DOE - Chemtrails - Tropospheric Aerosol Program

8/10/2019 DOE - Chemtrails - Tropospheric Aerosol Program

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DOE/SC-0034

Tropospheric

Aerosol

ProgramRG99 060050.3

Program Plan

March 2001

U. S. Department of EnergyOffice of ScienceOffice of Biological and Environmental ResearchEnvironmental Sciences Division


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DISCLAIMER

This report was prepared as an account of work sponsored by an agency of the UnitedStates Government. Neither the United States Government nor any agency thereof, norany employees, nor any of their contractors, subcontractors or their employees, makes

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Printed on recycled paper


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ForewordThe Department of Energy (DOE) and itspredecessor agencies, the Atomic Energy

Commission and the Energy Research andDevelopment Administration, have a long andenviable record of accomplishment in thescience of atmospheric aerosols. Thisresearch, which had its genesis in the study offall-out from atmospheric weapons testing, hasfound valuable new application in under-standing the environmental effects of fossilfuel combustion and allied energy-relatedactivities.

Now, consistent with the Nation's desire topreserve and enhance our environment andminimize the risk to human health and welfare

from atmospheric pollutants, the atmosphericscience research community faces a newchallenge to develop sensible and effectivestrategies to achieve the new NationalAmbient Air Quality Standard for fine particles,the so-called PM-2.5 standard. Achieving thisstandard in a way that will have minimumimpact on the Nation's ability to meet itsenergy requirements requires a much morecomplete understanding of the processesgoverning the loading, composition, andmicrophysical properties of these aerosolsthan is now available.

Fine particles are implicated in anotherimportant issue that may affect the Nation'senergy economy, namely climate change.Fine particles scatter solar radiation,decreasing the amount of the sun's energythat is absorbed by the planet and therebyexerting a cooling influence on climate. Themagnitude of this influence is not known forcertain, but recent estimates indicate that it iscomparable to the warming influence ofincreased concentrations of greenhouse gasesand may consequently be offsetting a majorfraction of the greenhouse warming that wouldotherwise have been experienced over theindustrial period. Because aerosols are short-lived in the atmosphere this effect cannot be

considered a mechanism for forestalling thegreenhouse effect. But to understand climatechange it is necessary to obtain accurateestimates of the totality of climate influencesover the industrial period, and in particular theaerosol influences.

The Tropospheric Aerosol Program (TAP)described in this Program Plan will makecrucially-needed contributions to improvedunderstanding and model-based description ofthe loading and properties of atmosphericaerosols in relation to sources, pertinent toboth of these major environmental issues.Scientists from the DOE National Laboratorycommunity together with colleagues from theacademic community, the private sector, andother governmental agencies responsible forunderstanding and maintaining ouratmospheric environment have contributedsubstantially to the preparation of this Plan.

The talent required to understand and resolvethese important national issues lies collectivelywithin and beyond the Department of Energy.Thus we view TAP as a component of alarger, informal national aerosol program,where TAP both contributes to and leverages

other aerosol research efforts. Indeed, TAP isdesigned to fill some very important gaps andcomplements existing programs. We lookforward to working closely with our partnerswithin DOE and in other state and federalagencies, industry, and academia.

With this cooperative effort TAP will serve theobjectives of these communities and therebymake a major contribution to meeting thegoals of the Air Quality Research Sub-committee of the Committee on Environmentand Natural Resources, while at the same time

supporting the DOE mission of fostering aNational Energy Strategy that takes intoaccount the preservation and enhancement ofthe Nation's atmospheric environment.

Dr. Ari PatrinosAssociate Director for Biological and

Environmental ResearchOffice of ScienceU. S. Department of Energy


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v

Executive SummaryAir quality in the United States has improved

substantially over the past three decades as aresult of the Clean Air Act and itsamendments. However, a few majorunresolved issues remain in accomplishingthe task of minimizing the publics risk to airpollution exposure. Key among these is therelation of adverse health effects to exposureto airborne particles, or aerosols.

The significance of the environmental stress ofparticulate air pollution and the mechanisms ofits action on humans remain unresolveddespite years of research. Historically,attention has shifted from crude measures ofexposure represented by the massconcentration of total suspended particles tomore refined measures that segregate massconcentration by the upper limit particle size,initially 10 m and more recently 2.5 m.However it is not established that it is themass concentration of particulate matter that isin fact responsible for its health effects. Asknowledge has evolved and measurementmethods have improved, health scientistshave begun to turn their attention to the

chemical components present in particles.This has led to the recognition that availablemeans of determining chemical properties maybe limiting the identification of components inparticles responsible for their influence onhuman health.

In addition to their influence on health, fineparticles affect public welfare in otherimportant ways. These particles scatter andabsorb light, leading to impairment of visibilityand to a potential influence on climate changethat must be quantified to understand the full

implications of increasing concentrations ofgreenhouse gases. Light scattering andabsorption by fine particles also affect surfaceirradiance, with a potential resultant influenceon plant growth and length of the growingseason. Deposition of fine particles and theirprecursors to the surface affects the chemicalbalance of ecosystems, not just by so-called"acid deposition" but also by alteration ofnutrient balance. For these reasons also

quantitative understanding is required of the

processes that control the atmosphericloading, composition, and microphysicalproperties of fine particles, together with thecapability to represent these processes inatmospheric chemical transport models.

In 1997, the U.S. government made acommitment to reduce fine particles in the airby modifying the National Ambient Air QualityStandards (NAAQS) by establishing a newstandard for fine particulate matter, the PM2.5standard. The public debates that took placein developing this standard revealed thatscientific information supporting this nationalobjective continues to have unacceptably highlevels of uncertainty. As a result, the nationhas embarked on a substantial new programof research to reduce these uncertainties.Initial attention has focused mainly on two ofthe technical issues necessary to reduce thisuncertainty: characterizing human healtheffects due to exposure to fine particles anddetermining the nature and extent of fineparticle exposure across the United States, asspecified by the new NAAQS.

While the above two elements are key todefining the root cause of the health effectsand to identifying the geographic locations ofnon-attainment, they will fall short of leading toan efficient approach to controlling theproblem. To achieve this goal the newnational program needs two more elements: agreatly improved system for quantitativelycharacterizing emissions, and greatlyimproved understanding of the basic physico-chemical processes responsible for theformation of particles and evolution of their

properties in the atmosphere. Without theseelements it will not be possible to link emissionreductions with reductions in particleconcentrations and thereby formulate arational and efficient strategy to achieve thePM2.5 standard. Absence of this knowledgealso precludes developing strategies thatwould be targeted to specific substances infine particulate matter that might achieve realbenefits to human health.


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TAP Program Plan

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The uncertainties in specifying emissions andatmospheric processes linking sources andatmospheric concentrations are as numerousand complex as those linking health effects toexposures. Thus, a substantial investment inprocess focused research is needed fordecision-makers to ensure that the bestinformation is available to construct newstrategies for minimizing the health andenvironmental consequences of exposure tofine particles resulting from energy productionor use. Improved emissions inventories arenow being developed by the air pollutionresearch community under support from avariety of sources. However the study of theatmospheric processes that govern theevolution of mass loading and chemical andphysical properties of aerosols remains a

weak link in the chain.

The Department of Energys TroposphericAerosol Program (TAP) will, in collaborationwith research by NOAA, EPA, and otherFederal and state agencies, address the fourthcritical element, the atmospheric science offine particles. TAP falls within the purview ofthe Department of Energy for a number ofreasons. Fine particles in the atmospherederive largely from energy production and use;DOE has a statutory responsibility to conductresearch into the health and environmental

consequences of these activities. Moreover,any control measures that are proposed willlikely have considerable impacts on energyproduction and consumption technologies andenergy costs. DOE also has a long history of

distinguished research in atmosphericaerosols, photochemistry, and meteorologyand as a consequence has the requisite poolof talent to examine these complicatedprocesses in detail.

The goal of TAP will be to develop thefundamental scientific understanding requiredto construct tools for simulating the life cycle oftropospheric aerosols--the processescontrolling their mass loading, composition,and microphysical properties, all as a functionof time, location, and altitude. The TAPapproach to achieving this goal will be byconducting closely linked field, modeling,laboratory, and theoretical studies focused onthe processes controlling formation, growth,transport, and deposition of tropospheric

aerosols. This understanding will berepresented in models suitable for describingthese processes on a variety of geographicalscales; evaluation of these models will be akey component of TAP field activities. Incarrying out these tasks TAP will work closelywith other programs in DOE and in otherFederal and state agencies, and with theprivate sector. A forum to directly work withour counterparts in industry to ensure that theresults of this research are translated intoproducts that are useful to that community willbe provided by NARSTO (formerly the North

American Research Strategy on TroposphericOzone), a public/private partnership, whosemembership spans government, the utilities,industry, and university researchers in Mexico,the United States, and Canada.


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ContentsForeword ...................................................................................................................................iii

Executive Summary ................................................................................................................. v

1. Introduction ..............................................................................................................................1

1.1 Tropospheric Aerosols and Their Importance ...................................................................1

1.2 Priority Components of TAP .............................................................................................3

1.3 Benefits to be Derived from TAP........................................................................................5

1.4 Consequences of Not Doing this Research ....................................................................... 5

2. Overview and Background ......................................................................................................7

2.1 The TAP Initiative...............................................................................................................7

2.2 Fine Atmospheric Particles ................................................................................................7

2.3 The DOE Context............................................................................................................. 12

2.4 The Science Context for TAP........................................................................................... 13

2.5 The TAP Approach .......................................................................................................... 15

3. The TAP Objectives ................................................................................................................ 173.1 What TAP will Accomplish ............................................................................................... 17

3.2 TAP Research Tasks and Scientific Issues ..................................................................... 17

4. Organizational Structure .......................................................................................................19

4.1 Organizational Elements of TAP ...................................................................................... 19

4.2 Science Team .................................................................................................................. 20

4.3 Science Support Team .................................................................................................... 20

4.4 Integration ........................................................................................................................ 20

4.5 Oversight and Interagency Coordination ......................................................................... 21

4.6 Relation to Other DOE Programs.....................................................................................21

4.7 Relation to Other Federal Programs................................................................................ 23

5. Science Implementation ........................................................................................................ 25

5.1 Field Measurements ........................................................................................................255.2 Instrument Development and Advanced Characterization............................................... 35

5.3 Modeling .......................................................................................................................... 41

5.4 Laboratory Studies and Theory........................................................................................ 45

6. Science Support Implementation ......................................................................................... 51

6.1 Support for Field Studies ................................................................................................. 51

6.2 Data System and Archive ................................................................................................ 55

6.3 Support for Modeling Activities ........................................................................................ 56

6.4 Scientific Communication................................................................................................. 57

7. Deployment Schedule and Resource Requirements ..........................................................59

7.1 TAP Science Team .......................................................................................................... 60

7.2 TAP Science Support Team ............................................................................................ 61

7.3 TAP Project Support ........................................................................................................617.4 Capital Items .................................................................................................................... 61

References ..............................................................................................................................67

Appendices ............................................................................................................................. 67

Appendix A Workshop Participants ......................................................................................... 73

Appendix B Instrumentation and Characterization Techniques Available for Use in TAP........ 77

Appendix C Relationship Between TAP and Other Federally Funded PM Research Programs.... 85

Appendix D Acronyms.............................................................................................................. 89


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1. Introduction

1.1 TroposphericAerosols andTheir ImportanceThere is a compelling body of evidencethat increasing concentrations oftropospheric aerosols from humanactivities are potentially major factors in

human health and welfare.

Tropospheric aerosols are suspensions of fineparticles, of diameter ranging fromnanometers to micrometers, in the lower fewkilometers of the atmosphere. Thesesuspensions derive from primary sourcesinvolving direct emissions of particles, and bysecondary processes, reactions of gaseousprecursor emissions in the atmosphere to formparticulate matter.

Fine airborne particles have been associated

with adverse influence on human health innumerous studies. Much of the relevantresearch is summarized in the 1999 Draft EPACriteria Document for Particulate Matter (EPA,1999a), which identifies the following effects:(1) lung function decrements; (2) respiratorysymptoms, or exacerbation of symptomsrequiring bronchodilator therapy; (3) hospitaladmissions for respiratory and cardiovascularcauses; (4) emergency medical visits; and (5)death largely from cardiopulmonary causes inthe elderly. {pp 8-33 - 8-34]. The documentpresents a detailed examination of healtheffects associated with ambient particulatematter, examining the results of severalstudies that attempted to quantitativelydetermine the relative risk associated with agiven concentration of PM. That examinationconcluded that "All of these long-term studiesreport many statistically significant findingsassociated with long-term mean PMconcentrations. " [page 8-32]. However there

remain important unresolved questions aboutthe mechanism of insult, and whether theinsult depends solely on the massconcentration of particles or on their chemicalconstituents.

Aerosol particles are also responsible forvisibility impairment not just in urban areasand multi-city complexes, but also overwidespread areas that encompass NationalParks and wilderness areas for which it isdesired to protect and enhance air qualityrelated values. Aerosol particles and theirprecursors are the carriers of a number ofhazardous air pollutants, and are the chemicalagents responsible for acid deposition. Theyare also recognized to exert a major influenceon the shortwave radiation energy budget ofthe Earth, and in the aggregate anthropogenicaerosols may be offsetting a major butunknown fraction of the anthropogenicgreenhouse effect.Of these several issues, the issue of aerosolinfluences on human health is viewed ashaving the highest priority in setting research

directions and priorities.

Evidence suggesting adverse consequencesfor human health of airborne particles has ledto the establishment of a series of NationalAmbient Air Quality Standards (NAAQS)designed to reduce the risks of breathingpolluted air. The most recent NAAQSestablished in 1997 has objectives for cleanair based on fine particle mass concentration.The controversy surrounding the scientificbasis for this standard has resulted inCongressional direction to re-examine and

elaborate on this scientific information.Atmospheric processes are central to this re-examination because of their critical role indetermining aerosol properties governing theirhealth effects.

In response to this direction, agencies of thegovernment have initiated a national programto investigate the origins, evolution and healthconsequences of fine particles and their

Fine airborne

particles are

associated

with

respiratorydisease,

visibility

reduction,

acid

deposition,

and climate

change. Of

these issues,

the issue of

aerosol

influences on

human health

assumes the

highest

priority for

setting

researchdirections.


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TAP Program Plan

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chemical constituents. Much of the impetusfor the direction of fine particle research lieswith the Committee on Research Priorities forAirborne Particulate Matter of the NationalResearch Council (NRC, 1998; 1999; 2001).

This enterprise is coordinated by the FederalInteragency Air Quali ty ResearchSubcommittee (AQRS), and much of theresearch is implemented in collaboration withNARSTO (formerly North American ResearchStrategy for Tropospheric Ozone, but nowsimply NARSTO, in recognition of itsexpanded effort directed to particulate matter;see NARSTO, 1999). NARSTO is apublic/private partnership, whose membershipspans government, the utilities, industry, andacademe throughout Mexico, the UnitedStates, and Canada. Its primary mission is tocoordinate and enhance policy-relevantscientific research and assessment oftropospheric pollution behavior, with thecentral programmatic goal of determiningworkable, efficient, and effective strategies forlocal and regional air-pollution management.

The evolving US national program focusing onthe risks and management of the healtheffects of fine particles has four majorcomponents:

Health Science. Establishment of asystematic approach to substantiallyadvance knowledge about the mechanismsand specific insults leading to healthconsequences of exposure to fine particlesin ambient air. The health sciencecomponent recently has beenestablished through the efforts of the

Environmental Protection Agency (EPA)following the recommendations of the

NRC Committee.

Monitoring Networks.Establishment of ahierarchy of measurement sites nationwidefor monitoring the mass concentration,chemical composition and size distributionof fine particles. A national network ofmeasurements and air monitoring has

been designed and is beingimplemented through the EPA, the

Department of Agriculture, theDepartment of Interior, and state

environmental authorities.

Emissions.Establishment of a program todetermine the emissions of fine particlesand their gaseous precursors that willpermit the preparation of much moreeffective management strategies. Theinvestigations leading to improvementin knowledge of emissions involve work

of EPA, the Department of Energy(DOE), state and local air quality

management agencies, and the privatesector, including the electric utilities(e.g., EPRI, the Electric Power Research

Institute), the fossil fuels industry (e.g.,American Petroleum Institute) and the

t ransportat ion industry (e.g. ,Coordinating Research Council).

Atmospheric Processes. Improvingknowledge about the atmosphericprocesses that govern the characteristicsand evolution of airborne particles so thatmethods for quantitatively linking emissionwith exposure can be made available formanagement purposes. The investigationof tropospheric aerosol processescurrently is supported by a number of

sponsors in the public and privatesectors, including DOE, the National

A t m o s p h e r i c a n d O c e a n i c Administration (NOAA) and the National

Science Foundation (NSF).

These four components of the nationalprogram are coordinated through the AQRSand NARSTO. A compilation of particulatematter research activities in the United Statesis maintained by the Health Effects Institute(HEI, 2001).

Critical Mass. Much progress has beenmade recently in initiating programs to meetthe national needs through the first twocomponents, health science and monitoringnetworks. Progress has also been made in

the emissions arena, however accurateemission inventories remain a large area ofuncertainty in linking what is present in the airto what is emitted by natural andanthropogenic sources. Similarly, while muchpioneering research in atmospheric processeshas been accomplished by NOAA and otheragencies, including DOE, these efforts havenot yet reached critical mass.


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Introduction

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There are substantial and critical gaps inknowledge and understanding of theatmospheric processes associated withaerosols, and so the Tropospheric AerosolProgram (TAP) is being developed tocomplement on-going efforts at NOAA andother agencies, to help fill those gaps.

The research program presented here, theTropospheric Aerosol Program (TAP), will bea sustained and cohesive means ofinvestigating atmospheric processes affectingairborne particles, focusing on theatmospheric transformation processes thatgovern the mass concentration, chemicalcomposition, and microphysical properties offine atmospheric particles.

TAP will therefore specifically address thefourth research component of the nationalprogram, improving knowledge of atmosphericprocesses governing loading and properties offine atmospheric particles. TAP will takeadvantage of new measurement technologiesfor gases and particles that have emerged inrecent years and will enhance the state of theart of measurement and characterization offine particles. TAP will thus contributesubstantially to the measurement data base ofloadings and properties of fine particles,thereby considerably augmenting the second

component of the national fine particleresearch effort noted above.

Because the atmospheric loading of fineparticles derives in great measure from energyproduction and use, and because of DOE'sstatutory responsibility to conduct researchinto the environmental consequences ofenergy-related activities, DOE is prepared toorganize and act as the principal agent forTAP.

This Program Plan presents an overview ofthe research to be conducted in TAP. Thisplan is a natural outgrowth of reviews,assessments, and workshops undertaken overthe past few years by the NRC (NRC, 1998,1999, 2001), the AQRS (AQRS, 1998, 1999),NARSTO (NARSTO, 1998a, b, c; Hales, 1998;Hidy et al., 1998), and by several of the DOElaboratories (PNNL, 1999).

TAP will

focus on the

atmospheric

transformation

processes

governing

aerosol

loading,

composition,

and

properties.

This plan was prepared at the initiative of theDOE Office of Biological and EnvironmentalResearch (OBER) (within the DOE Office ofScience) in response to these crucial nationaland energy-related needs. These effortswere also encouraged by and coordinatedwith colleagues in the DOE Office of EnergyEfficiency and the DOE Office of FossilEnergy.

After a draft version of this document hadbeen circulated, a workshop was held atBrookhaven National Laboratory in June,1999, to gain input from a broad communityrepresenting scientists from DOE NationalLaboratories, other Federal laboratories,academia, and the private sector, and officialsin the various Federal agencies responsiblefor air quality and aerosol research. A list ofparticipants is given in Appendix A.

Following the Workshop a PreliminaryProgram Plan was prepared incorporatinginput from workshop participants and others towhom the draft had been made available.That document was circulated to Workshopparticipants and to other scientists andofficials in the several cognizant Federalagencies and was made available on theWorld Wide Web. This Program Plan is arefinement of that document that takes intoaccount comments and suggestions on the

Preliminary Program Plan.

1.2 PriorityComponents ofTAPThe principal objective of TAP is to determinethe role of atmospheric processes ingoverning the physical and chemical

characteristics of aerosols that are responsiblefor human health effects. These processesare the link between the emissions that areresponsible for atmospheric aerosols andaffected individuals who breathe them.Mathematical models of these processes arethe primary tools scientists use to organizescientific knowledge into a comprehensiveunderstanding of these links betweenemissions and exposure.


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TAP Program Plan

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Highest

prioritycomponents

of TAP

research are

chemical

composition

of fine

particles as a

function ofsize,

chemical

dynamics and

co-pollutant

interactions,

and

estimating

the response

of fineparticle

properties to

changes in

particle and

gaseous

precursor

emissions.

Table 1.1. Illustration of Institutional Priorities for Strategic ElementsAddressing the Health Effects Associated with Airborne fine Particles

Critical element ofscientific knowledge

Key toHealth

Concern

Uncertainty inLevel ofCurrent

Knowledge

Link withAtmosphericProcesses

Currentcontributionby Others

ProposedTAP

Contribution

Number/surface/mass-particle size

distribution

H* L (H fornanoparticles)

M L H

Chemical composition-size distribution

H* M-H H M H

Particle morphology(incl. internal-externalmixtures)

H* H* L-M L-M M-H

Chemical dynamicsand co-pollutantinteraction

M-H* H H M H

Optical properties L M M M M

Physical and

meteorologicalprocesses

M-H* H H M H

Response of particleloading to change inemissions

H H H M H

Symbols H, M, and L denote high, medium, and low, respectively.

*Health research is expected to refine and improve requirements for knowledge in these areas before the

final design of TAP.

They are also the tools that regulators mustuse in determining how changes in emissionsmight affect human exposure to atmosphericaerosols and, consequently, their humanhealth effects. Construction of models thatrelate emissions of air pollutants toambient airconcentrations and to their physical andchemical characteristics will, therefore, be aprimary focus of TAP research.

Experience has shown that development andtesting of these models is best achieved byconducting a series of field experiments,guided and supported by theoretical andlaboratory studies, that focus on the keyprocesses that govern aerosol formation,transformation, transport, and removalintegrated by analysis and interpretationleading to preparation and evaluation of themodels.

Table 1 lists critical elements of scientificknowledge that are needed to understand thelinks between emissions and exposure. Alsoincluded is an assessment, based on currentknowledge, of the relative importance of theseelements to human health concerns.

Recently representatives of different agenciesof the Federal government and industry werepolled to estimate the priorities (high, mediumand low) that each of the components listed inTable 1 would have for advancing knowledgerelevant to managing health risk fromexposure to fine particles. The results areincluded in the table to illustrate the prioritysetting the TAP community proposes to refinein developing its design.

The results strongly suggest that the highest

priority components for initial TAP planning


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Introduction

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include the chemical composition of fineparticles as a function of their size, thechemical dynamics and co-pollutantinteractions of fine particles, the physical andmeteorological influences on fine particleconcentrations, and the means to estimate theresponse of fine particle properties withchanges in particle and gaseous precursoremissions.

In keeping with the present outlook of theAQRS, advancing the knowledge of regionalhaze and the component of aerosol forcing ofclimate change are designated second andthird priorities for TAP. Because the origins ofregional haze are closely linked with fineparticle concentrations at the surface andaloft, new knowledge of the sourcescontributing to haze will emerge naturally from

TAP experiments.

The field experiments envisioned in the TAPdesign will incorporate a major airbornesampling component. Thus important targetsof opportunity will present themselves toconduct cooperative projects with atmosphericradiation research projects to determine thefine particle optical effects that bear onvisibility and radiative transfer over urban andrural areas of the U.S.

1.3 Benefits to beDerived from TAPThe US has relied on a number of strategiesto reduce particulate air pollution over the pasttwenty nine years. As air quality hascontinued to improve, decision makers haverecognized that the management of majorpollutants requires consideration of theconsequences to one component withchanges in another. The recognition of

interactions between pollutants creates theneed for highly complex conceptual models tominimize the risks of overly simplisticdecisions for emissions reductions.

Although significant progress has been madein improving the nations air quality,substantial costs have been incurred. Thepotential additional costs per increment ofimprovement in air quality are expected to rise

significantly in meeting up-dated NAAQS.Therefore, it is critical to acquire newknowledge about the fine particles and theirlinkages to other air pollutants to insure thatcontinued investment in air qualityimprovement will achieve the goal of greatlyenhanced public health and welfare at minimalcost.

The research to be conducted by TAP,described in this Program Plan, togetherwith that of other agencies, will providemajor advances in knowledge about theprocesses that govern evolution of fineparticles in the troposphere.

This knowledge will be used as a primarymeans to advance the development of greatly

improved predictive capability for aerosolparticle loading, properties, and geographicaldistribution that is required for informeddecision making.

Decision making needs to rely increasingly onthe ability to examine the consequences ofalternative strategies to achieve a given airquality objective, which may take a forminvolving either mass concentration orchemical composition, or both. The principalmeans of achieving this objective lies in theapplication of reliable air quality models.

With the national program addressing inparallel the four major elements of the fineparticle problem, and with TAP serving as afocal point for atmospheric processes, this willprovide in the next decade a timely andcomplete portfolio for creating greatlyimproved air quality models relating sourcesand human exposure to fine particles, andco-pollutants. This knowledge will aidsignificantly in creating methods for selectionof optimum strategies to reduce the healthrisks of exposure to fine particle incombination with gaseous components,including ozone, sulfur dioxide, and thenitrogen oxides.

The secondary benefits of TAP will includenew knowledge about the optical properties offine particles, as well as their evolutionaryprocesses which, in turn, will fill gaps inimportant knowledge needed for considering


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TAP Program Plan

6

reductions in regional haze, and for particleinfluences on climate alteration.

1.4Consequences

of Not Doing thisResearchThe nation has committed major resources toresolve the human health consequences ofexposure to fine particles in the atmosphere.This problem is an exceedingly complex onethat has eluded effective solutions despite along history of research and air qualitymanagement practice over the past thirty

years.

The necessary resources have beencommitted through recent Congressional andadministration actions to attack the healthconsequences of fine particle exposure.However, a comparable commitment for theparallel development of the necessary,advanced tools to inform decision makersabout ambient air management is not yetavailable.

The capabilities of the scientific community

are commensurate with the formidable task ofobtaining this kind of information, but need tobe focused in cohesively through acooperative and collaborative initiative such asTAP, in the framework of the nationalprogram.

The timing of investigations leading to majorimprovements in mathematical models forquantifying emissions to ambient airconcentration (and human exposure) is criticalto insure that timely strategies can bedeveloped as early as possible to minimizethe risk of delaying pollution managementdecisions, or taking a less than optimaldirection in management approaches.

If the national fine particle program engages inresearch on only two of the four majorstrategic elements, the necessary advancedinformation for decision making will bedelayed far into the future. TAP offers theopportunity, at a level of $20-40 million a year,to focus the necessary scientific resources toaddress the fourth component of the national

research program on fine particles.

At this critical level of commitment, initiatingTAP at this time will insure that its productswill be available for strategy development inthe period 2005-2011. This is the period whenthe NAAQS for fine particles will be reviewedagain in its five year cycle, and when critical,major decisions will be made forimplementation of national efforts to reduceairborne particle exposures simultaneouslywith resolving parallel problems associatedwith tropospheric ozone, and regional haze.

Without the benefit of results from TAPthere is a significant risk of choosing anon-optimum and hence less efficient ormore costly pathway to a combinedsolution for these problems.


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TAP is a

highlyfocused

observational

and analytica

research

effort that will

compare

observations

and modelcalculations

to improve

capability of

modeling

aerosol

loadings and

properties

within known

andreasonable

accuracy.

2. Overview andBackground

2.1 Development of

TAPThe Tropospheric Aerosol Program (TAP) is aprogram being developed by the Office ofBiological and Environmental Research(OBER) of the Department of Energy directed

to gaining improved scientific understandingand model-based representation of theprocesses controlling the mass loading,geographical distr ibut ion, chemicalcomposition, microphysical, and opticalproperties of tropospheric aerosols. Thisprogram is a continuation of DOE's effort todevelop understanding and predictivecapability for the atmospheric influence ofenergy-related activities and their effect onhuman health and welfare. The TAP programis a highly focused observational andanalytical research effort that will compare

observations and model calculations toimprove this modeling capability within knownand reasonable accuracy.

This Preliminary Program Plan specifies theobjectives of TAP and presents the need forthis understanding and capability to representthese processes in atmospheric models. ThePlan then presents the approach that will betaken by TAP to conduct the researchnecessary to develop this understanding andmodel-based representation.

2.2 Fine Atmospheric

Particles

Aerosol particles in the atmosphere resulteither from introduction of particles into theatmosphere (primary aerosols) or from

conversion of gaseous substances in theatmosphere to particulate matter (secondaryaerosols). Aerosols result from naturalprocesses and from human activities.Examples of natural aerosols are sea saltresulting from breaking waves, windblownmineral dust, smoke from wildfires, and thenatural haze that is recognized in place namessuch as the Blue Ridge Mountains. Aerosolsfrom human activities include smoke anddiesel exhaust as well as visibility reducing"industrial haze" or "smog." In cities andnearby regions anthropogenic aerosols (thatis, aerosols resulting from human activities)dominate aerosol loading.

Motivated by the desire to protect humanhealth, the U.S. has recently adopted a newNational Ambient Air Quality Standard(NAAQS) which for the first time sets a limit onthe mass loading of particulate matter ofaerodynamic diameter of less than 2.5 m

(termed the PM-2.5 or fine particle standard).The restriction of this standard to fine particlestakes into account the understanding that fineparticles are capable of penetrating well intothe lungs with the resultant possibility of healthimpairment. Two standards have beenissued: annual average concentration, 15 g

New Ambient

Air QualityStandards for

the first time

limit mass

loadings of

fine particles.

m-3, and 24-hour average, 65 g m-3. Theneed to achieve the national standards isbased on an increasing body of evidence thatindicates that fine particulate matter in theatmosphere is responsible for adverse humanhealth effects. The increased focus on the fine

particles comes as a result of advancingknowledge of the apparent risk of inhalingpollutant aerosols with the potential forexacerbating respiratory ailments and otherdiseases.

The PM-2.5 standard, as is the case forambient air quality standards generally,imposes a requirement on states and other

jur isdict ions to achieve a specif ied mass


16/98


17/98

Overview and Background

9

TAP will

focus on the

life cycle of

atmospheric

aerosols.

and dispersion processes that govern localconcentrations, in brief the processesresponsible for aerosol loading at a givenlocation. Figure 2.1 makes it clear that therewill be no single answer to these questionsthat is applicable to the entire country.Likewise it is reasonably anticipated that theanswers to these questions will depend alsoon season as a consequence of seasonaldependence of the mix of anthropogenic andnatural emissions and also seasonaldifferences in controlling meteorology andatmospheric chemistry.

Understanding the processes that control theloading, distribution, and properties ofsubmicrometer aerosols is going to be difficult.Aerosols are chemically and physically much

more complex than gaseous pollutants, andthe overall process governing aerosolloadings, properties, and distributions is muchmore complex than for primary pollutants suchas SO2 and CO. Aerosols are veryheterogeneous in composition and sources,ranging from seasalt, dust and tire particles, tosulfates, nitrate, organics and soot, as well asmixtures of these materials. Some of theaerosols are emitted directly as particles,whereas others form in the atmosphere fromgaseous precursors, both anthropogenic andnatural. While in the atmosphere aerosol

particles grow in size and evolve incomposition through adsorption and reactionof gases and through coagulation and canchange phase by deliquescence andefflorescence. They are removed through wetand dry deposition processes which aredependent on the composition and size of theparticles.

There are numerous activities required tounderstand and quantitatively describe theloading and properties of sub 2.5 m particles,from generating emission inventories to

regional monitoring, to developing theknowledge of the fundamental processes thatcontrol loading of tropospheric aerosols andconcentrations of specific classes ofcompounds. The latter processes, whichconstitute what might be denoted the"atmospheric life cycle" of these aerosols,are the principal focus of TAP. A recent NRC

report called for development of advancedmathematical, modeling, and monitoring toolsto represent the relationships between specificsources of particulate matter and humanexposures and for linking sources oftoxicologically important constituents andcharacteristics of particulate matter to exposedindividuals and populations. (NRC, 1998). Butthis cannot be done without understanding ofprocesses that control these relationships.This is where DOE comes in, with expertise inatmospheric aerosol science, in conductinglarge-scale field projects, in numericalmodeling of atmospheric chemistryphenomena, and in laboratory studies andtheory. In this effort we fully expect tocomplement and leverage other federalprograms, principally those of EPA, NASA,

NOAA, and NSF. These agencies have alldeclared PM-2.5 research as a high priorityresearch focus for the near future. As hasbeen shown in the past, coordinated work bymultiple agencies is the key to real progress.

Closely related to the PM-2.5 issue is theissue of visibility impairment due to aerosols.As recently as April 22, 1999, Vice PresidentGore along with Environmental ProtectionAgency Administrator Browner announced amajor new effort to improve air quality innational parks and wilderness areas. The new

regional haze rule (Code of FederalRegulations, undated) requires states todevelop implementation plans to preventimpairment of visibility in National Parks andother pristine locations, with the objective,ultimately, of attaining natural visibilityconditions by 2064. The principal contributionto visibility impairment is from fine (sub 2.5 mdiameter) particles, which are highly efficientscatterers of visible radiation and whoseconcentrations are closely correlated with theatmospheric light scattering coefficient (Figure2.2). Whatever the ultimate regulations thatare imposed to protect and improve visibility, itis clear that developing a strategy to achieveany such standards requires the sameunderstanding of the processes that controltropospheric aerosol loading and properties asis required to develop strategies to meet thePM-2.5 standards.


18/98

TAP Program Plan

10

Figure 2.2. Time

series of l ight

scattering coefficient

and fine particle

mass in Stockton

CA in January 1994.

Light scattering

coefficient is scaled

to fine particle mass

by daily averages.

From Husar (1997).

Another related environmental issue is aciddeposition. The recent report from theNational Acid Precipitation AssessmentProgram (NAPAP, 1998) indicates that it is tooearly to determine whether changes in aquaticecosystems have resulted from emissionreductions in response to the 1990 Clean AirAct Amendments. The report notes that overthe last 13 years New England lakes haveshown evidence of recovery from acidificationbut in contrast that the majority of Adirondack

lakes have remained fairly constant and thatthe most sensitive Adirondack lakes havecontinued to acidify. The EPA has reported to

Congress that additional reductions in sulfurand nitrogen deposition will be required to fullyrestore sensitive Adirondack lakes. Sulfateand nitrate, major components of fine particlemass (Figure 2.1) and their gaseousprecursors sulfur dioxide and nitrogen oxidesare the major contributors to acid deposition.Figure 2.3 shows that concentrations ofaerosol sulfate and of nitric acid vapor, a majoraerosol precursor, show no indication ofdecrease over the past 12 years in nonurban

regions of the Northeast.

14

12

10

8

6

4

2

0

SO4

2-,gm-3

8

6

4

2

0

HNO3,gm-3

98979695949392919089888786

Year

Figure 2.3. Time series of

concentrations of sulfate

aerosol and nitric acid

vapor at a site near State

College, Pa. Adapted

from NAPAP (1998), with

update from B. Hicks,

NOAA, Air Resources

Labo ra to ry (p r i va tecommunication, June

1999). Data points are 5-

week running mean of 1-

week samples.


19/98


11

Uncertainties

due toaerosols

preclude

quantitative

attribution of

climate

change over

the past

century to

industrialgreenhouse

gases.

There is a

major gap in

research to

describe the

life cycle of

tropospheric

aerosols as it

pertains toradiative

forcing of

climate

change.

Lastly, research in the last decade hasindicated that aerosol particles have apotentially significant influence on radiativeenergy exchange processes in theatmosphere. Anthropogenic aerosols scatter

solar radiation and modify cloud reflectivity,thereby exerting a cooling influence onclimate. This cooling influence is thought to beoffsett ing a substantial fraction ofanthropogenic greenhouse warming, but itsmagnitude is highly uncertain. Thisuncertainty precludes confident empiricaldetection of climate change due to increasedgreenhouse gases and quantitative inferenceof climate sensitivity. It also precludesevaluation of performance of global climatemodel simulations so that it is impossible atpresent to answer the question of how much of

the 0.6 degree temperature rise over the pastcentury can be ascribed to industrialgreenhouse gases and how much to naturalvariation. Much of this uncertainty arises frompresent limited ability to quantitatively describethe aerosol loading and microphysicalproperties that govern their light scattering andcloud nucleating ability.

Shortwave radiative forcing of climate changeby aerosols by the direct and indirectmechanisms has been identified by the

Intergovernmental Panel on Climate Change(IPCC) as the greatest uncertainty in forcing ofclimate change over the industrial period(IPCC, 1996). In 1996 a NRC panel,convened at the behest of DOE, NASA,NOAA, and NSF, issued an urgent call for acoordinated program of research to quantifythis aerosol forcing (NRC, 1996). Since thattime rather little has been initiated. As we getready to face the next millennium and draft apolicy to mitigate or accommodate to theanticipated climate change, it is imperative toresolve this largest scientific uncertainty in

climate forcing.

While research programs that deal withclimate change, including the DOEAtmospheric Radiation Measurement Program(ARM, 1999; Stokes and Schwartz, 1994),examine the radiative effects of aerosols, thereis a major gap in research to quantitativelydescribe the life cycle of tropospheric aerosolsas it pertains to this radiative forcing, research

that is more properly identified as in thedomain of atmospheric chemistry and whichbuilds on the techniques and capabilities ofthis discipline. Understanding the radiativeinfluence of aerosols requires field studies that

provide a seamless link of understandingconnecting aerosol emissions, secondaryformation and evolution, chemical, physical,and optical properties, and deposition togetherwith examination of radiative influences.Ultimately what is required are models thataccurately represent aerosol loading, i.e., theamount and geographical distribution ofaerosols in the atmosphere, and the so-calledintensive properties of these aerosols, themicrophysical and optical properties thatgovern their radiative forcing per massloading. At present representation of aerosol

processes in climate modeling is in its infancy,and to the extent that this is done at all, it isdone in a quite simplistic way that does nottake into account the heterogeneity of sizeand composition that is characteristic ofaerosols. For example because of lack ofknowledge and model based representation ofaerosol composition and properties, there hasthus far been a tendency, to the extent thataerosol properties are addressed in models atall, to treat all aerosols as if they werecomposed of ammonium sulfate at 25C.However it is known from recent results that

aerosol deliquescence and hygroscopicgrowth, and hence optical properties, dependmarkedly on composition and temperature. Itis therefore necessary to develop theknowledge base that can handle thecomplexity of actual aerosols.

It seems likely that solving the greenhouse-gas climate change issue will also require asignificant change in the nation's energyeconomy at a cost of billions of dollars.Moreover, by virtue of the fact that aerosols

couple air quality with climate change ouractions to overcome one of these challengeswill affect the other. In this context it isurgently imperative that the aerosol forcing beplaced on a much more quantitativefoundation than is available at present.

The management of these interrelatedenvironmental stresses poses a majorchallenge to decision-makers, in terms of both


20/98

TAP Program Plan

12

the atmospheric processes and themechanisms of effects on humans and theenvironment. Recently the United States EPAhas created a major goal to document thenature of ground-level airborne particles andhas challenged the health and atmosphericscience community to identify the specificatmospheric agents responsible for adverseeffects of particulate pollution [EPA, 1999b]These initiatives are superimposed oncontinuing research on visibility reducingpollution and on the influence of particles onclimate alteration. The Tropospheric AerosolProgram (TAP) will complement the initiatives

just under way in the monitoring and healtheffects areas, and add substantially to thecapabilities for advancing methods forpredicting the response of atmospheric

pollution exposure to emissions managementoptions.

2.3 The DOE Context

The fact that much of the tropospheric aerosolburden is believed to result from energyproduction and use focuses attention on thiskey component of the nations well-being inthe context of meeting the nation's energyrequirements in the next century.Understanding the environmental influences of

energy production and use and ways tominimize these influences is a necessarycomponent of DOE's National EnergyStrategy, which has an explicit goal to promoteenergy production and use in ways thatrespect health and environmental valuesimproving our health and local, regional, andglobal environmental quality (DOE, 1998a).

Referring explicitly to PM2.5 particles formerSecretary of Energy Bill Richardson hasstated, "These unseen particles may poserespiratory problems for certain portions of the

population, and for this Administration, there isno higher priority than protecting the health ofour citizens. . . At the same time, if our cleanair regulations are to be fair and scientifically-sound, we need to understand much better thelinkage between the levels of these pollutantsin the atmosphere and their sources, bothhuman and natural." (DOE, 1998b). The TAPprogram is specifically directed to developingthis understanding.

The objective of TAP should be viewed in thecontext of the national portfolio ofmeasurements and research on atmosphericaerosols. There are many elements that mustbe implemented in order to be able to meetthis country's requirements, and the severalFederal agencies have di f fer ingresponsibilities in this respect, although to besure the boundaries that separate theseresponsibilities are somewhat ill defined.EPA's responsibilities include developmentand evaluation of emission inventories ofaerosols and aerosol precursors, monitoring todetermine the extent of compliance/non-compliance with air quality standards, andepidemiological studies to quantify aerosolhealth effects. NOAA has responsibility forlong term monitoring of aerosol loading and

properties at a small number of sites. Some ofthese elements are in place now and some ofthem are being enhanced. A nationalmonitoring network will undoubtedly produceinvaluable data, but without the supportingmechanistic knowledge, its value is verylimited in providing guidance for developing anefficient control strategy or in evaluatingpresent, past, or future aerosol influences onclimate.

If the goal of a national aerosol programincludes, as it should, developing the

capability to devise effective strategies forcontrol of aerosol loadings and the ability toquantitatively estimate aerosol influences onclimate, it is essential to acquire fundamentalunderstanding of the atmospherictransformation processes governing theloading and properties of troposphericaerosols. This process-level understanding isfundamental to constructing models that aregenerally applicable, not just to a limited rangeof conditions, so that they may be applied to awide variety of situations, for examplemodeling for previous emission scenarios in

order to develop a historical record of forcing,or modeling for various emission scenarios toanswer what if type questions. The DOEAtmospheric Chemistry Program (ACP, 1999)has demonstrated outstanding capability toperform process-level atmospheric research.To date this program has focused largely onthe fundamental processes that controlphotochemical oxidants. TAP is viewed asquite complementary to the DOE Atmospheric

TAP must be

viewed as

one

component of

an integratednational

program of

research on

atmospheric

aerosols.


21/98


13

At present

there is

insufficient

information

about theprocesses

governing the

composition

and

microphysical

properties of

tropospheric

aerosols todevelop

insightful

decisions to

minimize risk.

Chemistry Program and other DOE andfederal research programs.

TAP must be viewed as one component of anintegrated national program of research onatmospheric aerosols. It is essential that theprograms of the several agencies be closelycoordinated. The DOE component of thenational program is process research todetermine, quantitatively describe, andrepresent in models the mechanismsgoverning the mass loading, composition, andmicrophysical and optical properties oftropospheric aerosols, and their geographicaland vertical distribution.

TAP will contribute to the DOE/OBERresearch effort directed to understanding the

basic chemical and physical processes of theEarth's atmosphere and how these processesmay be affected by energy production anduse. This understanding will ultimately permiteffective mitigation of the long-term health andenvironmental consequences of energyproduction and contribute to optimal use ofdiffering technologies.

2.4 The Science

Context for TAP

Although recognized for some time, theimportance of tropospheric aerosols hasrecently been highlighted with respect to theirinfluence on human health (NRC, 1998) andradiative forcing of climate change (NRC,1996).

At present, despite a history of continuedatmospheric research, there is insufficientinformation about the processes governingthe composition and microphysical properties

of tropospheric aerosols available to developin a modern context insightful decisions tominimize the risk from these aerosols. Thelack of information centers in the details ofprocesses shaping the chemical compositionas a function of particle size, especiallyregarding the carbonaceous and reactivenitrogen components, both of which are majorconstituents of fine particulate matter innumerous locations (Figure 2.1).

Examination of composition of troposphericaerosol particles as a function of particle sizeindicates a wide range of variation, with muchof present-day energy related contributionsresiding in the fine particle range. Combustionprocesses tend to produce very finely dividedparticles, formed either directly in the sourceor in the air near the source. Thesenanoparticles are present in large numbersnear sources but are rapidly agglomerated inthe air.

Health effects research over the years hasindicated the importance of particle size inrespiratory disease. The fine particle fractionof the particle-composition distribution has thegreatest likelihood of affecting the lower lungs,where oxygen exchange takes place. Since

recent health studies have identified sub-2.5m particles as a potential respiratoryinflammatory agent, there is a need tocharacterize this fraction and its growth aswell as the particle properties quantitatively forcomplex human exposure assessments. Thiskind of research is highly demanding ofmeasurement capability since it requiresscanning the particle size spectrum, whichvaries over at least three powers of ten in size,and more than seven powers of ten inconcentration.

Other hypotheses advanced by the healtheffects research community relate observedhealth impacts to specific chemical factorsincluding: metals, acids, organic compounds,biogenic particles, sulfate and nitrate salts,peroxides, soot, and gaseous cofactors(Albritton and Greenbaum, 1998). In order tomake progress in establishing which of theseagents are causative and the effects of PMcontrol measures, it is necessary tounderstand the relations between emissionsand the size-dependent composition of theambient aerosol. Thus, demands of chemical

speciation must be added to the task ofdetermining size spectra over many orders ofmagnitude. Both measurements andpredictive models are required.

The reactive nitrogen and carbonaceouscomponents are closely linked with sulfurspecies and are interactive with oxidantproduction in the troposphere. Through thework of the last two decades the chemistry


22/98


23/98


15

required. Progress will depend on acombination of major advances in knowledgethrough field experimentation, laboratoryinvestigations, and synthesis of informationinto mathematical models.

2.5 The TAP

Approach

Experience in atmospheric chemistry hasshown that measurements cannot besufficiently dense in space and time to meet allrequirements, nor can measurements bythemselves lead to predictive capacitynecessary for developing approaches to meetair quality requirements. The situation is evenmore complicated in the case of atmosphericaerosols, which are highly heterogeneous fromlocation to location (Figure 2.1) necessitatingprocess-level understanding and precludingthe utility of any "one size fits all" aerosolmodel. Likewise, empirical models will not betransferable to changing mix of emittedmaterials, changing atmospheric chemicalenvironment or the like.

For these reasons TAP will consist of asustained analysis and interpretation of resultssupported by a portfolio of tightly coupledresearch activities consisting of four principalcomponents:

Field Measurements of aerosol propertiesand transformation processes.

Modeling transport and transformation oftropospheric aerosols.

Development of instruments and advancedmethods of aerosol characterization.

Laboratory experiments and theory directedto aerosol processes.

The coupling of these several elements isindicated schematically in Figure 2.4. The

field program is the centerpiece of TAP. Theother elements are coupled not just to the fieldprogram but also to each other to maximizethe synergism and utility of the entire TAPProgram. These elements will enable the TAPscientific team to bring the atmosphericscience of fine particles to the level necessaryto bring informed energy and environmentalmanagement for the next several decades.

FIELD

MODELING

LABORATORY

&

THEORY

INSTRUMENTATION

& ADVANCED

CHARACTERIZATION

Figure 2.4. Science Elements of TAP.


24/98

This page intentionally left blank


25/98

17

TAP willdevelop the

fundamental

scientific

understanding

required to

construct

tools for

simulating thelife cycle of

tropospheric

aerosols--the

processes

controlling

their mass

loading,

composition,

andmicrophysica

properties--al

as a function

of time,

location,

altitude, and

ambient

conditions.

3. The TAP Objectives

3.1 What TAP will

Accomplish

The goal of TAP will be to develop thefundamental scientific understanding requiredto construct tools for simulating the life cycle oftropospheric aerosols--the processescontrolling their mass loading, composition,and microphysical and optical properties--allas a function of time, location, altitude, andambient conditions. The TAP approach toachieving this goal will be by conductingclosely linked field, modeling, laboratory, andtheoretical studies focused on the processescontrolling formation, size, chemicalcomposition, optical properties, transport, anddeposition of tropospheric aerosols. Thisunderstanding will be represented in modelssuitable for describing these processes on avariety of geographical scales, from tens tothousands of kilometers; developing andevaluating these models will be a key

contribution of TAP. In carrying out thesetasks TAP will work closely with otherprograms in DOE and in other Federal andstate agencies, and in the private sector,directed to related aerosol issues.

3.2 TAP Research

Tasks and Scientific

Issues

The following are examples of the principalresearch tasks and scientific issues regardingtropospheric aerosols which will beaccomplished by TAP or which the researchconducted in TAP will resolve and/or providethe physical understanding and model-basedrepresentation to permit resolution in particularsituations of interest.

Charac ter ize the s ize-dependentcomposition, microphysical properties, andother relevant properties of atmosphericaerosols, including optical properties, at thesurface and throughout the vertical column,during TAP field projects.

Determine the accuracy with which aerosoloptical properties (light scattering coefficient,absorption coefficient, light-scattering phasefunction) can be calculated from knowledgeof size distribution, chemical composition,

and composition-dependent properties suchas refractive index.

Determine the accuracy of emissioninventories for primary aerosols and foraerosol precursor gases in locations of TAPfield projects.

Determine the fundamental processes thatcontrol new particle formation in theatmosphere and the dependence of therates of these processes on controllingvariables.

Determine the processes contributing to theaccumulation of mass on pre-existingatmospheric aerosol particles and thedependence of the rates of these processeson controlling variables.

Develop the ability to describe theinteraction of atmospheric aerosol particleswith water vapor and the dependence of thisinteraction on particle composition andsurface properties and on ambientconditions.

Determine the rate of dry deposition as aremoval process for aerosol mass andnumber and its dependence on particle sizeand composition.

Determine the influence of meteorologicalprocesses, such as turbulent mixing inconvective systems and accumulation inhigh- and low-pressure systems, in-cloudreactions, precipitation scavenging, on


26/98

TAP Program Plan

18

temporal variation of aerosol loading andproperties.

Determine the influence of aerosol loadingand properties on gas phase chemistry assites of heterogeneous catalytic reactions,

as sinks of gas-phase species, and bychanging the actinic flux.

Develop model-based tools to determine thefraction of the aerosol mass observed at agiven location that derives from primaryemissions versus gas to particle conversionin the atmosphere.

Develop model-based tools to determine thefraction of aerosol mass at a given locationthat is anthropogenic versus natural.

Determine the geographical and verticalscale that is required for physical simulationmodels to describe PM-2.5 exceedances.

Determine the spatial and temporalresolution required in models to representaerosol loadings and properties on aregional scale in order to provide realisticestimations of effects of emission control.

Determine the computing power required torepresent aerosol loading, and size resolvedchemical, and physical properties insimulation models.

Develop methods to parameterize aerosolprocesses in regional to continental scaleair-quality models and in global scale climatemodels.

Determine the accuracy with which physicalsimulation models describe aerosol loading,

composition, size distribution and opticalproperties.


27/98

19

4. Organizational Structure

4.1 Organizational

Elements of TAP

The organizational structure of TAP isdesigned to meet the needs of a complexscientific research program that will consist ofindividual research projects all directed to acommon set of goals, and to being responsiveto the management requirements of DOE.

The management and organizational structurefor the program as presently envisioned issketched in Figure 4.1. The major features ofthe program's organization are as follows.

1. Direct management of the Program by aProgram Director in the EnvironmentalSciences Division of DOE's Office ofBiological and Environmental Research.

2. Interagency Coordination, primarily throughthe Federal Air Quality ResearchSubcommittee (AQRS) and the variousNARSTO working groups, to ensure closecoordination with other programs.

3. A Lead Scientist, who must be an aerosolscientist with broad experience, will haveoverall responsibility for the implementationof TAP, with consultation with DOE andwith the Scientific Steering Committee, forthe scientific leadership of the program and

for representing the program within thescientific community.

4. The Science Team will consist of thePrincipal Investigators of the scientificprojects comprising TAP. Science projectswill be selected competitively throughproposals in response to DOE ProgramAnnouncements, or through jointannouncements with other agencies.

Tropospheric Aerosol Program

Science Support Team

DOE

EnvironmentalSciences Division

InteragencyCoordination

Lead Scientist

Science Team Investigators

Steering Committee

Field Investigators Team

Chief of Operations

NARSTO

TAP Project Support

Science Support

Management Team

Science TeamScience Support

Executive

SteeringCommittee

WorkingGroups

Figure 4.1. Organizational structure of TAP including DOE management oversight and Interagency

Coordination, and showing linkage to the national research effort on tropospheric aerosols through

NARSTO.


28/98

TAP Program Plan

20

5. The Scientific Steering Committee willconsist of representatives from each of thefour programmatic areas of TAP and will, inconjunction with the Lead Scientist and theresponsible DOE officials, set the scientificdirection for TAP. The SSC will conductperiodic reviews of the set of TAP projectsto ensure that key gaps in knowledge arebeing filled and to identify any researchneeds that are not being met. This willkeep TAP focused on research critical tounderstanding PM2.5 and related issues forwhich where understanding of aerosolproperties and evolution is required. TheSSC will also function as a recruiting entityto insure that outstanding investigatorsparticipate in TAP and commit to getting"answers" that are needed.

6. The Field Investigators Team will consist ofthe principal investigators of field studyteams, the principal scientific groupsparticipating in the Field Campaigns ofTAP, as described in Section 7. This teamwill define major field projects of TAPincluding selection from their membershipof Project Scientists responsible for leadingindividual projects.

7. A Science Support Team under thedirection of a Chief of Operations will

provide support to TAP field and modelingoperations. Science support resources willbe allocated based upon requirements ofthe Science Team Projects with guidancefrom the Lead Scientist, the SteeringCommittee, and the Field InvestigatorsTeam, with concurrence of responsibleDOE officials. The Science SupportManagement Team will consist of theheads of the several functional activitieswithin Science Support.

8. TAP Project Support will be responsible forcontracting and other fiscal matters and forpublic relations and outreach activities.

4.2 Science Team

The Science Team will consist of the projectscientists selected based on peer review

proposals to conduct specific projects asspecified in DOE Research Announcements orthrough joint announcements with otheragencies. Successful projects will be directedto answering key questions and to foldingresults into the requisite enhanced process-level understanding and ultimately into model-based representation of these processes.Care will taken in construction of requests forproposals and in award of grants thatnecessary research components are beingaddressed, without overemphasis of somecomponents with underemphasis of others.Science team members will be encouraged toparticipate in the various NARSTO and other-agency aerosol-related working groups, andscientists funded through other aerosolresearch programs will be invited to participate

in TAP meetings and field campaigns.

4.3 Science

Support Team

The Science Support Team is seen as crucialto achieving the objectives of TAP. Thisactivity will have responsibility for:

Facilities. Provide and maintain aircraft,relocatable aerosol measurement facilities,instrumentation for field measurements.

Support for campaigns. Campaign planningand logistics; calibrations, measurementaudits.

Support for modelers. Preparation ofmeteorological drivers and gridded datasets for comparisons; establishing andmaintaining community models supportingswap in/out of modules.

Data system and archive. Incorporatemeasurements into data base/archive tofacilitate model development and testing.

The requirements and activities of the severalscience support components are presented inChapter 5.


29/98

Organizational Structure

21

TAP will be

closely linkedto ongoing

DOE projects

dealing with

the

environmenta

influence of

energy

activities.

TAP

complements

these

programs by

focusing on

the processes

that control

the loading,

geographicaldistribution,

chemical

composition

and

microphysical

properties of

tropospheric

aerosols,

especially

anthropogenic

aerosols.

4.4 Integration

An underlying philosophical tenet of TAP isthat good science must undergo the scrutiny of

peer review, in the selection of projects and inthe publication of the findings of research.Traditionally in science the latter is throughpeer-reviewed journals, and this will certainlybe a requirement for TAP investigators. It mayreasonably be anticipated that over theduration of this program such publication willincreasingly be by means of electronicpublications, which are already beingimplemented in the geophysical sciences, andwhich maintain the rigorous requirements ofpeer review while at the same time permitpublication of much richer data sets and even

the dynamics of models, in contrast to thestatic format of traditional paper journals. TAPwill actively encourage publication of findingsin such media. TAP will also provide a web-based server to facilitate dissemination ofpublications reporting TAP research. Thisweb site will serve as an active vehicle forcommunication among TAP investigators, forplanning of field programs, for exchange ofdata and models, for preparation of reports,and for active exchange of ideas that willmake TAP a truly collaborative program.

As a mission-oriented program, TAP has aresponsibility to DOE to make its findingsavailable to the user community in a way thatwill maximize the utility and use of thesefindings. A specific example is models. Theseshould be made available in readily accessibleelectronic format that will allow their use by theexternal scientific and air quality managementcommunity. Likewise, many of the fieldmeasurement data of TAP will be of broadinterest not just to TAP investigators but alsoto a variety of outside entities. To this end

TAP will facilitate dissemination of researchresults by suitable web-based approaches.

TAP will conform to the data managementpolicy of the U.S. Global Change ResearchProgram (USGCRP, 1991). This policy callsfor continuing commitment to theestablishment, maintenance, validation,description, accessibility, and distribution ofhigh-quality, long-term data sets, full and open

sharing of data, preservation of data, inclusionin data archives of information about the dataholdings, including quality assessments,supporting ancillary information, and guidanceand aids for locating and obtaining the data,adherence to data dissemination standards,and timely availability of data subject to areasonable period of exclusive use byprogram investigators.

4.5 Oversight and

Interagency

Coordination

Overall management responsibility for the

Tropospheric Aerosol Program (TAP) isprovided by the DOE Program Director.

Oversight is provided by DOEs EnvironmentalSciences Division (ESD), Office of Biologicaland Environmental Research (OBER), and theBiological and Environmental ResearchAdvisory Committee (BERAC).

Interagency coordination is provided throughthe Federal Air Quality ResearchSubcommittee (AQRS), the AtmosphericChemistry Panel of the Federal Subcommittee

on Global Change Research (SGCR), and aninteragency Aerosol Working Group.

4.6 Relation to Other

DOE Programs

TAP will be closely linked to ongoing DOEprojects dealing with the environmentalinfluence of energy activities. TheAtmospheric Chemistry Program deals with

regional to global scale global chemistry andfate of tropospheric air pollutants. TheEnvironmental Meteorology Program dealswith measurement and modeling of verticaltransport and mixing processes in the lowestfew kilometers of the atmosphere. TheAtmospheric Radiation Measurement Programis aimed at improving the understanding of thetransfer of solar and terrestrial infraredradiation in the atmosphere, and the


30/98

TAP Program Plan

22

atmospheric properties controlling thisradiation transfer and the representation ofradiation transfer in climate models in thecontext of the necessity to represent climatechange due to anthropogenic greenhousegases and aerosols.

The TAP program complements theseprograms by focusing on the processes thatcontrol the loading, geographical distribution,chemical composition and microphysicalproperties of tropospheric aerosols, especiallyanthropogenic aerosols. Specifically, TAPfocuses on atmospheric transformationprocesses governing the composition oftropospheric aerosols especially gas-to-particle conversion in the atmosphere,nucleation of new particles, growth of existing

particles, and how these processes affectaerosol composition and properties.

Atmospheric Chemistry Program (ACP).The ACP consists of a set of research projectsfocusing on chemistry and fate of troposphericair pollutants including aerosols on regional toglobal scales (ACP, 1999). Much ACP fieldwork is directed to atmospheric oxidants andrelated free radicals. Because of the strongcoupling of oxidant and aerosol chemistry, it isexpected that some field projects in TAP maybe conducted in conjunction with ACP field

projects to take advantage of chemical andmeteorological measurements that arepertinent to the requirements of both projects.

Atmospheric Radiation Measurement(ARM) Program. The Atmospheric RadiationMeasurement (ARM) Program is directed tomeasurement and model based representationof radiative transfer in the earth's atmosphereand to the processes controlling radiationtransfer, principally involving water vapor andclouds, and to lesser extent aerosols (ARM,1999; Stokes and Schwartz, 1994). The ARM

program maintains a highly instrumented sitein north central Oklahoma at which a variety ofmeasurements are employed to providedetailed characterization of the atmosphericstate and meteorological variables that controlthe evolution of the atmospheric state.continuous measurements also includeaerosol optical depth (during the daylighthours when the sun is visible, verticaldistribution of aerosol, by Lidar, and aerosol

optical properties and limited chemicalvariables at the surface. Because of thesemeasurements it may be quite attractive toconduct one or more TAP field studies at theARM Oklahoma site.

Environmental Meteorology Program. Themeasurement and modeling of verticaltransport and mixing processes in the lowestfew kilometers of the atmosphere areproblems of fundamental importance and ofmuch practical importance governing theaccumulation of air pollutants, for which a fullysatisfactory treatment has yet to be achieved.In recognition of this DOE ESD has recentlyinitiated a Vertical Transport and MixingProgram (VTMX, 1998) directed toinvestigation of vertical transport and mixing

processes in the lower atmosphere,concentrating on processes in stably stratifiedconditions, in conditions of weak or intermittentturbulence, and during morning and eveningperiods that mark transitions between stableand convective conditions with particularinterest in urban regions affected by adjacentelevated terrain (e.g., urban basins or valleys).Because of the necessity for detailedcharacterization of the meteorological situationat the times of TAP measurements it isparticularly attractive to consider conductingTAP field campaigns in conjunction with VTMX

field campaigns.

DOE Research Aircraft Facil i ty.Measurements aloft are critical to the successof TAP. A Gulfstream 159 (G-1) aircraft (DOEResearch Aircraft Facility, 1998), outfitted withinstrumentation for trace gas, aerosol, andmeteorological measurements, can bedeployed to field study locations. With a rangeof ~1,600 km and duration of ~4.5 hours, it canprovide spatial distributions of ambientvariables at altitudes from ~300 m to ~7.5 kmacross the regional scale of interest to TAP.The facility can also be used to flight test newinstrumentation systems developed withinTAP.

DOE Environmental Molecular SciencesLaboratory (EMSL).The EMSL is a nationalscientific user facility whose mission is toprovide advanced and unique resources toscientists engaged in research on critical


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environmental problems. It includescapabilities that are particularly well suited forresearch on the detection of aerosolprecursors, and on formation, growth,reactivity, and surface and bulk speciescharacterization for natural and modelaerosols. It also provides massively parallelcomputational capabilities well suited toatmospheric sciences research. Thesefacilities (EMSL, 1999) are available withoutcharge for nonproprietary research.

DOE National Energy TechnologyLaboratory (NETL) Upper Ohio River ValleyStudy. In this study (DOE, 1998b) fourmonitoring sites in the region are beingequipped with a broad array of sophisticatedequipment, both commercially-available and

still-experimental monitoring devices, to collectand analyze the small particles. Two of thelocations will be so-called "supersites" and willbe outfitted with devices to measure thechemical make-up, size and seasonalvariations of the airborne particles. At each"supersite," meteorological data, such as windspeed and direction, relative humidity, andultra-violet radiation, also will be gathered.

DOE NETL "Fingerprint" study. This study(DOE, 1998c) will examine whether fineparticulate emissions from coal-burning

systems have unique "fingerprints" that canidentify their source. Researchers will tracethe physical and chemical properties of PM2.5to the properties of the coal burned, theoperating conditions of the combustor andboiler, and the configuration and operation ofpollution control technologies.

DOE Office of Heavy Vehicle Technologies'Diesel Particulate Sampling Methodologyproject. This project is motivated by the newPM-2.5 NAAQS and alternative fuels. Theproject involves determining actual particle

size distribution and particle numberconcentrations in the exhaust plumes fromheavy-duty diesel vehicles operated on theroad. Data are then compared with datagenerated at emission test facilities todetermine if current sampling and analysismethods are adequate for characterizingparticle size and number. Then in order todetermine the zone of influence of theseemissions from a roadway, particle

transformations are examined as the plumedisperses downwind of the roadway in typicalurban situations.

Accelerated Climate Prediction Initiative.The Accelerated Climate Prediction Initiative(ACPI, 1998), sponsored in part byDOE/OBER, responds to a need within theUnited States to produce the projections ofclimate variability and climate changenecessary for the U.S. to participate ininternational assessments of climate change,as well as to understand the regional andnational effects of gl

Documents

DOE - Chemtrails - Tropospheric Aerosol Program