,095

646,1801,052,587

955,567364,062321,687414,012

1,666,2951,639,131

689,9011,230,423

224,998383,375

1,225,3131,096,3381,500,5251,400,689

72,633639,259

1,161,467182,753823,369416,874

1,674,219bEastern 31-State total . .

aDoes not include fishing In the Great Lakes.bTotal not calculated due to potential double-counting of participants.SOURCE: U.S. Fish and Wildlife Service, Department of the Interior.

Appendix C

Atmospheric Processes

C.1 ATMOSPHERIC CHEMISTRY (p. 265)C.2 SOURCE-RECEPTOR RELATIONSHIPS (p. 274)

C.1 ATMOSPHERIC CHEMISTRY*

The atmosphere is a mixture of chemicals—some ofnatural origin, some anthropogenically generated, andsome that are produced by nature as well as by man.These chemicals can react with each other to varyingdegrees under varying conditions. Because the atmos-phere is dynamic, the particular chemical environmentit represents is different for every location, every season,and every meteorological condition.

Both acid deposition and ozone are produced bytransported air pollutants. The dominant precursors ofacid deposition are sulfur dioxide (S02) and nitrogenoxides (NOX). Ozone formation involves NOX and reac-tive hydrocarbons (RHC). Anthropogenic sulfur oxides(S0x) are produced primarily by burning such sulfur-containing fossil fuels as coal and oil. Nitrogen oxidesalso result from the burning of fossil fuel by utility, in-dustrial, and mobile sources. Anthropogenic hydrocar-bon emissions result primarily from petroleum refiningand storage, other industrial process emissions, andmobile sources.

After release into the atmosphere, the particular se-quence of changes a pollutant undergoes depends on thephysical and chemical characteristics of the air mass inwhich it travels, Ultimately, though, because the atmos-phere is 20 percent oxygen, emitted S0x and NOx willoxidize * * and can form acid when combined with water.This can occur while the pollutants are in the air, orfollowing deposition on the Earth. The acids formedmay subsequently be neutralized if appropriate chemicalspecies are available.

Which of many chemical routes is actually followeddepends on: 1) the initial concentrations of all pollutants;and 2) a number of physical factors, such as wind speed,air turbulence, sunlight intensity, temperature, andrainfall frequency.

While scientists know a great deal about individual

● ’1%[$ appertcf[x IS based on (he 0’1’,4 con[ra((or repot-(, ‘ ‘An Asses~mrn(of the Atm{xpherlc Chernlst ry of Oxlcit-s of Sulfur and Nitrogen A{ ld Deposi-tion and Ozone, by B ,J FinlaYson-P,tts a n d J N Pitts, J r , 1 9 8 2

*“Oxidatmn is the procrss of adding ox> gen to a chemical oxidl~ing agentsor ‘ ‘oxidants’ are ( hemt( als that supply the extra nxvgen needed to ( onj ertS02 to sulfate, or NOX to nitrate W’hen sulfate and nitrate cnmblne with water,sulfurlc M Id and nltrlc acid are formed unless neutralized by other chemlc alspresent

chemical reactions and specific physical processes, theycannot precisely characterize the detailed path of a pol-lutant from its origin or ‘ ‘source’ to its removal or“sink. Reactions can occur when pollutants exist asgases, are dissolved in liquids, or adhere to particles.In general, gas-phase reactions predominate in thetransformation of NOX and the production of ozone,while all three phases—gas, liquids, and solids—arepresently believed to play a part in S0x transformationsunder different atmospheric conditions. Nonetheless, thekey atmospheric reactions involved in producing aciddeposition and ozone have some common features andare closely interrelated.

Energy from sunlight triggers chemical reactions thattransform SOX and NOX (which includes NO and NO2)into sulfuric and nitric acid, respectively. Such ‘ ‘photo-chemical’ processes, which also form ozone, require thepresence of RHC. For example, hydroxyl (OH) radi-cals—a very reactive chemical species— initiate the gasphase transformation of S02 to sulfuric acid. Since con-centrations of OH depend, in turn, on concentrationsof ozone, NOX, and RHC, as well as on sunlight in-tensity, the atmospheric chemistry of ozone, NOX, S02,and RHC must be considered together. Altering theconcentrations of any one of these will affect pollutanttransformation and deposition rates.

Deposition of Sulfur and Nitrogen

In the East, approximately two-thirds of the acid de-posited results from sulfur compounds, and one-thirdresults from nitrogen compounds. Over much of theWest, NOX emissions play a relatively greater role inacidification than in the East. To become acids, emittedS 02 and NO, must be oxidized either: 1) in the gasphase, 2) after absorption into water droplets, or 3) afterdry deposition on the ground.

These materials can be deposited on the ground un-changed (as primary gaseous pollutants), or in a trans-formed state (as secondary pollutants). Transformedpollutants can be deposited in wet form (as rain, fog,or snow), or dry form (due to particles containing thesematerials settling out). The amount of time a pollutantremains in the atmosphere, and therefore, how far it

265


is transported, depends significantly on its chemicalform. For example, S02 gas is dry-deposited at a greaterrate than sulfate particles (products of oxidation). If S02

is quickly converted to sulfate, a smaller fraction ofemitted sulfur will be deposited locally, in the absenceof precipitation. The rate of conversion of S02 to sulfatedepends on the chemical composition of the atmosphere.The frequency and intensity of precipitation controls therate of wet sulfur deposition.

Dry deposition is believed to occur at a fairly con-stant rate over time (i. e., a certain percentage of theS02 in the air is dry-deposited each hour), but variessomewhat over different terrain. Wet deposition is epi-sodic, and the amount deposited varies considerablyeven within a rainfall event. For example, a short rainmay deposit heavy doses if pollutants are concentrated—e.g., if they have been forming and accumulating in theair over time. Without sufficient time for pollutant con-centrations to accumulate and be transformed, a secondrain in quick succession may deposit little new acid ma-terial. The product of concentration times rainfall deter-mines the total dose of wet-deposited acidic material.

For this reason, acid fogs (recently identified in theLos Angeles basin) may expose the area to a very highconcentration of acid (a large quantity of acid peramount of water), but significantly smaller amounts ofacid may be deposited than would occur from a rain-fall. On an annual basis, the contribution to total acidloadings depends on the percent of time that fog coversan area. Particularly in high-altitude regions (e. g., theNorthern Appalachian mountains) where cloud coverand fog persist for about 50 percent of the time, precip-itation may account for less acid deposition than fog.The relative effect of high acid concentrations (but lowtotal doses) as compared to high total doses of acid (atlow concentrations) depends on the nature of the recep-tor or ecosystem in question. (See app. B, “AquaticResources, Terrestrial Ecosystems, and Materials.”)

In general, areas close to emission sources receivesignificant proportions of their pollution from steady drydeposition of S02. In locales remote from emissionregions, much of the S02 available for dry depositionhas been depleted or converted to secondary pollutants.In these areas, wet deposition delivers a greater shareof the total pollutant dose than does dry deposition (seefig. C-l). Over most of the nonremote Eastern UnitedStates, the contribution from wet and dry deposition isestimated to be about equal, Air over any particular areawill carry some residual pollution from distant areas,as well as infusions received from more recently passedareas. The continued replenishment and depletion ofpollutants along the path of an air mass makes precisesource-receptor relationships extremely difficult to de-termine.

Atmospheric Chemistry of the Oxides of Sulfur

About 26 million tons of manmade S02 are emittedin the continental United States. About 22 million ofthese tons are emitted in the Eastern 3 l-State region.The oxidation of natural sulfur compounds could con-tribute significantly to atmospheric S02 concentrationsin regions where natural emissions are high (e. g., fromvolcanoes, or some types of marshes) and manmadeemissions are low. However, on a nationwide basis, lessthan 5 to 10 percent of sulfur emissions are attributedto natural sources.

The following discussion of the various fates ofemitted S02 is summarized in figure C-2. One way inwhich sulfate is formed involves S02 gas interacting withOH radicals in a homogeneous gas phase reaction—i.e.,the reactants are all in the gas phase. Because OH ishighly reactive with many atmospheric components,each OH radical has a short lifetime in the atmosphere.Sunlight is necessary for triggering the chain reactionleading to OH production. Consequently, the greatestquantity of SO2 gas is oxidized by OH radicals duringperiods of intense sunlight—i.e, at midday, and in thesummer. The maximum rate at which this reaction con-verts S02 to sulfate is estimated to be about 1 to 4 per-cent per hour. However, field experiments show con-version rates significantly greater (10 to 30 percent perhour) than homogeneous gas-phase reaction rates.Therefore, significant quantities of sulfate must be pro-duced by aqueous (liquid) phase reactions or heteroge-neous reactions involving two phases (i. e., reactions ofgases on either liquid droplets or solid particles).

In aqueous phase reactions, S02 is dissolved in waterdroplets, where oxidants convert the SO2 to sulfate.There is little agreement as to which oxidizing agent (thecandidates include dissolved oxygen, ozone, metals, hy-drogen peroxide, free radicals, and NO,) is most im-portant under particular conditions. The rate of eachoxidizing process may depend on the acidity of the solu-tion; the relative importance of particular oxidizingagents may, therefore, change as acid is formed and thepH* of the water droplet decreases. As acidity increases,S02 is also less easily dissolved, which slows down someaqueous phase reactions significantly. (For example, thepresence of nitrate compounds can increase the acidityof droplets, allowing less S02 to dissolve; the presenceof ammonia in the atmosphere can buffer such increasesin acidity, allowing more S02 to dissolve. ) Currentresearch suggests that the major aqueous phase oxida-tion route for S02 under typical ambient conditions is

“pH is related to acidity. Decreasing pH corresponds to increasing acid, ThepH scale is not linear; a drop of one pH unit reflects a tenfold increase in acidi-ty. Compared to a pH of 7 (neutral), a solution of pH 6 is 10 times more acid,pH 5 is 100 times more acid, and pH 4 is 1,000 times more acid.

App. C—Atmospheric Processes ● 267

Figure C-1 .—The Effects of Time and Distance on Conversion and Deposition of Sulfur PollutionSulfur can be deposited in both its emitted form, sulfur dioxide (lighter shading), and as sulfate, after being chemicallytransformed in the atmosphere (darker shading). Both compounds can be deposited in either dry or wet form. The relativeamount of sulfur deposited in these forms varies with distance from emission sources. Dry deposition predominates in areasclose to emission sources. Wet deposition is responsible for a larger percentage of pollutant load in areas distant fromsource regions.

sulfurdioxide

gas

Dry Wet I Dry Wet I Dry


the reaction with the oxidant hydrogen peroxide, be-cause this reaction occurs quickly and appears to berelatively independent of pH.

A variety of measurements indicate that S02 gas canbe adsorbed onto particles (e. g., carbon soot in plumes)and then oxidized to sulfate. These types of heteroge-neous reaction rates may be particularly significant inurban plumes.

Gas phase, liquid phase, and heterogeneous reactionsmay all be important under differing atmospheric con-ditions, For example, if there is no condensed water andthe concentration of particulate surfaces is low, gas phaseoxidation will predominate during daylight hours. How-ever, if clouds or fog are present, oxidation in theaqueous phase can predominate. In either case, hetero-geneous reactions on surfaces may also be important ifsufficient surfaces associated with particulate are avail-able. Such conditions are most likely near an emissionssource—e.g. , in a powerplant plume.

Overall, current estimates based on empirical obser-vation and model results suggest that homogeneous gas-

phase reactions account for 25 to 50 percent of sulfateformed, and aqueous phase reactions account for theremaining 50 to 75 percent on a regional scale. SOX canbe converted to sulfate quickly in the aqueous phase orin concentrated plumes (e. g., more than 10 percent perhour) or slowly (e. g., less than 1 percent per hour inthe dry winter) in the gas phase. Thus, SOX are avail-able for atmospheric transport for periods of 1 day toabout a week, and will travel varying distances depend-ing on meteorology and precipitation frequency. Theform in which it is deposited depends on the chemistrydescribed above. Ultimately, dry-deposited S02 and sul-fate may also produce acid on the surface of the Earthfollowing oxidation and combination with availablewater (e. g., dew).

Atmospheric Chemistry of Oxides of Nitrogen

Manmade NOX emissions result both from nitrogenbound in fuels and from compounds formed from nitro-gen and oxygen in the air during combustion. Anthro-


Figure C-2.—Schematic Diagram of Possible Fatesof Emitted Sulfur Dioxide Gas

SOURCE: Office of Technology Assessment, modified from Finlayson-Pitts andPitts, OTA contractor report, 1982.

pogenic sources emitted about 21 million tons of NOX

in the continental United States during 1980. About 14million tons were emitted in the Eastern 31-State region.Additionally, natural sources produce several forms ofnitrogen compounds, primarily from soil processes, or-ganic decay, and lightning. Natural sources of reactiveNO, emissions are estimated to produce less than 15percent of total NOX emitted in the Eastern UnitedStates. In North America as a whole, the natural back-ground of NOX may represent 5 to 35 percent of thetotal NOX produced.

Gas phase reactions of NOx have been studied for anumber of years because of their role in forming ozonein photochemical smog. The importance of NOX as asource of acid has only been investigated more recently.

Both ozone and nitric acid formation involve RHCs.The homogeneous gas phase reaction leading to nitricacid (involving the OH radical) occurs about 10 timesas rapidly as the corresponding reaction with S02. Con-sequently, nitric acid formation and deposition shouldoccur at distances closer to the source, constituting more

of a local phenomenon than sulfuric acid deposition. Arecent modeling study of a very polluted area, the LosAngeles basin, suggests that 40 percent of emitted NOX

are transformed into nitric acid over the course of 1 day.Similar rapid conversion occurs in plumes from thenortheast moving over the Atlantic Ocean, a much lesspolluted area.

In addition to nitric acid, other nitrogen-containingspecies are formed in polluted atmospheres—e.g., per-oxyacetylnitrate (PAN), a nitrogen-containing chemicalknown to be toxic to plants. In the winter, when PANis less likely to be decomposed by heat, it may serve asa reservoir for NOX, allowing substantial transportbefore either decomposition or deposition occurs.

Recent experimental evidence indicates that uncata-lyzed aqueous phase reactions of NOX compounds aretoo slow to be important under most atmospheric con-ditions. However, catalyzed aqueous reactions (e.g., dueto the presence of metals or surfaces) may proceed quick-ly and therefore be important.

Ozone

Ozone is regulated by National Ambient Air Quali-ty Standards under the current Clean Air Act, and hasbeen the focus of most oxidant control studies. NOx

react with sunlight and hydrocarbon-produced radicalsto form ozone. Because ozone as well as its precursorscan travel substantial distances, ozone concentrationsdownwind of emissions sources commonly exceed nat-ural background levels.

Naturally produced hydrocarbons, including terpenesfrom pine trees, and methane from termites and wetlandareas, can play a role in forming ozone. Also, additionsof ozone from the upper atmosphere (the stratosphere)will contribute directly to observed levels. Such naturalcontributions can result in ozone concentrations on theorder of 10 to 50 parts per billion (ppb), with commonbackground measurements of about 20 to 30 ppb. Atmidlatitudes in the summer, natural ozone is augmentedby photochemical ozone produced when pollutant pre-cursors react with sunlight. (See app. B, “TerrestrialResources at Risk From Ozone and Acid Deposition,for seasonal ozone levels throughout the United States. )Recent evidence2 suggests that air masses with very lowconcentrations of NOX and RHC (by air quality stand-ards) produce high ozone values in the mountains ofColorado—up to or exceeding the ozone standard. Suchconcentrations may be quite common in the rural Mid-western and Eastern United States; high ozone levelsmay be produced at these sites, especially during thesummer.

‘F. C, Fehsenfeld, M. J, Ballinger, S, C. Liu, et al., ‘‘A Study of Ozonein the Colorado Mountains, ” JournaJ of Amsospheric Chemistry, in press

App. C—Atmospheric Processes . 269

Some of the secondary pollutants (e. g., nitrous acidand formaldehyde) formed along with ozone can them-selves facilitate further ozone production. These second-ary pollutants can remain in a stagnant air mass over-night and react in the presence of sunlight the nextmorning.

IMPLICATIONS FOR CONTROL STRATEGIES

A nonreactive primary pollutant such as carbon mon-oxide (CO) emitted in an urban atmosphere does not,on the time scale of 1 day, undergo significant chemicalreactions during diffusion, dispersion, and transportprocesses. For this pollutant, reducing emissions by 50percent will reduce CO concentrations in ambient airby 50 percent. Thus, in California’s South Coast AirBasin, although the number of vehicle miles traveledhas increased substantially over the last decade, exhaustemission controls put on light-duty vehicles have re-duced ambient CO levels..

However, primary pollutant emissions that can reactrelatively rapidly in the air to form secondary pollutantspresent an entirely different situation. Oxides of nitro-gen and RHCs react in the presence of sunlight to formozone and a host of other secondary pollutants such asformaldehyde, PAN, hydrogen peroxide, nitrous acid,and nitric acid, along with respirable particles. In sucha complex system, the effect of reducing emissions isnot as easy to determine as in the case of CO, i.e., itmay not be ‘‘linear.

The term “linear ‘‘ is used in connection with aciddeposition to indicate that a given percentage reduction(or increase) in emissions would cause the same percent-age change in acid deposition at a specific location.However, a number of factors may cause emissions re-ductions (of SOX, N OX, or RHC) at one location toresult in reductions in acid deposition that are not direct-ly proportional at a particular site downwind. For ex-ample, introducing fresh supplies of NOX and RHC(either individually or together) between controlledsources and a receptor could increase or decrease quan-tities of acid (both nitric acid and sulfuric acid) depositedat that site. In addition, the relative rates at which thevarious chemicals are deposited (e. g., S02 v. sulfate)may also influence the effect of emissions reductions onacid deposition at a particular location.

One of two possible fates occurs to sulfur and nitrogenpollutants: 1) oxidation to sulfuric and nitric acids (orsulfates or nitrates), followed by deposition at the Earth’ssurface; or 2) deposition in their emitted form (i. e., un-changed). In the latter case, chemical oxidation on theEarth’s surface may cause the same net result—i.e.,acidification.

Elevated concentrations of oxidizing chemicals suchas ozone and hydrogen peroxide are found in atmos-

pheres containing anthropogenic emissions. However,it is possible that at certain times and places, the amountof S02 or NOX may exceed the supply of available ox-idants in the atmosphere; when the supply is exhausted,additional acid cannot be made in the air until moreoxidants become available. This would tend to delayacid deposition until the pollutants travel further down-wind. Such conditions of ‘‘saturation’ are thought tobe episodic, and can generally be discounted in regionaldescriptions of transport and deposition.

Until recently, it had been assumed that “natural”water would have an acidity level, or pH, of about 5.6(a pH of 7.0 being neutral, O to 7 being acidic, and 7to 14 basic), due to atmospheric carbon dioxide dissolvedin it. However, even ‘ ‘clean’ atmospheres contain ahost of other chemical constituents as well, which caninteract to produce solutions more or less acidic thana pH of 5.6. For example, it has been shown recentlythat rainwater pHs of less than 5 might be expected in‘ ‘clean air’ environments under certain conditionswhen naturally produced sulfur and chlorine compoundsare present (e. g., in coastal environments).

In determining whether the oxidation of SOX andNOX will actually cause acids to be deposited, the avail-ability of neutralizing species such as ammonia andcalcium (e. g., from windblown dust) must also be con-sidered. Sufficient quantities of neutralizing species willreduce the actual acid formed in the atmosphere. Thus,while two sites may be subjected to identical concentra-tions of anthropogenically produced sulfate and nitrate,quite different levels of acid may be deposited if signifi-cant concentrations of neutralizing species are availableat one location, but not at the other.

The ultimate effect of the deposited compounds, how-ever, is of prime concern. Nonacidic sulfates are prob-ably less damaging to materials than acid sulfates.However, these compounds could eventually act to acid-ify a natural ecosystem. For example, if ammonia com-bines with sulfates, the deposition will not be acidic. Yetammonia, when used by plants and micro-organismsin soils, produces acidity, which can subsequently af-fect soils, lakes, and streams.

Altering Emissions of Primary Pollutants

Characterizing the “chemical soup” of the atmos-phere at any specific location requires integrated infor-mation on the concentrations of all pollutants, the avail-ability of oxidants, the predominance of gas or aqueousphase chemistry, and detailed meteorological informa-tion. The complexities involved in the various chemicaland physical processes allow OTA to make only a verygeneral description of the effect of changing emissionsof various pollutants. The discussion refers to regional-


level response over time, and should not be interpretedas applying to particular episodic events or specific re-ceptor sites.

REDUCING REACTIVE HYDROCARBON EMISSIONS

If NOX concentrations remain at a freed level, reduc-ing RHC emissions subsequently reduces ozone con-centrations, by decreasing production of the free radicalsnecessary for ozone production. The peak ambient con-centrations of ozone are then expected to be lower.

The only mechanism for producing nitric acid be-lieved to be significant in urban areas and powerplantplumes is the oxidation of NO2 by the hydroxyl radical(and possibly by ozone) to produce other oxides of nitro-gen which then form nitric acid. Reducing concentra-tions of RHC would lower the concentrations of the freeradicals as well as of ozone; this should slow down therate at which NOX is oxidized to nitric acid. This slow-ing could in turn cause nitric acid formation and deposi-tion over a larger geographical area, but at lower con-centrations.

Reducing RHC emissions will similarly reduce therate of gas phase oxidation of S02. The rate of liquidphase oxidation by hydrogen peroxide may also decreasebecause its formation rate is proportional to the concen-tration of OH radicals. The effect on other liquid phasetransformations of S02 are difficult to assess but are cur-rently thought to be insignificant.

REDUCING NITROGEN OXIDES EMISSIONS

The question of how decreasing NOX emissions whilekeeping RHC emissions constant would affect ozonelevels is much more controversial than questions asso-ciated with the effects of RHC control. This is becausethe effect of reducing NOX emissions depends on theresulting ratio of hydrocarbons to NOX. Figure C-3shows how ozone levels change with varying levels ofNOX and hydrocarbon emissions. Thus, when the ratioof RHC/NOX is greater than indicated by the diagonalline in figure C-3 (i.e., for the right lower portion ofthe diagram), reducing NOX emissions reduces ozoneconcentrations. However, at lesser ratios (i. e., for theupper left of the diagram), reducing NOX emissionswhile holding RHC levels constant, leads to increasesin ozone concentrations. *

Figure C-3 implies that in the vicinity of emissionscenters like downtown Los Angeles, where the RHC/NOX ratio is less than that of the diagonal line, reduc-ing NoX emissions might increase ozone concentrationsslightly. However, over an entire air basin, includingregions several hundred kilometers downwind, reduc-

● Peak ozone levels decrease because at higher NOX concentrations, a largerportion of the available free radicals react with NOZ to form nitric acid, andbecome unavailable for the chain reactions leading to ozone formation.

ing NoX emissions should decrease ozone concentra-tions overall. Since NO2 is the sole precursor to anthro-pogenic ozone, this must hold true over a large region.

Because NOX concentrations affect the availability ofhydroxyl radicals, decreasing NOX emissions maychange the oxidation rate of S02. The change probablyalso depends on the RHC/NOX ratio, but is poorlyunderstood at present. However, reducing NOX con-centrations, regardless of the ambient hydrocarbon con-centration, decreases the NOX available for nitric acidformation and deposition.

REDUCING REACTIVE HYDROCARBON ANDNITROGEN OXIDES EMISSIONS

SIMULTANEOUSLY

Smog chamber and modeling studies (fig. C-3) showthat simultaneous control of both RHC and NOX—keeping their concentration ratio constant—would re-duce ozone concentrations. As mentioned above, lessnitric acid formation is also expected since the reducedNOX limits how much acid can be formed. In this case,the oxidation rate of S02 is also likely to be reduced.

REDUCING SULFUR DIOXIDE EMISSIONS (ALONE)

Available knowledge of atmospheric chemistry sug-gests that if: 1) there is no shortage of oxidizing agents(i.e., saturated conditions do not prevail); 2) levels ofRHC and NOX remain constant; and 3) depositionprocesses and meteorology remain constant, reducingS 02 emissions will reduce the total amount of acidformed in the atmosphere. Furthermore, given theseconditions, a decrease in S02 emissions should decreasethe atmospheric formation of sulfuric acid by an approx-imately equal proportion.

REDUCING SULFUR DIOXIDE EMISSIONSCONCURRENTLY WITH REACTIVE

HYDROCARBONS AND NITROGEN OXIDES

There are substantial uncertainties in even quali-tatively predicting how simultaneously reducing S02,NOX, and RHC emissions from given sources wouldaffect acid deposition at a distant receptor site. Alter-ing the concentrations of RHC and NOX in an urbanplume that interacts with S02 from a powerplant plumemay well alter the amount of acid deposition at a par-ticular downwind location, but the meteorological andchemical factors involved are so complex that no reliablequantitative estimates can be made at the present time.

For example, changing RHC and NOx emissionswithout changing S02 emissions could affect the deposi-tion of sulfuric acid at a given location by changing theconcentrations of available oxidants needed for convert-ing S02 to sulfate. Further effects could arise if altera-tions in RHC and NOX concentrations affected the pH


Figure C-3.—Typical Ozone Concentrations Formed From RHC-NOX Mixtures

Oxidant/0 3, ppm

0 . 0 8 0 . 2 0 0 . 3 0 0 . 4 0 0 . 5 0 0 . 5 5 0 . 6 0 0 . 6 5

of existing cloud droplets, e.g., through the formationand dissolution of nitric acid in the cloud. For theaqueous phase oxidation of S02, in which the majorprocesses are pH-dependent, changes in cloud aciditylevels could change the rate of sulfuric acid formation.

If the net result of changed RHC and NOX emissionsis faster conversion of S02, sulfuric acid will form andbe deposited closer to sources. If the concentrations ofRHC and NOX are altered such that less oxidizing ma-terial is initially available, sulfuric acid is deposited fur-ther from emission sources. Therefore, alterations in therate of oxidation could change the amount of acid dep-osition to a specific location, but not the total amountof sulfur deposited (e. g., the sum of S02 and sulfates)over the entire downwind area. The sulfur emitted willeventually return to the surface at some point. If NOx

and RHC emissions are decreased such that their ratioremains constant while S02 emissions are decreased,total deposition of both sulfuric and nitric acid willdecrease and total ozone production will decrease.

INCREASE NITROGEN OXIDES, HOLDINGHYDROCARBON AND SULFUR DIOXIDE

EMISSIONS CONSTANTThis scenario is likely to occur without major changes

in current air pollution control regulations. Future in-creases in NOX levels are projected (primarily from util-ities and the industrial sector), while S02 emissions areprojected to remain fairly constant or increase slightlyover the next 20 years (see app. A). Chamber studiesshow that increasing NOX from very low levels, holdingRHC levels constant, causes peak ozone concentrationsto increase. As NOX levels are further increased, ozoneconcentrations reach a maximum and then decreasewith further increases in NOx (see fig. C-3).

The concentrations of other nitrogenous pollutantssuch as nitrous acid also generally increase with in-creased NOX. Increasing NOX emissions while S02

emissions are held constant will augment local acid dep-osition due to nitric acid. Since emitted NOX are ox-idized more readily than S02 in the gas phase, increas-


ing NOX concentrations may expand the geographicalarea over which sulfur deposition occurs.

Source-Receptor Relationships

A major goal of atmospheric science is to predict fora given pollution source, the dose of pollutants at aspecific location downwind, and how changes in thatsource’s emissions would change the pollutant burdenat the receptor site. Source-receptor relationships aredetermined by the location and nature of the primarypollutant emissions (e. g., S02, NOX, RHC) and by as-sociated meteorological, chemical, and physical proc-esses that occur as the pollutants travel from the sourceto the receptor. Current long-range transport modelsthat incorporate sophisticated meteorology (i. e., thoseused in the Canadian-American Work Group effortunder the Memorandum of Intent) attempt to simulatechemical conversions of S02 to sulfate by assuming thatthe complex set of chemical processes will balance outover time and distance to approximate a constant aver-age rate of transformation. This simplifying assumptionmakes regional-scale calculations tractable; crude sourceregions and receptor regions can be identified for sulfurcompounds. Because they are linear models, reducingemissions in source regions results in a proportionalreduction of deposition in receptor regions. These mod-els appear to characterize the current situation for wetdeposition fairly well. They use actual emissions as in-put, and can reproduce observed levels of regional wetsulfate deposited within a factor of 2.

The first attempt to incorporate multiple chemicalreactions involving NOX, S 02, and RHC into a long-range transport model—called the Rohde model—con-tains 19 chemical equations but virtually no meteor-ology. Three of the equations concern sulfuric or nitricacid production. Sixteen of the equations describe thegas phase photochemistry associated with the RHC/NOX systems, ozone, hydroxyl radical, and hydrogenperoxide—all compounds involved in actually formingthe acid. All of the aqueous and heterogeneous phasereactions are combined into one simplified equation.

This model assumes that dry deposition decreases inproportion to emissions. However, it predicts that re-ducing emissions might cause wet deposition to declineless than proportionally -e.g., a response 60 percent asgreat. *

Recently, a Committee of the National Academy ofSciences altered the chemistry in the Rohde model toincorporate new laboratory results. It found that the newassumptions greatly reduced the nonlinearity in the rela-

“See appendix C.2, “Source-Receptor Relationships, ” for further explana-tion. Note that OTA specified the model with conservative assumptions; subse-quent runs using different background concentrations for pollutants over timeshow that wet deposition may respond more directly to emissions reductions.

tionship between ambient S02 concentrations and am-bient sulfate concentrations. Using currently availabledata, the NAS report concludes that, “there is no evi-dence for strong nonlinearity in the relationships be-tween long-term average emissions and deposition.

Very specific source-receptor relationships cannot bedefined unless the behavior of all other pollutants isknown. Given the complexity of the atmospheric chem-istry alone, as well as the need to develop detailed emis-sion inventories (especially for NOX and RHC), and in-herent meteorological variability, it is unlikely that adefinitive model integrating S02, NO2, and RHC willbe developed in the next decade or two. Decisions tocontrol or not to control precursor emissions over thistime period will have to be made without the benefitof such precise information.

Selected References

The following list of references includes recent reviewarticles and several very recent key papers that may notbe included in the review articles cited.

Barrie, L. A., ‘‘The Prediction of Rain Acidity and S02Scavenging in Eastern North America, AtmosphericEnvironment 15:31-41 (1981).

Calvert, J. G. (cd.), Acid Precipitation: SOZ, NO, andN02 Oxidation Mechanisms: Atmospheric Consid-erations (Ann Arbor, Mich.: Ann Arbor Science Pub-lishing, Inc., 1982).

Culvert, J. G., and Stockwell, W. R., “The Mechanismand Rates of the Gas Phase Oxidations of Sulfur Di-oxide and the Nitrogen Oxides in the Atmosphere,Acid Precipitation: S02, NO, and N02 OxidationMechanisms: Atmospheric Considerations (Ann Ar-bor, Mich.: Ann Arbor Science Publishing, Inc.,1982).

Chamberlain, J., Foley, H., Hammer, D., MacDonald,G., Rothaus, O., and Ruderman, M., “The Physicsand Chemist~ of Acid Precipitation, Technical Re-port No. JSR-81-25, prepared for the U.S. Depart-ment of Energy, September 1981.

Chameides, W., and Davis, D. D., “The Free Radic~Chemistry of Cloud Droplets and Its Impact Uponthe Composition of Rain, J. Geophys. ~es. 486,1982.

Charlson, R. J., and Rodhe, H., “Factors Controllingthe Acidity of Natural Rainwater, Nature 295, 683(1982).

Eldred, R. A., Ashbaugh, L, L., Cahill, R. A., Floc-chini, R. G., and Pitchford, M. L., “Sulfate Levels

‘Acid Deposition, Atmospheric Processes in Eastern North America, Com-mittee on Atmospheric Transport and Chemical Transformation in AcidPrecipitation, National Research Council (Washin@on, D. C.: NationalAcademy Press, 1983).


in the Southwest During the 1980 Copper SmelterS t r i ke , paper submitted to Science.

Electric Power Research Institute, Aircraft Measure-ments of Pollutants and Meteorological ParametersDuring the Sulfate Regional Experiment (SURE)Program, EPRI Report EA-1909 (Palo Alto, Calif.:Electric Power Research Institute, 1981).

Finlayson-Pitts, B. J., and Pitts, J. N., Jr., “TheChemical Basis of Air Quality: Kinetics and Mech-anisms of Photochemical Air Pollution and Applica-tion to Control Strategies, Advan. Environ. Sci.Technol. 7, 975 (1977).

Graedel, T. E., and Weschler, C. J., “Chemistry With-in Aqueous Atmospheric Aerosols and Raindrops,Rev. Geophys. Space Phys. 19, 505 (1981).

Hegg, D. A., and Hobbs, P. V., “Oxidation of SulfurDioxide in Aqueous Systems With Particular Refer-ence to the Atmosphere, “ Atmos. Environ. 12, 241(1978).

Hoffman, M. R., and Jacob, D. J., “Kinetics andMechanisms of the Catalytic Oxidation of DissolvedSulfur Dioxide in Aqueous Solution: An Applicationto Nighttime Fog Water Chemistry, Acid Precipi-tation: S02, NO, and NOP Oxidation Mechanisms:Atmospheric Considerations (Ann Arbor, Mich.:Ann Arbor Science Publishers Inc., 1982).

Larson, T. B., “Secondary Aerosol: Production Mech-anisms of Sulfate Compounds in the Atmosphere,Ann. N, Y. Academy of Sciences 338, 12 (1980).

Martin, L. R., ‘ ‘Kinetic Studies of Sulfite Oxidationin Aqueous Solutions, “ Acid Precipitation: S02, NO,NOP Oxidation Mechanisms: Atmospheric Consid-erations (Ann Arbor, Mich. : Ann Arbor SciencePublishers, Inc., 1982).

National Research Council, Acid Deposition, Atmos-pheric Processes in Eastern North America, Commit-tee on Atmospheric Transport and Chemical Trans-formation in Acid Precipitation (Washington, D. C.:National Academy Press, 1983).

Oppenheimer, M., ‘ ‘The Relationship of Sulfur Emis-sions to Sulfate in Precipitation, Atmos. Environ.,in press.

Platt, U., and Perner, D., “Detection of NOt in thePolluted Troposphere by Differential Optical Absorp-t i o n , Geophys. Res. Lett. 1, 89 (1980).

Platt, U., Perner, D., and Kessler, C., “The Impor-tance of N03 for the Atmospheric NOX Cycle FromExperimental Observations, paper presented at the2d Symposium on the Composition of the NonurbanTroposphere, Williamsburg, Va., May 25-28, 1982.

Platt, U. F., Pitts, J. N., Jr., Biermann, H. W., andWirier, A. M., ‘ ‘Spectroscopic Measurements of theNitrate Radicals at Four Rural Sites in Southern Cal-ifornia: Implications for Acid Precipitation,manuscript in preparation.

Rahn, K. A., “Elemental Traces and Sources of Atmos-pheric Acidity for the Northeast—A Statement ofNew Evidence, ” Statement of Nov. 3, 1981; “Trac-ing Sources of Acid Rain Causes Big Stir, note in“Research News” section of Science, February 1982.

Rodhe, H., Crutzen, P., and Vanderpol, A., “Forma-tion of Sulfuric and Nitric Acid in the AtmosphereDuring Long Range Transport, ” 7’eilus 33, 132,1981.

Russell, A. G., McRae, G. J., and Cass, G. R., “AcidDeposition of Photochemical Oxidation Products—A Study Using a Lagrangian Trajectory Model,paper presented at the 13th International TechnicalMeeting on Air Pollution Modeling, Toulon, France,Sept. 14-18, 1982.

Spicer, C. W., ‘‘The Distribution of Oxidized Nitrogenin Urban Air, ” Scie. Total Environ. 24, 183 (1982).

Tuazon, E. C., Wirier, A. M., and Pitts, J. N., Jr.,Environ. Sci. Technol. 15, 1232, 1981.

U.S. Environmental Protection Agency, “The AcidicDeposition Phenomenon: Transformation Proc-esses, chapter A-5 in the Critical Assessment Docu-ment entitled ‘‘The Acidic Deposition Phenomenonand Its Effects, draft copy, May 10, 1982.

Waldman, J. M., Murger, J. W., Jacob, D. J., Flagan,R. C., Morgan, J. J., and Hoffmann, M. R.,“Chemical Composition of Acid Fog, ” Science, inpress.


C.2 SOURCE-RECEPTOR RELATIONSHIPS

Introduction

Broad regions of North America receive acidic deposi-tion both in wet form—acid rain— and as dry deposi-tion of acidic substances. Because acidifying substancesreach the Earth from the atmosphere both through re-moval by rainfall and as directly deposited gases andparticles from the air, the term acid rain is misleading.The acidity of rainfall per se is generally considered lesssignificant than the quantity of ‘acid-producing’ sub-stances added to the environment—onto soils, vegeta-tion, and materials, and, after passing through water-sheds, into lakes and streams. The term acid-producingsubstances as used in this report refers to sulfur oxides(SOX) and nitrogen oxides (NOX) and other substancesthat have the potential for producing acidity, althoughthey may not be deposited in an acid form. For exam-ple, sulfate can be deposited in a neutral form—ammo-nium sulfate—but end up as sulfuric acid by the timeit reaches a lake or stream if the ammonium is used byplants in the watershed.

The chain of physical and biological processes fromemissions of pollutants to eventual deposition of acid-producing substances in the environment is complex andnot fully understood. However, several lines of evidencecan be combined to express the likely relationship be-tween emissions and deposition.

Acid deposition results from both local and distantsources of SOX and NOX, Current scientific understand-ing suggests that reducing sulfur dioxide (S02) emis-sions throughout the Eastern 3 l-State region wouldreduce the deposition of acid-producing substances; butthat this will occur in the areas sensitive to acid deposi-tion cannot be stated with certainty. For the EasternUnited States, no other control strategy offers greaterpotential for reducing acid deposition than reducing S02

emissions. While curbing other pollutant emissionscould be considered simultaneously, and might ultimate-ly be necessary to achieve a desired level of depositionreduction, most scientists would focus initial attemptsto control acid deposition on S02.

By considering preliminary information drawn fromseveral alternative approaches, one can piece togethera plausible relationship between pollutant emissions anddeposition of acid-producing substances. This appen-dix addresses four key issues. The discussion begins withregional-scale deposition of acidifying substances, andthen identifies the major constituents of deposition andthe relative magnitude of current sources. Model-basedestimates of how pollutant emissions from parts of theEastern United States affect deposition in other areas

are then discussed. Two complementary modeling ap-proaches are used to estimate the magnitude of poten-tial reductions in acid-producing substances reachingthe environment due to reductions in S02 emissions.Finally, the analysis addresses the question of whetherthese potential reductions in acid-producing substancesmight be enough to meet ‘‘target’ deposition rates toprotect sensitive resources.

Current Deposition ofAcid-Producing Substances

The best information on patterns of acidic deposi-tion—both its chemical composition and spatial distribu-tion over affected parts of North America—comes frommonitoring networks collecting rainfall samples. Thoughwet deposition may account for only about half the de-posited SOX and NOX, ” dry-deposited gaseous and par-ticulate pollutants are not monitored extensively enoughto determine their precise distribution. This discussionfocuses primarily on acid-producing substances depos-ited through precipitation.

The balance of chemical species originating from suchnatural sources as seaspray, windblown soil, and car-bon dioxide in the air, and such manmade sources asSOX and NOX pollutants, determine the acidity of rain-fall. Rainfall acidity can be decreased either by remov-ing acid-producing substances, or by adding acid-neutralizing substances. The major acid-producingsubstances in rainfall in the Eastern United States areS OX and NOX from both natural and manmadesources. However, the presence of these substances inrainfall does not necessarily indicate acidity since theycan be counterbalanced by such airborne acid-neutral-izing substances as calcium and magnesium from soiland ammonium from natural sources and fertilizers.

Patterns of acidity, sulfate, and nitrate deposition inrainfall over Eastern North America are mapped infigures C-4 through C-6. Figure C-4 presents the deposi-tion of hydrogen ions—the substance actually measuredto determine acidity. More than 40 milliequivalents persquare meter per year (meq/m2/yr) of hydrogen ions are

● Most long-range transport air pollution models estimate that dry deposi-tion is about equal to wet deposition when averaged over the Eastern UnitedStates. The ratio of dry to wet deposition varies with distance away from sourcesof pollution, with ratios on the order of 8 to 12 in areas with high S02 concen-trations, to about 0.2 to 0.4 in the Adirondack Mountains (D. Fowler, “Removalof Sulphur and Nitrogen Compounds From the Atmosphere, Ecological Im-pact of Acid Precipitation, SNSF project, October 1980. A.H. Johannes, etal., “Relationships Between Wet Deposition, Dry Deposition and Through-fall Chemistry, ” Air Pollution Control Association Annual Meeting, NewOrleans, June 1982.


milliequivalents per square meter)


per square meter)

SOURCE: Impact Assessment, Work Group 1, United States-Canada Memorandum of Intent on Transboundary Air Pollution, final report, January 1983.


Figure C6.—Nitrate in Precipitation During 1980(weighted by precipitation-milliequivalents per square meter)

●

SOURCE Impact Assessment, Work Group 1, United States-Canada Memorandum of Intent on Transboundary Air Pollution, final report, January 1983


deposited over broad regions of the Eastern UnitedStates, in contrast to deposition rates under 10meq/m2/yr throughout much of the West. The highestdeposition rates exceed 80 meq/m2/yr, and are centeredaround eastern Ohio, western Pennsylvania, and north-ern West Virginia.

Of the major acid-producing substances in rainfall,only two originate in substantial amounts frommanmade sources in the Eastern United States: sulfatesand nitrates. The patterns of deposited acidity anddeposited sulfate (fig. C-5), are quite similar. A largerpart of the Eastern United States receives deposition inexcess of 40 meq/m2/yr. The highest deposition ratesagain exceed 80 meq/m2/yr, centered in about the sameregion. Nitrate deposition patterns are similar (figs. C-5and C-6), but deposition rates are about one-half thosefor sulfur. More than 20 meq/m2/yr of nitrates aredeposited over broad regions of the Eastern UnitedStates, with peak deposition exceeding 40 meq/m2/yr.About two-thirds of the total sulfate and nitratedeposited in the Eastern United States is sulfate.

By comparing figures C-4 through C-6, one can seethat the deposition of acid-producing substances (sulfateand nitrate) exceeds the deposition of acidity by about25 to 50 percent; this portion of the sulfate and nitrateis neutralized by such other constituents as calcium andammonium.

Reducing sulfate deposition might be the most likelyway to begin reducing the deposition of acidity, giventhat about twice as much sulfate as nitrate is presentin rainfall. Similar patterns are assumed to occur fordry deposition of acid-producing substances, but farfewer observations are available to substantiate this.

The most significant indicator for assessing alterationsin lake- and stream-water quality is the acidity of waterafter it flows through a surrounding watershed—i.e.,the total amount of acid-producing substances that even-tually reach and travel through aquatic environments.Figure C-7 illustrates the relationship between the quan-tity of acid-producing substances in rainfall and thequantity of acid-producing substances in water flowingout of a watershed. Figure C-7A shows that the amountof sulfate leaving a watershed is about equal to, and inmany cases greater than, the amount entering a water-shed in rainfall, when averaged over a period of one orseveral years. That more sulfur leaves a watershed thanenters from rainfall is probably due to the amounts thatenter as dry-deposited gases and particles.

For nitrogen-containing substances such as nitrateand ammonium (as shown in fig, C-7 B), the picture isdifferent. Only about one-third of the nitrogen enter-ing a watershed from rainfall leaves the watershed. Ifthe nitrogen input from dry deposition is included, theratio of nitrogen leaving to nitrogen entering a water-shed becomes even lower. As discussed in the forest

Figure C-7.—Sulfur and Nitrogen: Quantities inPrecipitation Versus Quantities in

Outflow From Watersheds

A: Annual input of SO~- – S by precipitation versus the leachinglosses from forest watersheds and Iysimeters with forest soils. Solidline is the regression line, dotted line is the 1:1 line.

resources section, these results might be expected—whileboth nitrogen and sulfur are essential nutrients for forestgrowth, most eastern forests require far greater inputsof nitrogen than sulfur.

In summary, about twice as much sulfate is general-ly present in rainfall as nitrate. When considering the


acid-producing substances that travel through the en-vironment (and effects such as altered lake- and stream-water quality), sulfate may predominate even more.This can vary from region to region, and certainly variesfor short periods. For example, the nitrate componentof spring snowmelt can be as great as or even greaterthan sulfate levels in some watersheds. However, overbroad regions on an annual time scale, sulfates com-prise a much larger share of acid-producing substancesthan nitrates.

Manmade and Natural SourceContributions to Acidic Deposition

Relatively low background levels of acidic depositionare thought to originate from natural sources (andpossibly global-scale transported air pollutants), whenaveraged over large regions (e. g., the Eastern UnitedStates or the North American Continent). This “naturalbackground” deposition of wet sulfur in North America(excluding Mexico) has been estimated to be about 4to 10 meq/m2.4 This is about 20 to 40 percent of theaverage sulfur deposition from precipitation over all ofNorth America. Natural sources contribute relativelysmaller proportions in areas of highest deposition. Aver-aged over Eastern North America (east of the Mississip-pi and south of James Bay in Canada), natural back-ground sources might contribute about 12 to 25 percentof the total. Another group has estimated natural sourcesof sulfur to be about 5 to 10 percent of manmade sourcesin this same region. 5 Over parts of the Eastern UnitedStates, where wet sulfur deposition exceeds 50 meq/m2

and is as high as 80 meq/m2 in some areas, the naturalbackground contributes even less.

This natural background comes from several differentsources: Husar estimates that 6 percent of the wet sulfurdeposition in North America originates from seaspray.The Electric Power Research Institute (EPRI) hasestimated that about 5 percent of SO2 emissions origi-nate from natural, biological sources.6 In addition,geologic sources such as volcanoes are thought to con-tribute to natural background.

When averaged over the North American Continent,the acid-producing potential of manmade SO2 emissionsfar exceeds total wet sulfur deposition. The over 30million tons of S02 emitted by manmade sources inNorth America is 2.5 times total wet sulfur depositionand 6 to 10 times the natural background. The portion

*R. B. Husar and J. M. Holloway, “Sulfur and Nitrogen Over NorthA m e r i c a , presented at 1982 Stockholm Conference on Acidification of theEnvironment

5Atmospheric Sciences and Anafysls, Work Group 2, United States-CanadaMemorandum of Intent on Transboundary Air Pollution, Final Report,November 1982

cElectrlc Power Research Institute, “ Biogenic Sulfur Emissions m the SURERegion’ EA-1516, 1980

of manmade sulfur that is not deposited in rainfall iseither deposited dry or exported off the continent.

Natural background is estimated to contribute similarproportions of total wet nitrate deposition—about 20 to40 percent when averaged over the North AmericanContinent, and about 10 to 25 percent when averagedover Eastern North America.

The Relationship Between CurrentEmissions and Deposition

One of the major controversies in the acid rain debateis the effect that pollutant emissions from any source(or group of sources) will have on ambient air qualityand pollutant deposition at some other location. Therelationship between emissions and deposition is deter-mined by a complex chain of chemical and physicalprocesses that occur as primary pollutants (e. g., S02)are emitted, transformed into secondary pollutants (e. g.,sulfates), transported, and finally deposited.

Computer models, called transport models, are usedto mathematically simulate the transformation,transport, and deposition processes. Models describinglong-range transport of S0x have been available forseveral years; preliminary models of NOX transport arejust now being developed. Transport models are the onlypractical procedure available to estimate the relation-ship between areas of origin and areas of deposition forlong-range transport pollutants, unless newly developedtracer techniques prove reliable. Large-scale regionaltransport cannot now be measured directly for the largenumber of sources of emissions and deposition regionsof interest, and under the variety of meteorological con-ditions needed to perform the analysis.

The major long-range transport (LRT) models de-scribing SOX transport incorporate six atmosphericprocesses:

1. release of emissions,2. horizontal transport and dispersion,3. vertical mixing of pollutants in the atmosphere,4. chemical transformation,5. dry deposition, and6. wet deposition.

The models themselves are composed of submodelswhich simulate chemical and physical processes withinthese broader categories. The main data requirementsof LRT models are: emissions inventories of pollutants,meteorological data, ground cover data, and a host ofvalues (parameters) representing chemical reaction ratesand other physical processes.

Eight LRT models were evaluated under the U. S.-Canada Memorandum of Intent (MOI) on Trans-boundary Air Pollution;

7 results indicate that the models

7Atmospheric Sciences and Analysis, op cit,

99-413 0 - 84 - 1 9 s QL . 3

—

280 . Acid Rain and Transported Air Pollutants: lmplications for Public Policy

appear to reproduce large-scale patterns of observed wetsulfur deposition. However, the size and quality of thedata base precludes a complete evaluation of LRT mod-els at this time. *

This section presents modeling results to provide aplausible description of the current relationship betweensources and deposition of SOX in the Eastern UnitedStates. This is only one of the acid-producing substancescurrently deposited; however, as discussed earlier, sul-fate is currently the major acid-producing substance inprecipitation.

The model used in this analysis is the AdvancedStatistical Trajectory Regional Air Pollution Model(ASTRAP) developed by Argonne National Laboratoryunder DOE and EPA funding. The ASTRAP modelincludes several components of the source-receptorrelationship not included in the other models. * *

OTA has used another model that incorporates morerealistic atmospheric chemistry and considers the effectsof co-pollutants such as NOX and hydrocarbons (but atthe expense of sophisticated meteorology), to assess howthe simplifying chemical assumptions used in ASTRAPmight affect its resulting projections. This comparisonindicates that the ASTRAP model might adequatelyrepresent dry deposition of sulfur, but that variationsin ambient concentrations of other pollutants might sig-nificantly affect wet sulfur deposition. (These results arediscussed in the preceding subsection, “AtmosphericChemistry.”)

Because of its sophisticated treatment of the regionalpatterns of emissions and meteorology, the ASTRAPmodel can be used to investigate the current relation-ship between regions of S02 emissions and regions ofsulfur deposition. The model is best used in a relativesense—e.g., estimating the proportion of deposition oneregion contributes to another—rather than for project-ingthethenot

the magnitude of deposition quantitatively: Againfollowing discussion of sulfur deposition describesgeneral pattern of current relationships, and mustbe interpreted as making quantitative predictions.

“Even if the models were ‘ ‘perfect, ” one would expect the model simula-tions to deviate from the obsemations since the latter are influenced by boththe factors treated in the model and the factors that are not treated (e. g., small-scafe precipitation variations). In addition, part of the difference between modelsimulations and observations is due to the inherent variability of the real world.The model is of necessit y designed to simulate an average of the observationswhife the monitoring data base at this time is insufficient to calculate a represent-ative average (i. e., the average over a number of years with similar emissions,meteorological conditions, etc.),

● “The ASTRAP model includes: the abifity to account for seasonal differences(the ASTRAP model simulates January and July average conditions); releaseheight of emissions; the use of detailed meteorological data; consideration ofvertical atmospheric processes in addition to horizontal movement; wet deposi-tion rates that vary with rainfall intensity; and dry deposition rates that varytemporally and spatially. The other models evafuated include some of thesecomponents, but ASTRAP is the only model that includes all of them.

Acid deposition has often been characterized as ‘ ‘acidin Adirondack lakes from powerplants in Ohio. TheASTRAP model can be used to show that such state-ments are overly simplistic: pollutants do travel fromone region to another, but in all directions, not just westto east. In addition, while pollutants can travel longdistances, emissions within a region contribute a largeshare to total deposition in that region.

To illustrate these points, figure C-8 divides easternNorth America into four regions. The intersection ofthe regions has been chosen to correspond to the areaof peak wet sulfur deposition in 1980. Figure C-8 alsodisplays the percentage of S02 emitted in each region,and the percentage of total sulfur deposited (as simulatedby ASTRAP) in each of the regions. Sulfur dioxideemissions are roughly comparable in the northeasternregion (I), southeastern region (II), and southwesternregion (III). Emissions in the northwestern region (IV)are over twice the amount of any of the other regions.Deposition is lowest in the southern regions (II and III)and highest in the northern regions (I and IV).

Figures C-9 through C-12 show model-based esti-mates of: 1 ) the percentage of each region’s depositionoriginating from within its borders, and from each ofthe other regions; and 2) for deposition originating out-side a region, the percentage of deposition traveling lessthan 500 km, 500 to 1,000 km, 1,000 to 1,500 km, andgreater than 1,500 km.

For example, figure C-9 illustrates these relationshipsin region I (the northeastern region). The pie chart inthe upper right projects that approximately 80 percentof the deposition comes from emissions in two regions—from within its own borders and from the northwesternregion in about equal amounts. The bar graphs placedin regions II, III, and IV illustrate each region con-tribution to deposition in the northeastern region, ac-cording to its distance from the sources of emissions.For example, the bar graph in the lower right showsmodel estimates that 40 percent of the deposition com-ing from the southeastern region travels less than 500km to its eventual area of deposition in the northeast;another 40 percent travels between 500 to 1,000 km,and the remainder travels over 1,000 km.

Figures C-9 through C-12 demonstrate the followinggeneral observations:

1.

2.

3.

4.

All regions contribute to deposition in all otherregions.At the spatial scale used in this analysis, eachregion generates as much or more of its own dep-osition as any other single region contributes to it.Substantial quantities of deposition originate fromsources over 500 km away.Pollutants are transported further from west to eastand south to north than from east to west or northto south.

App. C—Atmospheric Processes 281

Figure C-8.—1979 Sulfur Dioxide Emissions and Estimated Sulfur Deposition—Percent Contributedand Received in Four Subregions Covering the Eastern Half of the United States

SOURCE” J Shannon, personal communication, Argonne National Laboratory and E. H. Pechan & Associates, Inc., 1982


Figure C-10. —DepositionPERCENT DEPOSITION FROM REGION IV TO II BY DISTANCE

PERCENT DEPOSITION FROM REGION Ill TO II BY DISTANCE

in Region II

PERCENT DEPOSITION FROM REGION I TO II BY DISTANCE

SOURCE: J. Shannon, personal communication, Argonne National Laboratory and E, H. Pechan & Associates, Inc., 1982


a

w


1


The Effectiveness of Emissions Reductionsfor Achieving Deposition Reductions

Assumptions concerning the physical and chemicalprocesses involved in transforming S02 to sulfate areinherent in the use of regional-scale models such asASTRAP. Linear regional-scale models assume thatsulfate production is proportional to the concentrationof S02. The source-receptor relationships described bythese models can simulate expected changes in deposi-tion only to the extent that deposition would actuallychange in linear proportion to changes in emissions.

While the preceding source-receptor relationshipsmay provide reasonable estimates of inter- and intra-region transport, they may not be reliable for develop-ing control strategies unless chemical transformation anddeposition processes can be shown to behave in a linearmanner. This section first discusses linear model pro-jections of the effects of different emissions scenarios andthen considers how the addition of more realistic atmos-pheric chemistry might alter the results.

OTA used the ASTRAP model to simulate atmos-pheric concentrations and surface deposition of sulfurpollutants for three alternative levels of S02 emissions. *These include: current emissions levels in the UnitedStates and Canada; a representative 8-million-ton-per-year emissions reduction; and a representative IO-mil-lion-ton-per-year emissions reduction. * *

The model was used to simulate deposition levels dur-ing January and July, to investigate the effects of bothwinter and summer conditions. Figure C-13 displaysmodel projections of how extensively both wet and drysulfur deposition would be reduced by a representative10-million-ton reduction in S02 emissions. The reduc-tions shown apply only to emissions originating in theUnited States (i.e., deposition from emissions in Canadaare not considered). Similar projections for an 8-million-ton reduction are shown in figure C-14. The pattern ofdeposition reductions is similar for both scenarios.Deposition is reduced by the greatest percentage in theMidwest—the region with both the highest current emis-sions and the greatest reduction requirements underboth scenarios. Proportional reductions in depositiondecline with distance away from this region. Becausethe ASTRAP model assumes a linear relationship be-tween emissions and deposition, both scenarios show

● Personal communication, J. Shannon, Argonne National Laboratory,December 1981.

● ● Senate bills S. 1706 and S. 1709 (97th Congress) were two of the earliestlegislative proposah to control acid deposition. S. 1706 (introduced by SenatorMitchell of Maine) and S. 1709 (introduced by Senator Moynihan of New York)were both referred to the Senate Committee on Environment and Public WorksOctober 1981. The State-level reductions specified by these bills were used asthe basis for the 10- and 8-million-ton reduction scenarios, respectively. Thesescenarios assume that reductions in emissions from each point source withina State are proportional to the reduction assigned that State in the OTA analysisof these bills.

that total deposition is reduced almost in proportion toreductions in total emissions when averaged over theentire Eastern United States.

Assuming a linear relationship—i.e., that a specifiedpercentage reduction in emissions will lead to the samepercentage reduction in deposition—is a simplificationadopted for computational advantages. No one wouldargue that this simplified relationship realisticallyrepresents the complex transformations occurring in theatmosphere. Over 100 chemical reactions may poten-tially play a role in transforming S02 to sulfate. Unfor-tunately, the chemical transformation process cannot becompletely evaluated at present, since importantelements of many of the equations are not known. Theimportance of understanding the full ensemble ofchemical reactions cannot currently be evaluated. Amore pertinent question is: how accurately can a linearrelationship approximate these reactions over the largetime and space scales involved in regionwide emissionsand deposition?

Clearly the total amount of sulfur emitted to the at-mosphere is eventually deposited; thus, ultimately,reductions in deposition will approximate emissionsreductions. (Deposition from natural sulfur sources,though small, would remain. ) The crucial question iswhere sulfur deposition would be reduced—i.e., inabout the same regions as predicted by the linear mod-els, closer to emissions sources, or further away?

To examine the linearity of the chemical transforma-tion system, a second model, capable of simulating theinteractions of several pollutants that may affect sulfurdeposition, was run for OTA.8

This model, developed by Rodhe, et al. (1981), allowsa reasonable qualitative evaluation of pollutant interac-tions while remaining computationally tractable. Themodel’s limited description of atmospheric mechanisms(e. g., mixing of pollutants with surrounding air) couldaffect its quantitative results. In addition, it does notincorporate the meteorology necessary to describe com-plex patterns of deposition. Nonetheless, it representsa useful step forward from linear modeling, by simu-lating chemical transformations that occur in the at-mosphere, through a series of 19 chemical equations.The Rodhe model can provide a qualitative picture ofhow changes in other primary pollutant emissions—principally reactive hydrocarbons (RHC) and nitrogenoxides (NOX)—might affect downwind sulfur depo-sition.

Dry sulfur deposition depends highly on the concen-tration of S02 in the atmosphere. Changing the con-centrations of RHC and NOX might alter the rate atwhich S02 is converted to sulfate, and change the reser-

6Perry J Samson, ‘‘On the Linearity of Sulfur Dioxide to Sulfate Conver-sion in Regional-Scale Models, OTA contractor report, June 1982.



Figure C-14.– Estimated Deposition Following an 8-Million-Ton-per-Year Reduction in Sulfur Dioxide Emissions


voir of S02 available for dry deposition. However, themodel simulations indicate that dry sulfur deposition isfairly insensitive to the NOX and RHC mixture in theatmosphere. Figure C-15 illustrates this by showing howmuch dry sulfur deposition changes per unit change ofprimary pollutant concentrations as a function of timedownwind of a source region, as predicted by the Rodhemodel. It shows that, of the three pollutants considered,S02 has by far the greatest effect on dry sulfur deposi-tion. In addition, the figure shows that, for pollutanttravel times of less than 2 days, a given percentagereduction in emissions appears to reduce dry sulfur dep-osition comparably. Thus, since most dry deposition oc-curs within this time period, omitting co-pollutants andassuming a linear relationship in regional-scale modelssuch as A STRAP may be a reasonable assumption forpredicting changes in the dry sulfur component of dep-osition.

Wet sulfur deposition may respond to changes inpollutant emissions differently than dry deposition. Asshown in figure C- 16, changing the initial amounts ofS02 by 50 percent might result in roughly a 30-percentchange in wet sulfur deposition. ● One must keep inmind that these results are highly dependent on themodel’s approximation of chemical transformations inclouds. Because such processes cannot yet be simulatedin detail, the accuracy of this result cannot be evaluatedat this time.

However, like dry deposition, wet sulfur depositionis affected more by changes in S02 concentration thanby changes in other pollutant concentrations. Nonethe-less, it should be noted that wet sulfur deposition isrelatively sensitive to changes in RHC. Reducing RHCemissions could decrease wet sulfur deposition, althoughthe effect would not be as pronounced as equivalent re-ductions in S02. The sensitivity of wet sulfur deposi-tion to changes in NOX concentrations is less pro-nounced, but in the opposite direction—i.e., reducingN OX emissions might lead to a small increase in wetsulfur deposition. However, this increase might be off-set by decreased dry sulfur deposition and reductionsin nitrate deposition.

The Rodhe model is not intended to estimate pollu-tant deposition quantitatively. It was employed toevaluate pollutant interactions qualitatively and assesshow they might affect dry and wet sulfur deposition.The results suggest that wet sulfur deposition is relativelysensitive to the mix of RHC and NOX, while dry sulfurdeposition is not.

‘This estimate is for 1 ) relatively high initial concentrations of pollutants,such as those found in the Ohio River basin during pollution episodes, and2) an ‘‘average’ rainfall event ( 1 hour at 1 mm/hr) 24 hours downwind of thesource.

An analysis performed by a committee of the NationalResearch Council/National Academy of Sciences9

(NAS) came to a similar conclusion. This committeeslightly modified the Rodhe model used by OTA to re-flect some recent laboratory results and to change someassumptions about mixing of chemicals in the atmos-phere. Their results suggest that the role of NOX andRHC are somewhat less important than indicated bythe “worst-case” assumptions used by OTA.

Both the OTA and NAS analyses suggest that ifreducing total sulfur deposition is a desired goal, reduc-ing S02 emissions would likely be an effective strategy.The NAS report concludes,

If we assume that all other factors, including meteor-ology, remain unchanged, the annual average concen-tration of sulfate in precipitation at a given site shouldbe reduced in proportion to a reduction in S02 and sulfatetransported to that site from a source or region of sources.If ambient concentrations of NOX, nonmethane hydrocar-bons, and basic substances (such as ammonia and calciumcarbonate) remain unchanged, a reduction in sulfate dep-osition will result in at least as great a reduction in thedeposition of hydrogen ion.

“Target” Deposition RatesTo Protect Sensitive Resources

The previous discussion considered only the ex-tent to which decreasing S02 emissions by 8 millionand 10 million tons per year in the Eastern 31 -Stateregion would reduce total sulfur deposition. No at-tempt was made to relate these estimates to prevent-ing potential damage to sensitive resources. At leastthree separate groups have estimated deposition‘‘targets’ ‘—i.e., levels of deposition below whichsensitive lakes and streams are not expected to fur-ther acidify. * *

The Impact Assessment Working Group estab-lished under the U.S. -Canada Memorandum of In-tent on Transboundary Air Pollution suggested thefirst of these targets.

10 Both the U.S. and Canadianmembers agreed that for North America:

There have been no reported chemical or biological ef-fects for regions currently receiving loadings of sulphatein precipitation at rates less than about 20 kg/ha-yr[kilograms per hectare per year]. Evidence of chemicalchange exists for some waters in regions currently

estimated or measured to be receiving about 20-30 kg/ha-yr sulphate in precipitation . . . . Long-term chemical

‘NRC INAS, Acid DepositIon. Atmospheric Processes in Eastern NorthAmerica, National Academy Press, Washington, DC,, 1983

● *OTA estimates of the effects of changes m deposluon on acid-altered aquatl{resources are presented In app B Rather than presenting specltic depositiontargets to prevent aclddication of sensltwe resources, the effects of three scenariosof changes in wet sulfur deposition are discussed

I o~mpact Assessment, work croup 1, U S - C a n a d a Mmmandm of in-

tent on Transboundary Am Pollution, Finaf Report, January 1983


Figure C-15.—Changes in Wet Sulfur

1.0

0.8

0.6

0.4

0.2

0.0

–0.2

–0.4

–0.6

–0.8

– 1.0


Figure C-16. —Changes in Dry Sulfur Deposition


and/or biological effects and short-term chemical effectshave been observed in some low alkalinity surface watersexperiencing loadings greater than about 30 kg/ha-yr.

Based on these observations, the Canadian members ofthe group proposed that

. . . deposition of sulfate in precipitation be reduced toless than 20 kg/ha-yr [about 18 lbs/acre-yr] in order toprotect all but the most sensitive aquatic ecosystems inCanada.

The U.S. members concluded that based on the cur-rent status of scientific understanding about the mech-anisms that lead to surface water alteration, ‘‘it is notnow possible to derive quantitative loading/effectsrelationships. *‘

A recently published National Research Council/Na-tional Academy of Sciences (NAS) report uses the acidi-ty of precipitation, rather than the concentration ofsulfates, to specify a level that would protect sensitivefreshwater ecosystems.11 NAS states:

It is desirable to have precipitation with pH values nolower than 4.6 to 4.7 throughout such areas, the valueat which rates of degradation are detectable by currentsurvey methods. In the most seriously affected areas(average precipitation pH of 4.1 to 4.2), this would meana reduction of 50 percent in deposited hydrogen ions,Evans, Hendrey, Stensland, Johnson, and Francis

presented a third estimate in a recent paper.l2 Thisgroup states:

For aquatic ecosystems, current research indicates thatestablishing a maximum permissible value for the volumeweighted annual H+ concentration of precipitation at 25ueq/1 may protect the most sensitive areas from perma-nent lake acidification. Such a standard would probablyprotect other systems as well.This last estimate is quite similar to the National

Academy estimate; a H+ concentration of 25 ueq/1 isequal to a pH of 4.6.

Maps of the decrease in wet sulfur deposition requiredto reach each of these targets can be derived from themeasured deposition levels presented in figures C-4 toC-6. The three statements can be summarized into fourplausible targets:

1. 20 kg/ha (42 meq/m2) wet sulfate,2. average precipitation pH of 4.6 (25 ueq/1 H+),3. average precipitation pH of 4.7, and4. 50-percent reduction in H+ (hydrogen ion) de-

posited in rainfall.It should be noted that these target values all use wet

deposition as a surrogate for total (wet plus dry) deposi-tion, because of the larger data base from which to drawcomparisons to ecological effects.

1 f NRCIN.AS Atmospfsere.ll;oSplsere Interactions: Toward a BetterUnderstanding of the Ecological Consequences of Fossil Fuel Combustion, Na-tional Academy Press, Washington, D. C,, 1981,

121.. S. Evans, et al , ‘ ‘Acidic DepositIon: Considerations for an Air QualityStandard, Water, Air and Soil Pollution 16, 1981, pp. 469-509,

Several assumptions are required for calculating thereductions in sulfate deposition necessary to reach thelast three target values. First, if wet sulfate levels arereduced, a corresponding quantity of hydrogen ions (inabsolute units, not percentage) must be eliminated topreserve the required charge balance. Second, one mustassume that other ions, especially neutralizing ions suchas calcium and ammonium, will remain at constant lev-els. Both assumptions are reasonable simplificationsgiven the current chemical constituents in rainfall.

Figures C-1 7 to C-20 present maps of the percentagedecrease in wet sulfur deposition required to reach thefour deposition targets. These figures are derived from1980 data—a year in which the annual precipitation wasabout average in most regions. Figure C-17 estimatesregional wet sulfur-deposition reductions needed to meetthe first target value (20 kg/ha wet sulfate). Figure C-1 7shows that to reach this target, wet sulfur depositionwould have to be reduced by about 50 percent in theareas of heaviest deposition, and by over 30 percentacross broad regions of the Eastern United States.

Figures C-18 and C-19 show the wet sulfate-deposi-tion reductions needed to meet target values of averagerainfall pH of 4.6 and 4.7. The more stringent targetof pH 4.7 requires greater than 70-percent decreases inareas of highest deposition. The less stringent targetof pH 4.6 would require reductions about 10 percentsmaller in the peak deposition areas; the required reduc-tion drops by a larger percentage in areas of lower dep-osition.

Figure C-20 displays wet sulfate deposition reductionsneeded to meet target 4—a 50-percent reduction in hy-drogen ion concentration in precipitation. The peakreductions required are on the order of 50 percent, withbroad regions of the Eastern United States requiring wetsulfate reductions of 40 percent to reach this target.

Errors in sampling and chemical analysis lead to un-certainty about the position of the mapped lines show-ing required decreases of wet sulfate. These errors,which might be on the order of 10 percent, would trans-late into uncertainty about the position of the lines byabout 50 to several hundred km,

Year-to-year weather variations could also shift theposition of the lines on the maps. For comparison, pro-jections of decreases in wet sulfur deposition necessaryto meet target values 3 and 4 are shown in figures C-21and C-22. These projections are based on 1979 data,rather than on 1980 data. For both target calculations,the 1979 data show lower required reductions, with thepeak reductions shifted to the northeast. It is not possi-ble to determine how much of the difference is attribu-table to sampling error, the smaller number of samplingstations operating in 1979, or differences in weatherpatterns.

App. C—Atmospheric Processes 293

Figure C-17. —Target Value: Wet Sulfate Loadings of 20 kg/ha-yr

Estimated percent reduction in wet sulfate deposition necessary to reduce wet sulfate loadingsto less than or equal to 20 kg/ha-yr (1980 data)



Figure C-18.— Target Value: Average Precipitation pH of 4.6


Figure C-19.— Target Value: Average Precipitation pH of 4.7

Estimated percent reduction in wet sulfate deposition necessary togreater (1980).

99-413 - 84 - : QL. 3


Figure C-20. —Target Value: 50°/0 Reduction in Hydrogen Ion Deposition

Estimated percent reduction in wet sulfate deposition so that hydrogen ion deposition isreduced by 50 percent (1980 data).

App. C—Atmospheric Processes ● 2 9 7

Figure C-21 .—Target Value: Average Precipitation pH of 4.7

This figure illustrates the estimated percent reduction in wet sulfate deposition necessary toreach the same target value as in fig. C-19—average precipitation pH of 4.7 or greater—however,the estimates are based on 1979 data.


Figure C-22.— Target Value: 50°/0 Reduction in Hydrogen Ion Deposition

App. C—Atmospher ic Processes . 299

As figures C- 17 through C-22 illustrate, the range ofreductions required to reach each of the four targets—and the same target in two successive years—varies con-siderably. However, these figures permit some generalqualitative statements to be made about the wet sulfatereductions needed to reach the suggested targets.

In regions of highest deposition, target depositionreductions range from 50 to 80 percent. For NewEngland, deposition reductions required to reach thetargets vary from about 30 to 70 percent. For sensitiveareas south of the peak deposition region (e. g., thesouthern Appalachians in Tennessee), wet sulfur-dep-osition reductions needed to reach the targets are on theorder of 20 to 50 percent. In the upper Midwest (e. g.,the lake regions of Wisconsin and Minnesota), deposi-tion would have to be reduced by O to 40 percent toreach the targets.

The previous section characterized the uncertaintiesinherent in using models to predict deposition reduc-tions resulting from emissions reductions. Plausiblemodel-based estimates of how much both wet and drysulfur deposition might be reduced by an 8-million toIO-million-ton-per-year reduction in S02 emissions werepresented. Because the deposition targets are expressed

as decreases in wet sulfur deposition, and due to thelarge uncertainties in both sets of analyses, the deposi-tion reductions that might result from reducing S02

emissions can only be compared tentatively to the dep-osition reductions required to meet targets for protect-ing sensitive resources. In areas of highest deposition,for example, western Pennsylvania, the suggested targetreductions to protect sensitive resources might not beachievable with an 8-million to 10-million-ton reduc-tion in S02 emissions; in areas of lower deposition, suchas northern New England, the southern Appalachiansand the upper Midwest, the target deposition reductionsmight be achievable with S02 emissions reductions ofthis magnitude.

Thus, the uncertainties about reaching target deposi-tion levels are greater in those areas that receive mostof their sulfur deposition in wet form (e. g., the Adiron-dack Mountains). As discussed above, for a given levelof S02 emissions reductions, the reduction in wet dep-osition may be less than for dry deposition. Moreover,changes in wet sulfur deposition resulting from a givenchange in S02 emissions may also depend on levels ofsuch co-pollutants as NOX and RHC.

Appendix D

Existing Domestic andInternational Approaches

D.1

D.2

D.3

INTERSTATE AND INTERNATIONALPROVISIONS OF THE CURRENT CLEAN AIR ACT (p. 300)INTERNATIONAL PROGRAMS FORCONTROLLING EMISSIONS OF SULFUR DIOXIDE (p. 305)MITIGATING THE EFFECTS OFACID DEPOSITION ON AQUATIC ECOSYSTEMS (p. 312)

D.1 INTERSTATE AND INTERNATIONALPROVISIONS OF THE CURRENT CLEAN AIR ACT

Provisions in the existing Clean Air Act (CAA) ad-dress both interstate and transboundary pollution; how-ever, the effectiveness of these statutory mechanismsis subject to question. The act also provides affected par-ties with a means to seek remedy for interstate pollu-tion not adequately regulated by existing control pro-grams. It does not directly provide other nations ameans of remedy for transboundary (international) pol-lution; however, actions taken by the previous admin-istration under the act’s international provision mayhave created a right to legal recourse. In addition, ave-nues other than the CAA could potentially be pursuedto remedy transboundary pollution.

Interstate Pollution Control and theClean Air Act

The Environmental Protection Agency (EPA) and thecourts have taken action under the interstate provisionsof the CAA to abate interstate air pollution resultingfrom local sources. However, considerable uncertaintyexists over how these provisions should be interpretedwith regard to longer range transported air pollutants.EPA currently takes the position that analytical tech-niques addressing transported pollutants are not reliablefor regulatory purposes; the courts have yet to rule onthis issue. The statutory language of the interstate pro-visions does not provide a direct means of controllingacidic deposition.

The NAAQS SIP Process

The CAA requires that States adopt implementationplans to: 1) attain and maintain national ambient airquality standards (NAAQS) within their borders and2) prevent significant deterioration (PSD) in areas al-ready meeting NAAQS. Section 110 also spe-cifically requires that State implementation plans (SIPS)include provisions prohibiting any stationary sourcefrom emitting pollutants that would prevent attainmentand maintenance of NAAQS or interfere with PSDmeasures in another State. The Administrator may notapprove a SLP that does not comply with these interstatecontrol requirements.

Utility of the interstate Provision forControlling Transported Air Pollutants

L I M I T A T I O N S O F S E C T I O N l o

Section 110 has several limitations for con-trolling interstate pollution: It applies only to air pol-lution, and offers no direct means of controlling acidicdeposition. It gives little guidance as to how much in-terstate air pollution is prohibited, and does not outlinethe level of proof of causation required to substantiateregulation by EPA. As written, the section leaves opensuch questions as: 1) whether pollution must be linkedto individual sources to justify control, and 2) whetheranalytical techniques (including models) that estimatethe relationship between emissions from ‘‘source’ re-

300

App. D—Exist ing Domest ic and Internat ional Approaches 301

gions and the resulting air quality of “receptor’ regionscan be used to justify regulating individual sources.Finally, the section applies only to stationary sources;it does not control mobile-source emissions.

THE INTERSTATE PROVISION AS APPLIED BY EPA

Since section 110 was enacted in 1977, EPAhas initiated no review of SIPS to assess their compliancewith the provision. The agency has issued no regula-tions to spell out how a State can determine if its SIPcomplies with section 11 O(a)(2)(E). EPA has reviewedand approved a number of revisions to SIPS since 1977,but the agency has not articulated definitive policies fordetermining whether an individual source relaxationcomplies with section 11 O(a)(2)(E). Current EPA pro-cedures, however, limit the scope of SIP review to thatportion of the plan undergoing revision. Hence, whereSIP revisions propose emissions relaxations for individ-ual plants, EPA considers only the local air quality im-pact resulting from the change in emissions for theseplants.

EPA also has taken the position that there are no ade-quate tools to assess long-range transport effects, andEPA practices reflect this position. First, in reviewingemissions 1 imitations with respect to the interstate pro-visions, the agency only considers impacts that can beestimated by models approved under its modeling guide-line. This effectively limits consideration of impacts towithin 50 km of the source, because there are no ap-proved models to estimate long-range transport im-pacts. Second, the agency does not consider potentialimpacts of the transformation products of the pollutantfor which a SIP relaxation is being considered. For ex-ample, the agency reviews the interstate effect of a sulfurdioxide emissions relaxation solely for its impact on sul-fur dioxide air concentrations in downwind states. How-ever, sulfur dioxide also is transformed to particulatesulfates in the atmosphere. Sulfates cause visibility deg-radation, and contribute to total suspended particulate(TSP), for which there are national air quality stand-ards. EPA does not consider the effect of increased sulfurdioxide emissions on total suspended particulate levelsor on visibility.

REMEDIES FOR INTERSTATE POLLUTIONUNDER THE CLEAN AIR ACT

CAA currently contains two means of remedy for in-terstate air pollution. The first relies on general judi-cial review provisions under section 307 allowinglitigants to challenge EPA actions. The second initiallyrelies on administrative review provisions under sec-tion 126, allowing States and political subdivisions topetition EPA on matters dealing specifically with inter-

state pollution. Since 1977, a number of suits and peti-tions have been filed under these provisions of the actto remedy interstate air pollution. Early actions soughtremedy for interstate air pollution in situations wherepollutants were traceable to individual sources in thenear vicinity. In later actions, attention has shifted fromthe ‘ ‘local-source problem’ and focused on interstatepollution allegedly caused by long-range transport.

JUDICIAL REMEDIES: SECTION 307 SUITSINVOLVING THE TRANSPORTED AIR POLLUTANTS

States and other litigants seeking remedies for inter-state pollution have challenged EPA approval of SIP re-visions for single sources under section 307 of the act.In these suits, litigants have attempted to obtain judicialreview of EPA’s practice of not addressing regionalemissions through the SIP process. They also have at-tempted to compel EPA to use models and other tech-niques to assess long-range transport effects.

Litigants have advanced the following reasons forchallenging EPA approval of the SIP revisions: 1 ) theAdministrator failed to properly review the long-rangeeffects of the individual source for which a relaxationwas approved; 2) EPA failed to consider the air qualityimpacts of the transformation products of sulfur dioxide;and 3) the Administrator failed to review the whole SIPto determine whether the cumulative emissions ofsources governed by the SIP do not cause pollution inv io l a t i on o f s ec t i on 110 .

SECTION 126: THE ADMINISTRATIVEPETITION PROCESS

Section 126 is a companion section to 110.It requires States to provide notice to nearby States ofsources that ‘ ‘may significantly contribute’ to air pol-lution in excess of NAAQS. In addition, it provides anadministrative remedy for interstate pollution throughpetition to the EPA Administrator. The section providesin part that:

. . . a State or political subdivision may petition the Ad-ministrator for a finding that any major source emits orwould emit any air pollutants in violation of the prohibi-t i o n o f s e c t i o n 1 1 0 .

Within 60 days of receipt of a petition, the act requiresthe Administrator to hold a public hearing and eithermake such a finding or deny the petition.

PETITIONS UNDER SECTION 126 SEEKINGREMEDY FOR TRANSPORTED AIR POLLUTANTS

States seeking remedy for interstate pollution causedby the long- range transport of emissions from multi-ple sources have fried section 126 petitions in tandemwith suits under section 307. At least nine petitions of


the State of New York, and the petitions of Pennsylvaniaand Maine, have been consolidated into a single pro-ceeding, which places before EPA the gamut of issuesinvolved in the long-range transport controversy.

The consolidated petitions claim that sulfur dioxideand particulate emitted by sources governed by SIPSin Illinois, Indiana, Kentucky, Michigan, Ohio, WestVirginia, and Tennessee are causing interstate pollu-tion in violation of section 110. The petitionersallege that such pollution prevents attainment and main-tenance of NAAQS for both total suspended particulateand sulfur dioxide, and interferes with PSD require-ments. Petitioners further allege that the conversion ofsulfur dioxide to particulate sulfates contributes to theaforementioned problems and, in addition, that sulfatespresent a hazard to health and cause acid rain, resultingin damage to aquatic and terrestrial ecosystems. Mainespecifically claims that transformed products of sulfurdioxide cause visibility degradation in the mandatoryClass I area of Acadia National Park in violation of theact. These three States have asked that EPA review theSIPS for long-range transport effects and have requestedmajor reductions in emissions in the Eastern UnitedStates.

These States have presented extensive information on:the air quality problems and alleged environmentalproblems resulting from acid rain in their States; airquality data and modeling results allegedly demonstrat-ing that interstate pollution contributes significantly tothese problems; air quality models and analytical tech-niques available to assess the long-range transport of airpollutants; the relative stringency of emissions controlsin the Midwestern States versus New York, Pennsyl-vania, and Maine; and finally, the different levels ofemissions limitations that petitioners claim are neededto control interstate pollution.

Extensive comments have been filed concerning theinformation presented by the petitioners and the issuesraised. Although the New York-Pennsylvania-Mainepetitions were filed between fall, 1980, and summer,1981, as yet, EPA has issued no preliminary findingsin the proceeding. Six Northeastern States recently suedEPA (March 1984) to rule on the outstanding petitions,but no court action has yet been taken.

REVIEW AND REMEDIES UNDER SECTION 307, SIPCHALLENGES, AND SECTION 126 PETITIONS

A recent court ruling suggests that the types of reviewobtainable under judicial and administrative remedyprovisions may differ. EPA has asserted, and the Sec-ond Circuit Court of Appeals has ruled, that EPA is notrequired to review the whole SIP for its compliance withthe Act when it reviews proposed revisions amendingonly portions of the SIP. Accordingly, plaintiffs might

not be able to obtain review of an implementation planas a whole in the context of SIP revisions for individualsources. Thus, section 126 administrative proceedingsmay be the only way for States to seek remedy for pollu-tion caused by cumulative emissions from all stationarysources regulated by a SIP.

It is not clear what relief the petitioners could win inthe suits pending before the courts or in the section 126proceedings before the agency; however, a wide rangeof results is possible. Neither route offers a means tocompel direct control of acidic deposition. Litigantsunder section 307 seeking EPA review of SIP relaxa-tions might obtain court decisions requiring the agencyto consider long-range transport effects using ‘ ‘state-of-the-art” techniques. The scope of the New York-Penn-sylvania-Maine section 126 petitions is wider; the peti-tioners could, if successful, win a reversal of EPA SIPreview policies, leading EPA to require broad-scale re-ductions in emissions of sulfur dioxide and particulatefrom Midwestern States.

An appeal from any EPA determination on the NewYork-Pennsylvania-Maine section 126 petition couldcome before the District of Columbia Court of Appeals.Thus, in the absence of further congressional directionto EPA and the courts on long-range transported pol-lutants, the appeals court could become the arbiter ofpollution-transport controversies between the Midwest-ern and Northeastern States.

Control of Transboundary Pollution:The U.S.-Canadian Context

The problems of interstate and transboundary pol-lution control are strongly linked. Winds that transportpollutants over State lines can also carry them acrossthe border between Canada and the United States, fromboth sides. A number of mechanisms are currently inplace for resolving transboundary pollution issues.Means of control are potentially available: 1) througha bilateral accord, 2) under the CAA, and 3) under bothdomestic common law and international law. The ef-ficacy of these mechanisms to deal with transboundarypollution depends substantially on the combined com-mitment of the United States and Canada to controlsuch pollution.

Diplomatic/Legal Context of the U.S.-CanadianTransboundary Air Pollution Issue

The United States and Canada have a long historyof cooperation concerning environmental affairs andjoint commitments to principles for controlling trans-boundary pollution. Beginning with the Boundary Wa-

App. D—Existing Domestic and /international Approaches . 303

ters Treaty of 1909, the two countries have expendedconsiderable efforts to negotiate and/or arbitrate trans-boundary pollution problems, most recently in nego-tiations culminating in the 1978 Great Lakes WaterQuality Agreement. Both the U.S. Congress and theexecutive branch have made repeated commitments tobilateral research, consultation, and negotiations ontransboundary air pollution, as well as to the multilateralDeclaration of the U.N. Conference on the HumanEnvironment (Stockholm Declaration 1972), and the1979 Economic Commission for Europe’s “Conventionon Long-Range Transboundary Air Pollution.

No agreement between the United States and Canadadirectly governs transboundary air pollution; however,cooperative activities have culminated in a Memoran-dum of Intent. 1 Under the Memorandum the two coun-tries have agreed to begin negotiations to reach a bi-lateral accord. The Memorandum also states the twocountries’ commitments to take interim control actions.Although the status of the Memorandum is unclear, itdoes not appear to be legally binding on Canada or theUnited States. Its force derives from the good intentionsof both countries.

The MOI also established several Work Groups toprepare technical information as a background for con-ducting negotiations. Final drafts of three Work Groupreports— impact assessment, atmospheric sciences andanalysis, and emissions costs and engineering assess-ment—were released in February 1983.

U.S. Government officials state that reasonable prog-ress toward reaching a bilateral accord is being made.However, many Canadian officials are dissatisfied withthe progress made in the negotiations and, in 1982,threatened to withdraw from the talks altogether.2 Fed-eral and provincial Ministers of the Environment haverecently pledged to reduce sulfur dioxide emissions 50percent (from 1980 levels) in Eastern Canada by 1994and have urged the United States to do the same. Acidicprecipitation resulting from the long-range transport ofair pollution has emerged as one of the most significantbilateral issues between Canada and the United States.

Transboundary Pollution ControlUnder the Clean Air Act

SECTION 115

Congress adopted section 115 of CAA to provide amechanism for dealing with transboundary air pollu-

1 Memorandum of Intent between the Government of Canada and the(;uvernment of the United States of America concerning Transboundar}, AirPollution, Aug 5, 1980

‘I. , Mosher, ‘ ‘Congress May Have to Resolve Stalled L’ S -Canadian AcidRain Negotiations, ,VatlonafJourrral, Mar 13, 1982, p 456, ‘ ‘Canada MayEnd Talks With U.S for Accord to Combat Acid Rain, The Wall Streer,Jour-nal, June 16 , 1982 , pp 1-7, COl 3

tion. The section is invoked by the Administrator ofEPA on his own initiative or at the request of the Sec-retary of State. The Secretary must allege, or the Ad-ministrator must determine, that pollution emitted inthe United States causes or contributes to air pollutionthat ‘‘may reasonably be anticipated to endanger publichealth or welfare in a foreign country. The section pro-vides that the Administrator can make such a determina-tion ‘‘upon receipt of reports, surveys or studies fromany duly constituted international agency”; however,it does not specify how the Secretary of State will be ap-prised of a problem.

Once the Secretary of State has requested the Admin-istrator to activate the section 115 process, or the Ad-ministrator has made a finding of ‘endangerment, thestatute requires the Administrator to give formal noticeto the Governor(s) of the State(s) in which the emissionscausing the pollution originate. The Administrator musttake this step, however, only if he “determines theforeign country receiving the pollution has given theUnited States essentially the same rights with respectto the prevention or control of air pollution occurringin that country as is given that country by [section1 15]. “ Thus the Administrator must make a determina-tion of reciprocity y to trigger the mandatory duty undersection 115.

Section 115 relies on the SIP revision process as themeans to abate international pollution prohibited by thesection. Section 115 provides that notice given to thegovernor constitutes a finding with respect to section110(a)(2)(E)—i.e., that the State implementation planis inadequate to comply with the requirements of theCAA and must be revised.

UTILITY OF SECTION 115 FOR CONTROLLINGTRANSPORTED AIR POLLUTANTS

Section 115 can be construed to permit the controlof transboundary pollution caused by acidic deposition.However, the language of section 115 provides no guide-lines on how to implement the section. It does not detailthe procedures for the Administrator to follow in iden-tifying which State or States are the source of the trans-boundary emissions, and offers no guidance on allocat-ing control responsibilities when emissions from morethan one State create transboundary problems. The leg-islative history of section 115 is also silent on these issues.

EPA’s current practices for reviewing the SIP con-trol of interstate pollution, if applied to transboundarypollution, would limit the efficacy of section 115 for con-trolling possible acidic deposition and air pollution inCanada. As yet, EPA has not chosen to activate thetransboundary pollution control provision of the act.


ACTIVITY UNDER SECTION 115

The Mitchell Request. —The Canadian Clean AirAct was amended by unanimous vote in both Housesof Parliament in December 1980 to provide clear author-ity for the Canadian Federal Government to take stepsto control the emission of pollutants affecting anothercountry. The amendment was designed primarily toallow “mutual recourse between Canada and the UnitedStates. ”

On December 23, 1980, Senator George Mitchell ofMaine sent letters to the Administrator of EPA and theSecretary of State calling their attention to the recentlyenacted legislation, and to reports prepared by the In-ternational Joint Commission (IJC) and the U.S.-Can-ada Research Consultation Group on Long-RangeTransboundary Air Pollution (RCG). The Senator re-viewed the information in the reports and concluded hisletters with a strongly worded request that action betaken under section 115.

The Costle Response: Determination To ActivateSection 115. —In January 1981, Administrator Costleof EPA responded to the Mitchell request and sent let-ters to both the Senator and the Secretary of State an-nouncing his findings, 3 He found, based on his reviewof the IJC reports and CAA, that section 115 could beactivated to control acidic deposition in Canada. He alsodetermined that the Canadian Clean Air Act providesCanada with authority to give the United States essen-tially the same rights as Canada under section 115, andthat at present Canada was so interpreting the act. Henoted that this second aspect of EPA’s determinationis necessarily a dynamic one and would continue to beinfluenced by Canadian actions. Thus, having made therequisite determination to activate section 115, the Ad-ministrator instructed EPA staff to begin work to iden-tify which States should receive formal notification, andto lay the groundwork to assist those States in ap-propriately revising their SIPS.

There have been no indications that the work initiatedby Administrator Costle is proceeding under the pres-ent EPA administration. As yet, section 115 notifica-tion has not been given to any State, and EPA appearsnot to have continued the process leading up to notifica-tion. EPA has issued no statement, however, that re-verses the Costle determination. No court has yet re-viewed the legal significance of Costle’s action.

Remedies for Transboundary Pollution

RECOURSE UNDER THE CLEAN AIR ACT

The initial decision to activate section 115 clearly isdiscretionary. Thus, the statute does not explicitly pro-

‘Letters from Douglas Costle, EPA Administrator, to Edmund Muskie,Secretary of State, Jan 13, 1981, and to Senator George Mitchell, Jan. 15, 1981.

vide a course of action that Canada or others could pur-sue in domestic courts to remedy transboundary pol-lution. An argument can be made, however, that theactions of former Administrator Costle ‘‘activated’ sec-tion 115 and created a legal obligation for the presentAdministrator to revise SIPS to control acidic deposi-tion in Canada.

Section 304 of CAA authorizes “any person” to bringsuit to compel the Administrator to perform nondiscre-tionary duties under the act. Under this citizen suit pro-vision a number of different groups could bring suit tocompel action under section 115—among them are en-vironmental organizations and Northeastern States thatmight “benefit’ from activation of the section, The eli-gibility of Canada or the Province of Ontario to bringsuit is less clear. Section 302(e) does not specifically men-tion foreign governments, and the issue of whether for-eign governments are considered to be ‘‘persons’ undersections 302(e) and 304 remains unsettled.4 However,standing to sue would not be a barrier to litigation byplaintiffs having interests similar to those of Ontario orCanada.

If a suit were initiated under section 304 to compelthe present Administrator to notify States under section115 to revise their SIPS, a court could be faced with thequestion of whether Costle’s determinations were arbi-trary and capricious, or in excess of statutory authorityand, as such, unlawful. The present Administratorwould have the burden of convincing a court that theprevious Administrator’s determinations were invalid.Since the statute gives the Administrator great discre-tion, and courts as a rule defer to administrative deter-minations, this would be a difficult burden to overcome.

RECOURSE THROUGH DIPLOMATIC CHANNELS

The Canadian Government could choose to link thetransboundary issue to other areas of bilateral concernin an effort to encourage adoption of policies to reducethe long-range transport of air pollution. Canada is animportant ally and neighbor. The United States’s in-volvement with Canada is probably greater than withany other foreign country. The two-way trade is about$77 billion, which is greater than that between theUnited States and all the countries of the EuropeanCommunity. The two countries are allies in NATO and

~It can be argued that foreign governments are considered to be ‘ ‘persons’under sees 302(e) and 304. Sec. 302(e) could be construed as inclusive of possi-ble litigants rather than defining the complete set. Such a construction wasplaced on a similarly worded definition under the antitrust laws and thus thedefinition in the statute was not a mandate to reverse the longstanding presump-tion that f’oreign nations are entitled to sue in courts of tbe United States Pfizer,Inc. v. Government of India 434 U.S. 308 (1978). Accordingly the Court in

Pfizer found that India was a “person” within the meaning of sec. 4 of theClayton Act in spite of the fact that the section did not include foreign govern-ments in the list of those authorized to sue.

App. D—Exist ing Domest ic and Internat ional Approaches . 305

have a unique military joint command, the North Amer- In practice, however, domestic common law may not,ican Air Defense Command. and international law does not, provide an effective

means to compel U.S. control efforts. In the case ofRECOURSE UNDER DOMESTIC COMMON LAW domestic common law, recent court decisions as well

AND INTERNATIONAL LAW as problems surrounding proof-of-causation may limit

In theory, domestic common law and international the use of this avenue; in the case of international law,

law also provide a means of legal recourse should Can- there are no effective means to enforce legal doctrines.

ada or others be dissatisfied with U.S. control efforts.

D.2 INTERNATIONAL PROGRAMS FORCONTROLLING EMISSIONS OF SULFUR DIOXIDE

As in the United States, air quality laws in WesternEurope, Canada, and Japan focus primarily on ambientconcentrations of air pollutants within the locale of emis-sion sources, rather than on pollutant deposition. How-ever, over the past decade, increasing awareness of aciddeposition as a potential problem has led several coun-tries to develop and adopt further control policies. Work-ing within the existing regulatory framework for con-trolling sulfur dioxide (S02), Canada, West Germany,and the Scandinavian countries have initiated furtherS 02 emissions limitations and restricted the level ofsulfur in fuel in order to address acid deposition.

European nations have established extensive cooper-ative monitoring programs to gather information on thenature and extent of acid deposition and other trans-ported air pollutants. Some accords dealing with trans-boundary pollution have been reached, and negotiationsare in progress in others.

This appendix describes the international organiza-tions and accords that deal with transboundary pollu-tants. In addition, it outlines the existing policies of thecountries of Scandinavia, the United Kingdom, WestGermany, Canada, and Japan concerning acid rain andtransboundary air pollution.

International Organizations andAccords Dealing With Transboundary

Pollution

Considerable international effort has been expendedto address transboundary air pollution and acid rainover the last decade. At the urging of the Scandinaviancountries, transboundary pollution problems have beendiscussed in such international forums as the U.N. Eco-nomic Commission for Europe (EC E), the EuropeanEconomic Community (EEC), and the Organization for

Economic Cooperation and Development (OECD);these organizations have also launched research effortsto study the problem. In March 1984, EnvironmentalMinisters from nine European nations and Canadasigned an agreement to reduce national sulfur dioxideemissions at least 30 percent by 1993 in an effort to curbtransboundary air pollution. The countries signing theagreement—referred to as the ‘‘30 percent Club —were Canada, Austria, Denmark, West Germany, Fin-land, France, the Netherlands, Norway, Sweden, andSwitzerland. They also agreed to urge that othersignatories to the Convention on Long Range Trans-boundary Air Pollution of the UN Economic Commis-sion for Europe (ECE) take similar action.

Economic Commission for Europe (ECE)and the Convention on Long-RangeTransboundary Air Pollution

The ECE, comprised of all European United Nations(U. N.) members plus Canada, the United States, andthe U. S. S. R., is one of five regional economic commis-sions of the U. N. It began to address the transbound-ary pollution issue as early as 1969, when a workinggroup on air pollution recommended reducing SO2

emissions. ECE negotiations began in 1977, with Swe-den and Norway pressing members to, at a minimum,hold S02 emissions to current levels, and to lay thegroundwork for abating S02 levels by a fixed percent-age.

In 1978, the Committee of Senior Advisors to theECE established the Special Group on Long-RangeTransboundary Air Pollution, instructing the group todraft proposals for the consideration of future senioradvisory sessions. Extensive negotiation produced a con-vention substantially modified from that originally pro-posed by the Nordic countries; the modified convention


was accepted at a high-level meeting of the ECE inNovember 1979. The ECE convention was the first mul-tilateral agreement to address specifically the problemof transboundary air pollution caused by long-rangetransport, and was the first major environmental accordinvolving the nations of Eastern and Western Europeand North America.

The accord requires the signing countries to developpolicies and strategies ‘‘as far as possible’ to reduce airpollution gradually, including long-range transboundaryair pollution, employing “best available technologywhich is economically feasible. The convention defineslong-range transboundary pollution as pollution travel-ing to another nation from such a distance that ‘‘it isnot generally possible to distinguish the contribution ofindividual emission sources or groups of sources.While the convention clearly addresses acid deposition,it mandates no emission limitations. Since the conven-tion does not establish numerical goals, limits, or time-tables, or contain enforcement provisions, the signingcountries do not have to alter their pollution-control pol-icies unless they choose to do so.

However, the convention is important as a basis forcoherent research and international management oftransboundary pollution. The signatories agreed tocooperate in conducting research on control technolo-gies, monitoring and modeling techniques, and effectsof air pollutants (e. g., sulfur compounds) on humanhealth and the environment. The ECE countries agreedto exchange information for advancing international re-search efforts such as data on emissions and results ofdomestic research efforts, and further agreed to supportthe ongoing international monitoring program estab-lished by the U.N. Environment Program. This pro-gram has established monitoring sites to measure S02

and particulate sulfate in the air, and acidity inprecipitation, with stations in some 20 Europeancountries.

The European Economic Community (EEC)

The EEC was formed in 1957 and presently includesten European countries of the Common Market—WestGermany, France, Italy, Belgium, the Netherlands,Luxembourg, Ireland, the United Kingdom, Greece,and Denmark. The EEC was formed initially to dealwith economic issues among member countries; how-ever, it has also been used as a forum for discussing in-ternational air quality issues. While the EEC has neverdirectly addressed the long-range transboundary air pol-lution issue, it has developed and issued directives deal-ing with S02 emissions generally. A directive on the sul-fur content of certain liquid fuels was issued in 1975;a directive establishing health protection standards for

S02 was submitted to the governing Council of Minis-ters for approval in 1976 and was finally adopted in1980. The standards are relatively lenient by comparisonto current World Health Organization and U.S. stand-ards. The directive requires that member countriesadopt measures to meet the standards by April 1983,but allows nonattainment areas 10 years to achieve com-pliance.

The directive also requires countries to establish anair-quality monitoring network, and establishes com-mon procedures for the network and for exchanging dataand information. Although the EEC directive does notdirectly address long-range transport and acidic depo-sition, the resolution accompanying the directive is anindication of the EEC awareness and concern for theseissues. In language similar to the ECE Convention, theresolution states that EEC members:

. . . will endeavor, in accordance with objectives of theabove mentioned Directive, and taking due account ofthe facts and problems involved, to limit, and, as far aspossible, gradually reduce and prevent transboundary airpollution . . .The EEC directive is more significant as a symbol

of commitment to controlling transboundary and do-mestic air pollution than as a means of implementingcontrol measures for S02. Less than 5 percent of EEC’sland mass will exceed the health standard in 1983, De-spite the goals of the EEC directive, it appears to dolittle to further the role of either the EEC or its membersin reducing and preventing transboundary air pollution.

The Organization for EconomicCooperation and Development (OECD)

The OECD was founded in 1961 as a ‘ ‘Western’ al-liance for promoting economic growth. Its members in-clude the United States, Japan, Canada, West Ger-many, the United Kingdom, and the Scandinaviancountries. Although all decisions within the OECD arenonbinding, the Organization has been highly influen-tial in developing international law and policy concern-ing transboundary air pollution. The OECD has alsoproduced some important research on transported airpollution.

In 1972, the OECD established the “CooperativeTechnical Program to Measure the Long-Range Trans-port of Air Pollutants. The program measured S02

emissions in 11 European countries, as well as air con-centrations of S02, particulate sulfate, and sulfate inprecipitation. Computer models were used to estimatedomestic and foreign contributions to each country’ssulfur deposition. The effort, coordinated by the Nor-wegian Institute for Air Research, was among the firstto rely extensively on long-range transport models; re-

App. D—Existing Domestic and International Approaches . 307

suits were published initially in 1977 and in an expandedversion in 1979. The study concluded that more thanhalf of the deposition in five countries was caused bytransboundary pollution.

The OECD has also produced reports on the legalaspects of transboundary pollution. By adopting thePrinciples Concerning Transfrontier Pollution theOECD Council urged member countries to followguidelines in developing international law to deal withtransfrontier pollution. Specifically, the Principles rec-ommend: 1 ) a country in which transboundary pollu-tion originates should address the problem as it wouldif the pollution occurred within its borders; 2) equalrights should be granted to foreigners in administrativeand judicial proceedings; and 3) other nations shouldbe informed of actions that a country believes might in-crease transboundary pollution. In addition, the Councilalso espoused the principle that the producers of pollu-tion should pay for its control even when effects are feltoutside the country of origin.

The Nordic EnvironmentalProtection Convention

In 1974, Finland, Denmark, Norway, and Swedensigned the Nordic Environmental Protection Conven-tion. The convention essentially eliminates internationalboundaries with respect to controlling pollution fromstationary sources, and can be construed to deal withacid deposition from transboundary pollution. In manyrespects the Nordic Convention resembles the principleson transboundary pollution approved by the Councilof OECD. It provides that permit decisions for pollu-tion sources should weigh any adverse effects the sourcemight have on a foreign country as though such effectswould occur domestically. The Convention also adoptsthe principle that a foreigner has a right to institute pro-ceedings in the country of emission concerning the per-missibility of the emissions and to seek compensationfor damages.

Multilateral European Monitoring Efforts

international research efforts in Europe began overa decade ago. Three monitoring networks have providedinformation on air and precipitation chemistry on long-range transport of air pollutants: the European Atmos-pheric Chemistry Network (EACN), the Organizationfor Economic Cooperation and Development Study onLong Range Transport of Air Pollutants ( O E C D /LRTAP), and the Economic Commission for Europe’scooperative program for monitoring and evaluatingtransported air pollutants in Europe (EC E-EMEP).

The EACN, begun in 1950 by Swedish scientists,consisted at its peak of 120 stations in 12 countries

analyzing air quality and wet deposition monthly. Datafrom this network showed an expanding area with highlyacidic precipitation and led to the creation of OECD/LRTAP, operating from 1972 to 1977.5

Results of OECD/LRTAP suggested that future stud-ies should include all European countries. EMEP, or-ganized under ECE, in cooperation with the United Na-tions Environment Program (UNEP) and the WorldMeteorological Organization (WMO), was begun in1977. Its main objective is to ‘ ‘provide governmentswith information on the deposition and concentrationof air pollutants, as well as on the quantity and signif-icance of long-range transmission of pollutants andtransboundary fluxes.6

About 65 stations in 20 European countries are cur-rently in operation. The monitoring sites have beenselected primarily to represent rural areas. The EMEPsampling network relies principally on 24-hour samplingof S02 and particulate sulfate in air, and sulfate andacidity in precipitation. In addition, nitrate and ammo-nium in precipitation are measured in more than halfthe countries. The EMEP program is projected to issuesemiannual reports for several years.

Approaches to SO2 Control in Canada,Scandinavia, West Germany, theUnited Kingdom, and Japan

CANADA

Acid rain has become a major public policy issue inCanada. Particularly in the Eastern Provinces, there isdeep and widespread concern over the possible dam-age to Canadian lakes and forests, and to the extensivetourist, recreational, and forestry industries they sup-port. Due to transboundary transport of pollutants be-tween the United States and Canada, acid rain has be-come a major issue in relations between the twocountries.

Total S02 emissions in Canada in 1980 were about5.3 million tons a year, approximately one-fifth theamount emitted by the United States. Most of theseemissions come from two source categories: nonferroussmelters and coal-fired utilities. Although utilities con-tribute much less to Canada’s total S02 emissions thansmelters, Canadian powerplants could have a dispropor-tionate effect on transboundary pollution because themajority of plants are located close to the U.S. border.

Canada and the United States are formally committedto developing a bilateral strategy to control transbound-

5 1 . Granat, ‘‘Sulphate m Preclpltatkn as Obsen,ed by the European At-mospbcrlc Cbemmtry Network, ” Atmosphem- Ent,ronmenr 12, 413-424, 1978

‘H. Douland, ‘ ‘European Networks—Operation and Results, Sulfur /n (heAtmosphere, Proceedings of an Intcrnatlonal S},mposlum In Dubrovnik, Yu-goslavla$ Sept 7-14, 1977


ary air pollution. In August 1980, the two nations signeda Memorandum of Intent (MOI) establishing five scien-tific and technological workgroups and pledging bothcountries to formal treaty negotiations. Three of the fiveworkgroups under the MOI have completed their workand released their results on February 22, 1983.

Canadian air pollution control programs tend to beundertaken flexibly, with minimum use of formal legalmeasures, emphasizing government/industry coopera-tion instead. The legal basis for controlling air pollu-tion in Canada lies in its Clean Air Act, most recently“amended in December 1980. Although the act now pro-vides the Canadian Federal Government with the au-thority to control transboundary pollution originatingin Canada, the Federal role is mainly one of guidanceand demonstration to the relatively autonomousProvinces.

The Canadian Clean Air Act of 1980 exhibits distinc-tive differences from, but important similarities to, theU.S. Clean Air Act:7

●

●

●

●

●

●

The national ambient air quality objectives con-tained in Canada’s Clean Air Act, like those of theUnited States, are concerned primarily with local,ground-level effects, rather than regional or long-range transport impacts.As in the United States, the act does not directlyaddress sulfates and nitrates (the main componentsof acid deposition), because they are largely formedin the air, rather than being emitted directly.Unlike those of the U.S. Clean Air Act, Canada’sFederal standards are only guidelines and are notbinding on Provinces. The Provinces have abso-lute discretion in the Canadian regulatory process.The Provincial governments often negotiate withindustry to attain emissions reductions. Canadiancourts are not involved in this process.Not all Provinces of Canada have adopted ambientstandards. Standards for those that have—Alberta,Manitoba, New Brunswick, Ontario, and Sas-katchewan—are far more stringent than the com-parable U.S. primary standards.Cost effectiveness is a major consideration in de-veloping most Provincial air pollution control pro-grams. Less costly measures, such as the use of low-sulfur coal, and dispersion techniques such as tallstacks and siting, are the major means used to avoidexcessively high ambient concentrations from pow-erplants. No scrubbers are in use in Canada today.The Canadian Clean Air Act empowers the Fed-eral Government to set national guidelines only for

.—7G. Wetstone, “Review of Approaches to Long-Range Transport Control

m the United States, Canada, Europe, and Japan, report prepared by theEnvironmental Law Institute for the OTA, March 1981

new sources and pollutants determined to havehealth effects. These guidelines are not mandatory.

● In 1981, Canada passed a program for coal-firedpowerplants analogous to U.S. New Source Per-formance Standards. Other new sources are not asstringently controlled; emphasis has focused oncontrolling existing sources.

The Canadian Parliament, in December 1980,amended the Canadian Clean Air Act to grant the Min-ister of the Environment authority to recommend site-specific standards for sources ‘‘that may reasonably beanticipated to constitute a significant danger to thehealth, safety, or welfare of persons in another coun-t r y . Provinces are given the first opportunity to en-force standards to “eliminate or significantly reduce”transboundary pollution. The Government-in-Council(essentially, the Federal Cabinet) may implement thestandards if the provinces have not acted expeditiously.8

In March 1984, federal and provincial Ministers ofthe Environment agreed to reduce S02 emissions by 50percent in eastern Canada by 1994, using 1980 as a basecase year.

Formerly, Canada had been committed to a 25 per-cent emissions reduction east of Saskatchewan by 1990to be achieved primarily by controlling Ontario Hydroand the International Nickel Co. (INCO) smelters.

Ontario Hydro, the provincially controlled utility sys-tem and largest aggregate source of utility emissions inCanada, was to reduce total S02 and NOX emissions43 percent from 1982 levels.

Ontario’s Government-in-Council (i.e., the Provin-cial Cabinet) restricted emissions from the largest singlesource of Canada’s S02, INCO’s massive smelters atSudbury, Ontario, to 1,950 tons/day in 1983. This rep-resented a decrease from a maximum of 7,200 tons perday in the late 1960’s.9

The control measures imposed on INCO, and On-tario Hydro may be changed when implementationplans for the recent decision to reduce emissions 50 per-cent in eastern Canada are developed.

SWEDEN

Swedish authorities consider acidification to be themost serious environmental problem of the decade, andare continuing their efforts both in Sweden and inter-nationally, to reduce acid deposition. Of about 85,000Swedish lakes classified as medium to large in size, morethan 18,000 are currently acidified. About 4,000 of themare very seriously acidified and have suffered extensivebiological damage. In about 9,000 lakes, mainly in

‘Clean Air Act 522.1, House of Commons 1st Session, 32d Parliament, 29Elizabeth II, 1980, Bill 151.

‘Written communications from Bruce Jutzi, First Secretary, Embassy of Can-ada, Mar. 10, 1983, and Sept 13, 1983.

App. D—Existing Domestic and International Approaches ● 309

southern and central Sweden, damage to fish stocksrange from minor upsets in lifecycles to extinction oftrout and crayfish species. 10 Swedish scientists believethat several thousand more lakes will be threatened ifacid deposition continues at present rates.

Sweden has decided to control its own S02 emissionsstringently, although it is estimated that 70 percent ofSweden’s pollutant deposition originates from sourcesoutside the country. Since the early 1970’s, when theproblems of acidification first attracted notice, Swedenhas introduced emission controls that have loweredemissions substantially in recent years. In 1970, S02

emissions in Sweden totaled about 450,000 metrictons (tonnes). Currently, Sweden is emitting about250,000 tonnes of S02 a year. New control limits forpowerplants effective October 1, 1984, will set max-imum emissions of 0.24 gram of sulfur/megajoule offuel—about 1.1 lb SO2/million Btu fuel burned. Nine-teen of twenty-four Provinces in Sweden currently meetthat standard.

In the spring of 1981, the Swedish Parliament adoptedan interim measure limiting maximum emissions of sul-fur from any installation to 1,600 tonnes/day. This emis-sions cap has required two flue-gas desulfurization(FGD) units to be installed on a 400-megawatt (MW)and 700-MW powerplant. The Swedish Parliament hasset a goal of reducing industrial sulfur discharges from200,000 tonnes of S02 a year to half that amount by1985. According to Sweden’s National EnvironmentalProtection Board, emissions probably will be reducedto about 85,000 tonnes by 1985. A special committeeon coal, health, and the environment is currently pre-paring a report expected to lead to new proposals fora much lower industrial emissions standard in the springof 1984.

Sweden has also embarked on an ambitious limingprogram to restore acidified lakes. A total of 3,000 lakes,3,000 kilometers of streams, and 500 watersheds havebeen limed from the program’s inception through July1983. Total program costs have reached $17 million todate, including approximately $4 million to lime 500lakes in fiscal year 1983. The program is financed bya tax on fuel oil. Although liming has been shown tobe successful in temporarily preventing acidification andrestoring natural acidity to surface waters, the SwedishGovernment has adopted the policy that liming is a stop-gap measure and cannot substitute for controlling acidi-fying emissions at their source.11

NORWAY

Norwegian officials currently consider acid depositionto be their single most significant pollution problem. Ex-tensive acid-deposition damage has been found inSouthern Norway, where recent studies of 5,000 lakeshave shown losses of fish populations in 1,750 lakes, withanother 900 lakes projected to undergo serious acidifica-tion. As much as 90 percent of Norway’s acidic deposi-tion has been estimated to originate from sources out-side its borders—the highest estimated percentage ofpollution import of any European country.12

Overall emissions of S02 have been reduced in Nor-way following the enactment of new fuel-sulfur limita-tions in the late 1970’s. Under the Neighbor Act of 1961,air pollution sources are required to use fuel oil witha maximum sulfur content of 2.5 percent (about 2.7 lbSO2/million Btu). Amendments to the act in 1977 and1979 imposed a maximum sulfur content of 1 percent(about 1.1 lb S02/million Btu) for all fuel oils used bynew sources or by expansions of existing sources. In ad-dition, existing sources were required to reduce annualS02 emissions by 20 percent from 1977 emissions lev-els.13 These more stringent requirements apply only tothe nine southern and most populated counties of Nor-way. Further reductions in S02 emissions are expectedover the next 5 years; however, Norwegians assert thatno national-level controls will be sufficient to rectify thedamage to their environment caused by acid deposition.

Norwegian concern over the effects of acid precipita-tion prompted major government-sponsored researchbeginning in 1972. The multidisciplinary research proj-ect, entitled ‘‘Acid Precipitation—Effects on Forests andF i s h , culminated in an International Scientific Con-ference in March 1980 in Sandefjord, Norway. Norwe-gian officials believe that reports from this conferenceconclusively link emissions of S02 to environmentaldamage.

Over the past 10 years, the Norwegian Governmenthas worked to achieve a gradual reduction of total sulfuremissions from the member countries of the ECE. Thisgoal was most recently articulated at the Stockholm 1982Conference by Wenche Frogn Sellaeg, Norwegian Min-ister of the Environment, who called for: 1) reducingsulfur emissions in the countries of Europe and NorthAmerica, and 2) ensuring that no new powerplant orindustrial source is constructed without effective con-trols on sulfur emissions.

12w~r,tt(.n ‘Ommunlca[lon from Stein Seeberg, Counselor, ROY~ No~egian

‘0’ ‘Acldlficatmn I“oday and Tomorrow, Swedish Ministry of Agriculture, Embassy, Sept 7, 1983

En\lronment 1982 Committee, 1982, pp. 50 and 130. ‘3’ Norwegian Strategies and Policles for the Abatement of Air PoHutmn11~’rltten ~ommunication from Car] Johan Llden, Counselor, Embass) of Caused by Sulphur Compounds, .4 fajor Government Review of 1982, Oslo,

Swecien, Jan 7, 1983 June 1982


DENMARK

Unlike other Scandinavian countries, Denmark con-tains large areas with soils capable of buffering the highlevels of acid deposition it receives. However, Danishresearchers have found evidence of lake acidification insome poorly buffered areas. Acting on this evidence,Federal and local government officials, along with powercompany executives, have formed a task force to exam-ine ways to reduce emissions of S02 and NOx.

Denmark emits about 450,000 tonnes of S02 an-nually. Two-thirds of these emissions come from oil-fired powerplants and oil-heated homes. Half of allsulfur deposition in Denmark is thought to originate inother countries, principally West Germany and theUnited Kingdom.

Denmark is presently in the midst of major switchesfrom oil to coal use, but this fuel change is expected tocause S02 emissions levels to decline. Oil containing upto 2.5 percent sulfur has met over 80 percent of Den-mark’s energy needs since the early 1970’s. The im-ported coal replacing the oil will have a much lowersulfur content. However, maximum allowable sulfurlevels for coals have not yet been established.14

Denmark’s air pollution is regulated by the Environ-mental Protection Act of 1973. The act sets standardsfor maximum sulfur levels for oils at 0.8 percent for lightoil and 2.5 percent for heavy oil (about 0.9 and 2.7 lbSO2/million Btu, respectively). A stricter limit of 1.0percent for all oil was established in the metropolitanarea of Copenhagen. The act is implemented by mu-nicipal and county authorities under the guidelines ofthe National Agency for Environmental Protection. Theact required major polluters to receive permits from themunicipal or county officials.

Although Denmark is mainly concerned with reduc-ing emissions to levels that do not contribute to adversehealth conditions in the country, it is actively partici-pating in developing international-level controls. Den-mark cosponsored the draft proposal that led to the ECEConvention on Long-Range Air Pollution in November1979.15

THE FEDERAL REPUBLIC OF GERMANY

West Germany is the second largest producer of S02

in Western Europe, and is believed to be a substantialcontributor to acid deposition in Scandinavia. West Ger-many has established an ambitious air pollution con-trol program. It is currently the only country in Europeto rely on scrubbers to abate sulfur pollution from newsources and presently operates eight FGD units.

I+ Written communication with Evy Jordan, Vice Consul, ROYd Danish Em-

bassy, Oct. 1, 1982,151bld

Air pollution in West Germany is regulated under theFederal Emission Protection Act of 1974 (FIPA). Em-bodied in the Act are detailed nonbinding guidelines en-titled ‘ ‘Technical Instructions for Air’ or TA-Luft. Theresponsibility for meeting these requirements rests witheach State or “Lander.” Legislative proposals are underconsideration to make the TA-Luft legally binding onthe Landers.

The first phase of planned revisions to FIPA was ap-proved by the Bundesrat on February 4, 1983. In par-ticular, the new regulations reduce S02 emissions limitsfor new sources by about 35 to 40 percent. It is esti-mated that this will reduce West Germany’s emissionsfrom electricity generation by 1 million tonnes by 1988.

West Germany emitted about 3.9 million tonnes ofS02 in 1982, primarily from coal-fired powerplants andfrom industries burning oil and coal. West Germanyis also believed to receive substantial amounts of pollu-tion from other nations: about half of the sulfur depos-ited in West Germany is estimated to be of non-domesticorigin.16

In recent years, environmental officials and the gen-eral public have become increasingly concerned aboutthe possible effects of acid deposition on German for-ests.17 Because forestry is one of the country’s leadingindustries, recent reports that air pollution—both localand transported— is severely damaging the nation’spine, fir, and spruce trees have aroused major concern.In response to this new evidence, the Federal Govern-ment has recently passed (July 1983) an ordinance onlarge firing installations to reduce total S02 emissionsby 50 percent over the next 10 years. Additionally, WestGermany has recently shifted its position from oppos-ing international accords to promote control of trans-boundary air pollution to willing participation in inter-national efforts.

UNITED KINGDOM

The United Kingdom is the largest emitter of S02

in Western Europe and is believed by some scientiststo be the largest contributor to acid deposition in Scan-dinavia. An OECD study concluded that the UnitedKingdom is a significant exporter of pollutants to down-wind nations, and calculates that it is the largest con-tributor of acid deposition to Norway, as well as thesecond-largest outside contributor of acid deposition toSweden, after West Germany.

Instatement by th e Feder~ Republlc of Germany’s Interior Minister at the

“Conference on Acidification, ” Stockholm, June 27, 1982.ITWrltten communication with Dedef Boldt, Aug. 23, 198216 Elam, “Present and Future Levels of Sulfur Dioxide Emissions in North-

ern Europe, prepared for the Swedish Ministry of Agriculture, June 1979,

App. D—Exist ing Domest ic and Internat ional Approaches ● 3 1 1

Air pollution regulations in the United Kingdom dateback to the Alkali Act of 1863, and are based on theconcept of regulating emissions via the ‘ ‘best prac-ticable’ means of control. The approach is designed toallow flexibility and evolving standards as control tech-nologies improve —a wide range of emission standardsare enforced by a central government inspectorate.However, for SO2 and NOX emissions, Britain’s prin-cipal control strategy is dispersion. Backup strategiesinclude regional use of low-sulfur fuel, coal washing,siting industrial plants in nonurban areas, and develop-ing nuclear power. FGD is not used to control S02 inthe United Kingdom at the present time.

Britain relies on coal to produce almost 70 percentof its electric power, and powerplants account for almost60 percent of its total S02 emissions. Total S02 emis-sions in the United Kingdom have already declined dur-ing the past 10 years from 6 million to 4.5 milliontonnes; they are estimated to remain about constant orpossibly decrease slightly in the future.

The British Government takes the position that sig-nificant uncertainties exist about the atmospheric pro-cesses leading to acid rain formation and about itsreported effects. It asserts that more research is neededbefore a firm case can be established for policies to fur-ther reduce S02 emissions. However, international ac-tion within the UNECE convention, the Stockholm 1982Conference, and the EEC may influence future U.K.policy with regard to transported air pollutants.19

JAPAN

Although Japan is not typically a focus of discussionfor long-range transported air pollutants, its stringentcontrol program and success in reducing ambient con-centrations make it worth noting. Japan has the mostrigorous S02 control policies in the world. Control re-quirements are geared to an ambient standard of 100µg/m3 for a daily averaging time, compared to the U.S.standard of 365 µg/m3. In 1981, 98 percent of themonitoring stations in Japan met that standard. In 1974,

i ~~~,~,[(~n ~fl~~Un,c ~cl”~ from Mike Norton, F’mst Secretary, Embassy of

(jreat Britain, Aug ? 0 , 1982

Japan instituted an emissions fee for large S02 sourcesin polluted areas. The proceeds are used in designatedareas for the medical care of patients affected by air pol-lution.

About 1,362 FGD units were in operation in Japanduring 1982. Most are small units installed primarily

on industrial plants producing chemicals or pulp andpaper products. Sixty-three of the units are installed onpowerplants, accounting for 40,000 MW of electricalgenerating capacity. Unlike the United States and WestGermany, where coal-fired plants are the focus of FGDcontrols, 29 of the Japanese units have been installedon coal-fired boilers and 34 on oil-fired plants. 20

According to the Japanese Government, these FGDunits have not created a sludge disposal problem,because such materials as gypsum produced by scrub-bers have been highly salable in Japan. The use of FGDwas in fact promoted by the short supply of sulfur ma-terials, creating a favorable market for these products.However, rapid expansion in the production of thesegoods has recently outstripped the market demand,which may make scrubber-byproduct disposal a land-use problem. Other countries are now beginning tofollow Japanese techniques for regenerating FGDsludge.

Government subsidies and the expansion of the Jap-anese economy have contributed to the rapid increaseof FGD use. The Government provides low-interestloans and allows accelerated depreciation for facilitiesthat install control devices. The total investment in S02

control, including FGD and hydro desulfurization of oil,was about $3.7 billion in 1977 U.S. dollars.

Ambient S02 concentrations have declined substan-tially in major urban areas as a result of the abatementprogram. From a 1965 level of about 150 µg/m3, the1978 annual ambient average on a 24-hour basisdropped to about 40 µg/m3,21 a figure comparable tothe 1978 urban ambient average in the United States.

20’ ‘Envlronrnent in Japan 1981 ,‘ Envlronmenl Agen{ y, (hJ\ernnlent t)f]a-pan, December 1981

21wrltten ~ommunlcatlon ~lth s~.ill Ikkatal, Se{ t)ncl Se( retary, F.mbass} ~jf

Japan, Feb 23, 1983


D.3 MITIGATING THE EFFECTS OFACID DEPOSITION ON AQUATIC ECOSYSTEMS

Introduction

Available strategies for controlling acid deposition andits ecological consequences include both further control-ling pollutant emissions at their source and mitigatingeffects on sensitive resources—in particular, reducingthe acidity of sensitive lakes and streams. Ameliorativemeasures such as liming affected lakes, streams, and wa-tersheds have been proposed in several bills introducedduring the 97th and 98th Congresses. Research is alsounderway on developing acid-tolerant strains of fish andaquatic plant life.

Proposed emissions control strategies are likely to re-quire several years from enactment to implementation.

“ Likewise, biological experimentation to develop acid-re-sistant aquatic life will require many years. Thus, fewprospects exist for a short-term solution to the acid dep-osition problem. Alleviating the symptoms of the prob-lem—decreasing the acidity of soil or water and restor-ing normal buffering capacity by adding lime orlimestone— may save or restore many important recrea-tional and commercial fisheries while long-term solu-tions are developed and implemented.

Important biological or chemical effects of acid dep-osition on water quality or fish populations have beenreported in New York, Massachusetts, New Hampshire,Maine, Pennsylvania, West Virginia, North Carolina,and Tennessee, as well as in Ontario, Quebec, andNova Scotia. Almost all States and Provinces in theEastern United States and Canada are thought to con-tain some sensitive surface waters, based on analysesof their soils and geology.

The most sensitive lakes and streams generally arelocated in areas that receive high levels of acid deposi-tion, have steep topography, and are covered with thinand poorly buffered soils. If these soils are depleted oftheir limited capacity to neutralize incoming acidity,acid accumulates in lakes and streams within the wa-tershed, and, in turn, mobilizes toxic metals. Eventuallythe water body becomes unable to support its normalrange of plant and animal life. Temporarily restoringthe buffering capacity of a lake or stream by applyinglime or limestone can often allow aquatic life to berestored. For most mitigation efforts to date, the pri-mary objective has been to improve water quality suffi-ciently to maintain reproducing fisheries.

Liming has been effective in counteracting surface wa-ter acidification in parts of Scandinavia, Canada, andthe United States. Although its effects are only tempo-

rary, the material is inexpensive, the dosage requiredfairly well known, and the technology of applying limesimple.

However, not all lakes and streams respond suffi-ciently to liming to reestablish aquatic life. In particu-lar, lakes with rapid water flow in comparison to theirvolume (i. e., with water ‘ ‘retention time’ of less thana year), and running waters with great variation in flow,are very difficult to lime effectively. Moreover, it is im-possible to determine the effectiveness of a liming ap-plication without extensive monitoring of the chemicaland biological changes that follow. The results of indi-vidual applications will remain uncertain until more isknown about how liming affects various types of waterbodies. On the average, however, the buffering capacitythat a single application of lime restores to a lake orstream will be depleted over a period of 3 to 5 years,after which the effectiveness of the application must bereconsidered, and a decision made whether to continuemitigation efforts.

Possibly of greater concern with regard to establishinga wide-scale liming program is that scientists do notknow how periodic realterations of water body chemistrythrough liming will affect aquatic ecosystems over thelong term. For example, a number of substances thatnormally are found in a biologically inert form in neutralwaters become unbound, or soluble, in acidified waters.If, several years after liming, the lake again begins toacidify, accumulated metals that have been rendered in-soluble over a period of time may again become solu-ble and create a serious toxic condition. In addition, lit-tle is known about the effects of periodic or even singleapplications of liming on other living organisms in thewater body. While liming has enhanced fish survival ina number of lakes and streams, its long-term implica-tions for the food chain on which fish depend are un-certain.

Though it is neither possible nor desirable to lime allacid-sensitive aquatic ecosystems in the Eastern UnitedStates, liming can be an effective stopgap measure torestore or preserve water bodies of particular value fromthe effects of acid deposition. Some characteristics toconsider in choosing which water bodies to lime are:

●

●

●

the current or historic ability of the system to sup-port a viable and important fishery;recreational importance and public access to thewaters;present chemical condition, i.e., pH, alkalinity,acid loadings, watershed buffering capacity;

App. D—Exist ing Domest ic and Internat ional Approaches . 313

c physical factors— water retention time, geographiclocation; and

● economic constraints— costs of material, applica-tion, and frequency of reapplication.

Such characteristics must be assessed on a site-specificbasis before the feasibility of liming can be determined.Figure D-1 presents a series of criteria suggested by areport to U.S. Fish and Wildlife Service for evaluatingthe appropriateness of liming a water body. All of thesecriteria must be met for liming to be an appropriate mit-igating strategy.

Liming Materials

Many alkaline materials can be used to neutralizeacidified surface waters. These include lye, soda ash,olivine, and lime compounds, as well as several byprod-ucts and wastes of industries such as cement dust andsludge from water treatment plants. However, while in-dustrial byproducts are low in price, they frequentlyhave a high level of such impurities as heavy metals,which may exacerbate the already-elevated metal con-centrations typically present in acidified waters. Limecompounds are much more chemical] y uniform andhave been the neutralizing material of choice for the ma-jority of water bodies.

The term ‘ ‘lime’ is generally applied to several com-pounds of calcium and magnesium that are highly ca-pable of neutralizing acid. The three most often usedcalcium compounds are limestone (calcium carbonate),quicklime (calcium oxide), and hydrated or slaked lime(calcium hydroxide). Available magnesium-based com-pounds include dolomite, dolomite lime, and dolomitehydrated lime. Calcium lime is used more commonlythan dolomite. Dolomites have a slightly higher neu-tralizing value by weight than the nonmagnesium lime,but if their magnesium carbonate content is greater than10 percent, they may dissolve too slowly to be of valuein neutralizing acidified lakes and streams.

Crushed limestone, or “aglime, ’ is currently the pri-mary alkaline material used in experimental liming pro-grams in the United States and Canada and in morewide-scale programs in Scandinavia. The more acidicthe water, and the finer the limestone is ground, themore quickly it will dissolve. Limestone is a relativelyinexpensive natural material and is less caustic thanquicklime or hydrated lime. In general, limestone goesinto solution more slowly than either quicklime or hy-drated lime, but remains effective longer. The differ-ences between lime and limestone are shown in figureD-2.

Response to Liming

Chemical Changes

Adding a liming agent causes the pH of the waterbody to rise and restores alkalinity —i.e., the ability toneutralize further acid inputs. If a very soluble base suchas quicklime is added, pH rises sharply, and the highestpH is reached shortly after the treatment. In a New YorkState lake, for example, adding lime initially raised pHfrom 5 to 9—a ten-thousandfold decrease in acidity be-fore the water body reached equilibrium at a lower pHvalue. The shock from such chemical changes, if toorapid, can be lethal to a variety of aquatic life, espe-cially fish. When a less soluble agent such as limestoneis added to a water body, the rise in pH is less dramatic.The pH generally will not exceed 7, even during theinitial period after limestone is added. Applied as apowder or finely crushed stone, it will settle readily tothe bottom and dissolve slowly.

Aluminum, manganese, and zinc frequently arefound in elevated concentrations in acidified waters.High levels of copper, mercury, nickel, and iron mayalso be present due to leaching from surrounding soilsor industrial wastes. These trace-metal concentrationsgenerally decrease after acidified waters are limed. Afterexperimental liming at four lakes near Sudbury, On-tario, decreases in metal concentrations ranged from 66to 91 percent for aluminum, 23 to 73 percent for zinc,15 to 79 percent for manganese, 32 to 95 percent forcopper, 23 to 81 percent for nickel, and 15 to 89 per-cent for iron. Such metals will precipitate out of solu-tion most quickly in small shallow lakes where limingagents mix thoroughly in a short time .22 Dissolvedorganic material, which usually gives water a brownishtint, also will be removed as the metals precipitate outof solution. This causes the water to appear more trans-parent following liming. *

The chief agent responsible for fish mortality in acid-ified water bodies is aluminum released by acid perco-lating through watershed soils. Although aluminum isthe most prevalent metal in the Earth’s crust, the con-centrations of soluble aluminum compounds are low insurface waters with moderate acidity levels (above pH5.5). As surface-water pH drops to about 5, aluminum

“J. E. Fraser and D L Britt, Liming of AcidIfied }$’arcrs A Retmw of,Methods and Effects on Aquatic Ecos,vstems, L’ S Fish and Wddilfe Service,Diwsion of Biological Services, Eastern Energy and Land Use Team, FWS/OBS80/40. 13, 1982

“Acidlficatirm of water bodies also mav make them clearer as phytoplankton(tiny plan[ life) die off


Figure D-1.— Criteria for Evaluating a Water Body for Suitability of Liming

Yes

App. D—Existing Domestic and International Approaches ● 315

Figure D-2.—Comparison of Lime and Limestone

Lime I Limestone (CaC03) I

becomes much more soluble and more toxic to fish. Be-low pH 4.5, aluminum appears to have less effect onfish, but acidity levels themselves are so high that fewspecies can survive. If a water body of less than pH 5is limed, it will pass again through the critical pH rangeat which aluminum is especially toxic—and for a brieftime fish mortality will be of concern. As the pH in-creases beyond this range, the aluminum will precipitateout of solution and settle to the bottom.

The pH of surface waters will gradually decrease ifsignificant acidic inputs continue from precipitation,streamflow, ground water infiltration, or perhaps evenfrom the lake sediments as they use up the buffering ca-pacity of the water above them. Liming will generallyprevent acidity from increasing for about 3 to 5 years.However, once acidity increases again, aluminum andother soluble metals that have been precipitated out ofthe water are again ‘ ‘mobilized. The water may con-tain greater concentrations of metals following reacidi-fication than in its original acidified state several years

earlier. This is because the sediments will release boththose metals initially precipitated out of solution by add-ing lime as well as those that entered the lake or streamand settled to the bottom while the lime provided buf-fering capacity. Continued liming must be timed care-fully to prevent such toxicity from recurring. Table D-1 displays water quality changes in an acidified Ontariolake immediately prior to, and for 6 years following, theaddition of lime.

Biological Changes

Acidification of aquatic ecosystems reduces the diver-sity of the normally present biological community. Thetotal number of plant and animal species often decreasessignificantly. Species sensitive to acidic conditions areeliminated while tolerant species proliferate. Acidifica-tion inhibits the bacteria normally responsible for de-composition, thereby slowing the rate of nutrient cy -

Table D-1 .—Changes in Chemistry of Lohi Lake, Ontario, Canada, FollowingAddition of Neutralizing Agents in 1973 (hydrated lime), 1974 (hydrated lime and limestone)

Parameters 1973 1974 1975 1976 1977 1978 1979

pH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.39 6.04 6.09 6.09 5.27 4.79 4.76Copper (mg/m3) . . . . . . . . . . . . . . . . . , , , 84 44 43 37 44 71 —Aluminum (mg/m3). . . . . . . . . . . . . . . . . . — 140 110 120 100 160 —Water transparency (Secchi disk, m) . . 8.8 5.6 5.7 5.7 6.9 9.3 7.6Alkalinity µeq/l) . . . . . . . . . . . . . . . . . . . . O 46 102 44 0 0 0SOURCE: National Research Council Canada, “Acidification in the Canadian Aquatic Environment: Scientific Criteria for Assess-

ing the Effects of Acidic Deposition on Aquatic Ecosystems, ” Ottawa, Canadian Environmental Secretariat, 1981,


cling. Aluminum toxicity associated with acidificationeliminates various fish species.

Liming drastically decreases the density of acid-tol-erant phytoplankton (e. g., algae). Normal populationsgenerally will be established within about a year. Nor-mal zooplankton populations (animals that feed on thephytoplankton) may take much longer to recover. Fishpopulations, in turn, feed on the zooplankton; thus, sev-eral years may be required to reestablish a viable fish-ery. Liming experiments so far have shown enhancedsurvival of natural populations of brook trout in Adiron-dack lakes; lake trout, brook trout, and smallmouth bassin an Ontario lake; and Atlantic salmon in a Nova Scotiastream.

Biological diversity in limed water bodies might beenhanced by adding organic carbon and/or phosphorusin nutrients (organic humus or perhaps biologicallytreated wastewater). Phosphorus, an important elementin phytoplankton nutrition, is often in short supply inacidic waters. Limited success has been reported whenphosphorus was added following liming in Canadianlakes. The effect of adding organic carbon is highly spec-ulative. If these nutrient additions prove effective inenhancing recover-y of limed acidified water bodies, theycould be applied at little cost.

Costs and Methods of ApplyingLiming Materials23

The techniques available for liming aquatic systemsdepend on the type of neutralizing material used, theavailability of dispersal equipment, and the target areabeing limed. The major application methods used todate in the United States, Canada, and Scandinavia areoutlined in figure D-3.

The accessibility of the water body may determinethe appropriate liming method. For example, a remotelake can be limed only by aircraft, while an accessiblewater body can be limed by truck or boat. Directly lim-ing the water body appears to be the most economicallyefficient technique. It is currently the most commonlyused method for lakes, and is appropriate as long as thewater retention time (a measure of how rapidly the lakeis replenished) is longer than 1 year. If the water reten-tion time is short, the added alkalinity will quickly leavethe system (although it may neutralize water bodiesdownstream). Liming tributary streams might providedownstream lakes and rivers with longer term buffer-ing capacity, and enhance fish spawning.

Researchers have yet to determine whether acidifiedaquatic resources may be restored more effectively byliming watersheds or lakes and streams themselves.—-

zs”rhl~ ~cctlon IS based In part on Fraser and Britt, op. cit. , 1982.

However, to achieve comparable acid-neutralizing ca-pacities in surface water, 100 times more lime must beapplied to a watershed than directly to a water body.Despite this, Sweden has applied 40 percent of its totaltonnage of lime on land.

For maximum effect, lime should be added shortlybefore critical periods of peak acidity and biological ac-tivity, i.e., during early spring, for surface waters thatstill support fish populations. Spring snowmelts oftenflow directly into water bodies without experiencing thepotential neutralizing effects of soils. In much of theEastern United States and Canada, this snowmelt hasa pH of less than 4.5. The acidity that has been storedin snows throughout the winter reaches water bodieswhen sensitive embryos and fish fry are developing. Al-ternatively, liming lakes slightly later in the season, dur-ing the spring overturn, takes advantage of lake circula-tion patterns to enhance mixing and distribution ofneutralizing agents.

Table D-2 outlines costs of limestone materials, trans-port, and application in Sweden in 1981. Normally, 1to 2 tons of limestone are added per acre of surface wa-ter. The Government of Sweden has undertaken themost extensive liming program to date—3,000 lakes,3,000 kilometers of streams, and 500 watersheds fromthe program’s inception through July 1983. Total pro-gram costs have reached $17 million to date, includingapproximately $4 million to lime 500 lakes in fiscal year1983.

Several waterway deacidification experiments havetaken place in North America. Since 1973, the OntarioMinistry of the Environment has limed four acidifiedlakes in the Sudbury region. The treatments have beensuccessful in returning pH to normal levels.

The most extensive program in the United States wasbegun by the New York State Department of Environ-mental Conservation in 1959. It initially targeted small,naturally acidic ponds in heavily used recreational areas,and expanded to treating selected acidified lakes withsignificant potential to support recreational fishing dur-ing the mid-1970’s. The program is quite small in scope;only about 60 lakes in total (covering approximately1,000 acres) have been treated to date. It has signifi-cantly improved water quality at a number of lakes andponds, and permitted self-propagating sport fishing pop-ulations to be maintained and/or reintroduced. Costsfor liming ponds and lakes under the program haveranged from approximately $50 to $300/acre for eachapplication, depending on the size and accessibility ofthe water body. Between 1 and 2.2 tons of lime are nor-mally added per acre of surface water to be treated—costs for transporting the material to the lake site con-stitute a significant portion of overall expenses.

Currently, only Massachusetts and New York haveformal surface water mitigation projects. Since 1957,

App. D—Exist ing Domest ic and Internat ional Approaches ● 3 1 7

Technique

Boats

SedimentInjecti on

Figure D-3.—General Comparison of the Various Liming Application Techniques

Table D-2.—Range of Costs for Limestone Materials,Transport, and Application in Sweden 1981

Liming parameters costs

Materials:Bulk limestone . . . . . . . . . . . . . . . . . . . . . . . . $20-$30/tonBagged limestone . . . . . . . . . . . . . . . . . . . . . $40/ton

Transport of limestone . . . . . . . . . . . . . . . . . . . $10-$20/tonApplication techniques:

Truck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . $4-$6/tonPontoon boat with blower . . . . . . . . . . . . . . $10-$ 16/tonHelicopter . . . . . . . . . . . . . . . . . . . . . . . . . . . . $30-$40/tonBy hand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . $20-$60/ton

SOURCE National Fisheries Board of Sweden, Rad och Riktinijer for Kalkningav Sjoar OCh Vattendrag, Report No. 1, 1982

Massachusetts has limed about 40 small ponds cover-ing 2,000 acres. Funded for liming is quite limited, how-ever, and future projects are uncertain. New York hasdeveloped a 6-year liming plan. During this time, 33lakes will receive aglime treatments, and extensive chemi-cal and biological monitoring will be conducted. A re-cent study of liming requirements in the Adirondack re-gion of New York estimated that a 5-year program forliming all the known acidified lakes in the region wouldcost from $2 to $4 million per year, depending on thetargeted buffering level .24 This estimate represents

14F ~ ~~~nz ~nd C. T Drisc 0 1 1 , “An Estmate of the (;OSIS of Limlrrg [oN“eutrallze ,ACICIIC ,Acliron(fa( k Surfa( e i$raters, ( ontrlhutmn # 1 ‘f. Upstate

~“reshwdter [nstltutc, June 1983


materials and labor only; it does not include costs forfish restocking or continued monitoring which can beconsiderable. Particularly in the initial stages of a lim-ing program, frequent monitoring for chemical and bio-logical changes in treated water bodies is necessary. An-nual costs may range from $3,000 to $20,000 per lake.When a sufficient data base exists to develop a generictreatment protocol for various aquatic ecosystems—water bodies of differing geological, chemical, and bio-logical characteristics—monitoring costs may be reducedsignificantly.

No direct Federal support is currently being providedto States, localities, or other organizations that under-take to treat acidified surface waters. Federal involve-ment in mitigation research began in 1982 under thedirection of the Fish and Wildlife Service (FWS), as pro-vided for in the National Acid Precipitation AssessmentPlan. * To date, the Federal research effort has produceda technical report on liming25 and an agenda of further

“~;hapter 6 discusses the National Acid Precipitation Assessment Programand Federal research on mitigation techniques in greater detail

Z~Fraser and Britt, 1982.

research needs determined by participants in an inter-national mitigation conference. Current plans for fieldresearch include monitoring the effects of liming on fishpopulations in several lakes in the Adirondack Moun-tains, as part of the research program on water chem-istry sponsored privately by the Electric Power ResearchInstitute. FWS is also supporting a pilot scale limingproject on 10 acidified lakes in the Adirondack regionin an attempt to understand the variation in responseof fish populations and to evaluate the success of restock-ing strategies. Total Federal funding for such efforts infiscal year 1983 amounted to about $225,000. The ad-ministration recently proposed about $.5 million for lim-ing research for fiscal year 1985. Such funding increaseswould permit researchers to study the effects of limingon water bodies with differing geological, chemical, andbiological characteristics throughout the Eastern UnitedStates, and to investigate the effectiveness of alternativemitigation measures.

Index

a( id deposition, 3, 5, 9, 10, 11, 12, 13, 15, 16, 27, 28,42, 49, 80, 81, 85, 87, 106-110, 124, 212

Adirondacks, .5, 13, 44, 81, 82, 112, 213, 230,Ad\anced Statistical ‘1’rajectory Regional Air Pollution

Model (ASTRAP), 280agricultural prmductivit), ad~’erse effects, 12, 90, 217Air Qualit) (;ontrol Reqions (AQRs), 136Alabama, 63, 85, 90, 98, 125, 126.4ppala[ h ians, 50, 51, 85, WI, 127, 141, 196, 226Arkansas, 52, 90atmospheric processes, 265-299

chemistry, 26.5-273altering emissions of primary pollutants, 269deposition of sulfur and nitrogen, 265oxides of nitrogen, 267oxides of sulfur. 266ozone, 268

source-receptor rclatiortships, 274-299acid-producing substances, 274t ont ribut ions to acidic deposition, 279cffecti~encss of cmissions reductions for achieving

deposition reductions, 286rclat ionsh ip between current emissions and

deposit ion, 279‘ ‘target cieposition rates, 289

13rookha\en National I.aboratory, 255Business Roundtablc, 29

Canada, 3, 5, 13, 29, 30, 31, 43, 47, 48, 119, 120, 125,

213, 302-305, 307Center for Air Pollution Impact and Trend Analysis, 253Con$ress:

House Committee on Energy and Commerce, 27Senate Cotnmittec on Environment and Public Wrorks,

27cf)n,grcssiona] interest, 41-48, 80-90, 105-120, 123, 146Connecticut, 52(;ounci] on Environmental Quality (CEQJ, 117domestic and international approaches, 300-318

Clean Air Act, 300control of transboundar> pollution, U. S .-Canada,

302-305intc’rstatc pollution control and the Clean Air Act,

300international programs, 305

Canada, 307Denmark, 310Europe”, 30.5, 306, 307Japan, 311Norwa}r, 309Sweden, 308Uni[cd Kingdom, 310\Vest Germany, 310

mitigating the effects of ac id deposition on aquaticresources, 312

liming materials, 313-318

Index——._——

Edison Electric Institute. 192effects of transported pollutants, 207-264

aquatic rtsourrcs, 207-216effects of acid deposition, 212

economic sectors, 261health risks, 255-261

acid precipitation, 259nitrogen oxides, 258

materials, 239-244terrestrial resources, 217

agricultural product i~’it?’, 217effects of acid deposition, 228effects of acid rain, 218effkcts of multiple pollu tan ts on forests, 224effects of ozone on forest product itit}r, 227

\’isibilit)’, 244factors affecting, 244-248key studies, 253measurement techniques, 252mechanisms of degradation, 248

Electric Power Research Institute, 279emissions, 57-63, 106-111, 149-206

control technologies 153-167n itrogcn oxides, 166-167

flue-gas treatment, 167sulfur dioxide, 157

cost

coal clean ing, 158dr) processes of FGD, 165flue-gas desulfurization, 164fluidized bed combustion, 164fuel-switching, 157limestone injection multistage burner (LIMB), 16:3oil desulfurization, 163regenerable processes, 166wet scrubbers, 164of control, 149, 167-180

o~erview of model used in cost analyses, 178state-b?’-state reductions, 170-178

current and historical, 57, 58future, 59

hydrocarbon, 61nitrogen oxides, 59sulfur dioxide, 59utility sulfur dioxide, 61, 62

industrial and commercial boilers, 183industrial processes, 183-185mobile sources, 185trends in highway \’chicle emissions, 187legislating, 123-146secondary economic effects of programs, 190-206

coal production and related employment, 190employment forecasts, 194methods of’ projecting production, 192patterns of change, 195reser~.es and current production, 190

elect ricity-intcnsi~’c industries, 199-201utilities in the eastern 31 states, 201-206

321


state regulatory policies, 203tax strategies, 180-182

Energy & Resource Consultants, Inc., 183European Economic Community (EEC), 306

Federal Aviation Administration, 244Federal concern, 29Florida, 49, 52, 126Ford, 189forest productivity, 12, 89

General Electric, 163General Motors, 189geographical patterns of deposition and air concentrations

for transformed pollutants, 63Georgia, 63, 83, 85, 125, 126Great Smoky Mountain National Park, 213

Harvard School of Public Health, 256

ICF, Inc., 192, 193Illinois, 12, 49-50, 82, 90, 142, 195, 242Indiana, 12, 49, 50, 64, 82, 90, 142Interagency Task Force, 105, 114, 118interstate coal shipment, 142Iowa, 82, 90

Kentucky, 46, 49, 50, 81, 82, 98, 142, 190, 195

legislating emissions reductions, 123, 146By what time should reductions be required?, 130How should emissions reductions be allocated?, 133How widespread should a control program be?, 125-126What approach to control should be adopted?, 131What can be done to mitigate employment and

economic effects of a control policy?, 140What level of pollution control should be required?, 126Which pollutants should be further controlled?, 123-125Who should pay the costs of emissions reductions?, 138

legislation:Acid Precipitation Act of 1980, 21, 23, 105, 114, 115,

117, 118Airline Deregulation Act of 1978, 143Clean Air Act, 3, 5, 15, 23, 24, 27, 29, 35, 36, 48, 59,

105, 106, 109, 118, 1 ~9, 120, 132, 139, 141, 142,145, 189, 199, 244, 255, 300, 301, 302, 308

Dingell-Johnson Act, 112, 13, 114Economic Recovery Tax Ac of 1981, 144, 145Trade Act of 1974, 143

liming lakes and streams, 19, 1 ~, 111-114Limestone Injection Multistage , ~rners (LIMB), 144Louisiana, 126

Maine, 52, 82, 90, 119Memorandum of Intent, 48, 119Michigan, 52, 142Minnesota, 48, 82, 209Mississippi, 63, 90, 107, 125, 126Missouri, 49, 90, 126, 142

National Academy of Sciences, 29, 53, 117, 289National Acid Precipitation Assessment Program

(NAPAP), 21, 23, 108, 115, 116, 117, 207National Ambient Air Quality Standards (NAAQS), 23,

24, 105, 118, 119, 120, 131, 132, 133, 268, 300National Clean Air Coalition, 192National Commission on Air Quality, 28National Crop Loss Assessment Network (NCLAN), 217National Governors’ Association, 28National Wildlife Federation, 192New England, 5, 12, 13, 48, 53, 80, 83, 125, 127, 224,

231New Hampshire, 82, 90, 114New Jersey, 44, 81New Source Performance Standards, 61, 129, 131, 195New York, 48, 82, 112, 119, 125, 183, 214, 231, 242New York State Department of Environmental

Conservation, 112, 113North Carolina, 17, 64, 81, 82, 90, 107, 126Norway, 82, 230Nova Scotia, 82, 214

Oak Ridge National Laboratory, 208, 230Ohio, 5, 12, 49, 50, 63, 82, 111, 143, 195Ontario, Canada, 82, 125, 213, 214Ozark Mountains, 85ozone, 4, 7, 11, 12, 13, 27, 33, 34, 85, 86, 227, 228, 268

Pennsylvania, 5, 49, 50, 52, 63, 82, 98, 111, 114, 119,127, 183, 278

policy debate, characteristics of, 30-31policy options, 15-24, 105-120

current law and recent proposals, 105liming lakes and streams, 18, 106, 111-114mandatory emissions reductions, 16, 106-111modifying existing provisions of the Clean Air Act, 23,

106, 118-120modifying the current research program (NAPAP) to

provide mom timely guidance to Congress, 21modifying the Federal acid deposition research

program, 115-118pollutants of concern, 4-9, 57-75

hydrocarbons, 4, 27, 57-75, 123-146nitrogen oxides, 4, 5, 7, 8, 12, 27, 49, 57-75, 93, 95,

105, 106, 123, 146, 149-167sulfur dioxide, 4, 5, 7, 8, 9, 12, 15, 16, 27, 49, 57-75,

92, 95, 96, 97, 105, 107, 123-146, 149-180precipitation acidity (pH), 5, 6, 9, 42, 125, 126, 213,

224, 225, 266public concerns, 28

Redwoods National Park, 143regional distribution of risks, 79-101

aquatic ecosystems, 80health effects, 94materials, 91rates of pollutant emissions, 94shifts in coal production, 97-101terrestrial ecosystems, 82

.

Index ● 3 2 3

utility industry, 95visibility, 91

risk and uncertainty, 31-32regional patterns of sulfur oxides transport, 64-75

San Bernardino Mountain Study, 228scientific uncertainties, 32-37

current damages, 32effectiveness of reducing emissions, 36future damages, 33origin of observed levels of transported pollutants, 34research program, 36

State Implementation Plans (SIP), 61, 118, 120, 167, 178,301

Stockholm Conference on the Acidification of theEnvironment, 1982, 29, 53

South Carolina, 64, 85Sweden, 82

Tennessee, 12, 17, 44, 49, 50, 81, 107, 126Tennessee Valley Authority (TVA), 164, ~65The Institute of Ecology (TIE), 207, 209transported air pollutants, 41-54

effects on utility and industrial financial health, 51effects on U.S. coal market, 50resources at risk, 41

aquatic ecosystems, 41terrestrial ecosystems, 43

risks of health effects, 47risk of strained international relations, 48utility control costs, 49

United Mine Workers, 142, 198, 199University of Illinois, 256U.S.-Canada Memorandum of Intent on Transboundarv

U s .U s .U s .U s .Us.

U s .Us.Us.

Air Pollution, 53, 120, 149, 181, 242, 279, 289Census Bureau, 199Chamber of Commerce, 29Department of Agriculture (USDA), 218Department of Energy, 29, 149, 161, 183, 192Environmental Protection Agency (EPA), 18, 19,23, 24, 29, 35, 46, 48, 105, 106, 108, 110, 117,118, 119, 120, 126, 128, 129, 131, 143, 144, 149,161, 178, 185, 189, 192, 217, 259, 300, 301

Fish and Wildlife Service (FWS), 113, 114Forest Service, 85Geological Surve), 208

Vermont, 12, 44, 4!3, 52, 82, 90, 114Virginia, 44, 47, 52, 81, 98

West Germany, 44, 118, 230West Virginia, 5, 49, 56, 63, 81, 82, 98, 127, 143, 161,

190, 195, 278Wisconsin, 48, 82

0