Framework for U.S. Air Quality Framework for U.S. Air Quality Management and Decision-makingManagement and Decision-making

Judith C. Chow (judy.chow@dri.edu)John G. Watson

Desert Research InstituteNevada System of Higher Education

Reno, NV, USA

Presented at:The Workshop on Air Quality Management, Measurement,

Modeling, and Health Effects

University of Zagreb, Zagreb, Croatia24 May, 2007

ObjectivesObjectives

• Review Air Quality Management Framework

• Introduce NAAQS establishment process

• Discuss new PM NAAQS

• Specify timeline for implementation of standards

Framework for Air Quality Framework for Air Quality ManagementManagement

Air Quality Management Theory

MonitoringInventories Analysis & Modeling

Scientific ResearchScientific Research

Determine Emissions Reductions

Track and Evaluate Results

Implement and Enforce Strategies

Develop Programs to

achieve

Establish Goals

NAAQS

Attainment date Monitoring (air and emissions)Receptor modeling

Sources complyPermitsEnforcement

Allocate reductions to source categories. Develop Implementation Plans to achieve needed reductions. (SIPs)

For Figure 2

Air Quality Management Theory

MonitoringInventories Analysis & Modeling

Scientific ResearchScientific Research

Determine Emissions Reductions

Track and Evaluate Results

Implement and Enforce Strategies

Develop Programs to

achieve

Establish Goals

NAAQS

Attainment date Monitoring (air and emissions)Receptor modeling

Sources complyPermitsEnforcement

Allocate reductions to source categories. Develop Implementation Plans to achieve needed reductions. (SIPs)

For Figure 2 Bachmann, JAWMA, 2007

U.S. Federal Air Pollution U.S. Federal Air Pollution Control Legislation Control Legislation (1963-70)(1963-70)

• The Clean Air Act (CAA) of 1963– Develop and improve state/local air control

programs (US$65M)

• CAA Amendments of 1967– Maintain state/local air programs (US$55M)

• CAA Amendments of 1970– Established structure for air quality

management (U.S. EPA set NAAQS)– EPA to regulate stationary sources

Technology-based standards for new sourcesRisk-based standards for hazardous air pollutants

Comparison of U.S. Growth Comparison of U.S. Growth and Emissionsand Emissions

Year

Pe

rcen

t ch

an

ge

Basic Facts about U.S. National Ambient Basic Facts about U.S. National Ambient Air Quality Standards Air Quality Standards (NAAQS)(NAAQS)

• The Clean Air Act directs U.S. EPA to identify and set national standards for pollutants with adverse public health and environmental effects.

• The Clean Air Act also requires EPA to review each standard at least once every 5 years.

• US EPA established NAAQS for six criteria pollutants:

– ozone, carbon monoxide, sulfur dioxide, nitrogen dioxide, lead, and particulate matter (PM)

Setting and Achieving the NAAQSSetting and Achieving the NAAQS• Setting the standards

– Health effects– Environmental effects

• Achieving the standards– Cost– Time needed to attain the standards

• Key parts of a standard:– Indicator (O3, PM2.5, etc.)– Level (e.g., 0.12 ppm, 150 µg/m3)

– Averaging time (e.g., 1 hour, 24 hours, annual)

– Form (e.g., one exceedance per year, never to be exceeded)

NAAQS Review/Revision ProcessNAAQS Review/Revision ProcessResearch on:

Atmospheric Processes,Air Quality, Exposure,Health and Welfare

Effects

Peer-ReviewedPublished Studies

EPA AirQualityCriteria

Document(AQCD)

EPA StaffPaper (SP)and Risk

Assessment(RA)

ResearchPlanning &

Coordination

Research NeedsIdentification

& Prioritization

Reviews byCASAC andthe public

PublicHearings andComment on

Proposals

FinalDecisions onStandards

ProposedDecisions onStandards

Reviews byCASAC andthe public

CASAC: Clean Air Scientific Advisory Committee

Chronology of Photochemical Chronology of Photochemical Oxidant (as Ozone) NAAQSOxidant (as Ozone) NAAQS

Year of Promulgation

Level Averaging Time

Form

1971 0.08 ppm (primary = secondary)

Hourly Not to be exceeded more than once per year

1979 0.12 ppm (primary = secondary)

Hourly Not to be exceeded more than once per year

1997 0.08 ppm (primary = secondary)

8-hr average Three-year average of the annual fourth highest daily maximum 8-hr average

2007 (proposed) 0.06 ppm(primary)

8-hr average Proposed secondary to be below 0.8 ppm in the range of 0.06-0.07 ppm

Ozone NAAQS Attainment Ozone NAAQS Attainment TimelineTimeline

Date Process

July 18, 1997 US EPA promulgates ozone NAAQS

2000 US EPA designates non-attainment areas

2003 States submit Implementation Plans for meeting the eight-hour standard. For areas which haven’t met the current one-hour standard, ongoing efforts are sufficient through the current attainment dates

2012 States have up to 10 years to meet NAAQS plus two one-year extensions

Ozone NAAQS timeline for areas Ozone NAAQS timeline for areas classified as “transitional”classified as “transitional”

Date Process

July 18, 1997 US EPA promulgates ozone NAAQS

2000 States submit Implementation Plans to address transported air pollution. US EPA classifies areas as “transitional.” All new non-attainment areas are eligible to be “transitional.”

2004 States achieve reductions from regional sources

2007 States assess effectiveness of regional reductions

2012 States have up to 10 years to meet NAAQS plus two one-year extensions

Chronology of PM NAAQSChronology of PM NAAQSYear of Promulgation

Indicator Level

Annual 24-hr

1971 TSP (Total suspended particulate matter)

75 µg/m3 (geometric mean)

260 µg/m3 (primary; not to exceed >1/yr)

150 µg/m3

(secondary; not to exceed >1/yr)

1987 PM10 50 µg/m3 (arithmetic mean)

150 µg/m3 (not to exceed >1/yr, 3 years)

1997 PM10 50 µg/m3 (arithmetic mean)

150 µg/m3 (99th percentile averaged over 3 years)

PM2.5 15 µg/m3

(arithmetic mean)65 µg/m3 (98th percentile averaged over 3 years)

2006 PM2.5 15 µg/m3

(arithmetic mean)35 µg/m3 (98th percentile averaged over 3 years)

2006 PM10 None 150 µg/m3 (not to exceed >1/yr, 3 years)

2006 (proposed but rejected)

PM10-2.5 (PMcoarse) None 70 µg/m3 (99th percentile averaged over 3 years)

PMPM2.52.5 NAAQS Attainment NAAQS Attainment

TimelineTimelineDate ProcessJuly 18, 1997 US EPA Promulgates PM2.5 NAAQS

September 16, 1997 NAAQS become effective

July 1, 1998 States submit Monitoring Plans

1998 – 2000 Monitors put in place nationwide

1998 – 2003 Monitoring data collected

1999 US EPA designates areas as “unclassifiable”

2000 US EPA completes five-year scientific review of NAAQS

2002 US EPA reviews PM2.5 NAAQS

2002 – 2005 US EPA designates non-attainment areas

2005 – 2008 States submit Implementation Plans for meeting the NAAQS

2012 – 2017 States have up to 10 years to meet NAAQS plus two one-year extensions

Limitations of the U.S. PMLimitations of the U.S. PM2.52.5

StandardsStandards• Causal relationships of PM2.5 to health not established;

only epidemiological relationships• 24-hour average masks peak exposures of shorter

duration• Highest concentrations neglected or attenuated by

statistical form

• Already regulated as a subset of existing PM10 standard

• Is not accurately measured by practical Federal Reference Methods (FRMs) under all circumstances

• Other indicators are more specific to respiratory and cardiovascular effects

(several of these are due to available measurement technology)

Why use 98Why use 98thth Percentile for Percentile for 24-hr NAAQS?24-hr NAAQS?

• Statistical robustness

• Statistically significant associations with health effects:

– Mortality

– Hospital Admissions

– Respiratory symptomsFrequency (%)

PM

2.5

FR

M M

ass

(g/

m3)

PM2.5 FRM Mass versus Frequency (%)Site 117 - El Paso Tillman (ELPATI, 481410002)

2000 - 2002

0.01

99.99

0.05 0.5

99.5

1

99

5

95

10

90

20

80

30

70

40

60

50

50

60

40

70

30

80

20

90

10

95

5

99

1

99.9

0.1

1

2

3

5

7

10

20

30

50

70

100

2006 versus 1997 PM2006 versus 1997 PM2.52.5 NAAQS NAAQS

• Same levels for primary (health) and secondary (welfare) standards

• Minor changes in ambient monitoring

• More stringent spatial averaging requirements

• More relaxed data completeness requirements

• Simplification of reporting requirements

PMPM2.52.5 Federal Reference Federal Reference

Methods (FRMs)Methods (FRMs)

Andersen RAASThermo Fisher Scientific, formerly Andersen Instruments, Smyrna, GA

URG MASSURG Corp., Raleigh, NC

Partisol SamplerThermo Fisher Scientific, formerly Rupprecht & Patashnick, Albany, NY

BGI PQ-200 BGI, Inc., Waltham, MA

PMPM2.52.5 Monitoring Changes Monitoring Changes

• Samplers with very sharp cut cyclones (VSCC) would be FRM (had been FEM)

• Requires improved impactor oil for WINS

• Time limit to recover samples increased from 96 to 177 hours

• Allows up to 30 days* to condition and weigh retrieved filters when transit temperature is less than average ambient temperature during sampling

*In the past, the number of days was determined by: days=34-T[°C]; T=storage temperature <25 °C

Size-selective InletsSize-selective Inlets

WINS Impactor Very sharp cut cyclone (VSSC)

PMPM2.52.5 Spatial Averaging Spatial Averaging

ChangesChanges**

• Current

– Correlation (r) ≥0.6 between monitor pairs

– Difference ≤20% between monitor values

• Proposed

– Correlation (r) ≥0.9 between monitor pairs

– Difference ≤10% between monitors

* Determined on a seasonal basis

PMPM2.52.5 Data Completeness Changes Data Completeness Changes

• Required ≥75% data completeness per quarter

• Collocated sampler data can substitute for missing primary sampler data

• Allow 11 or more samples per quarter if calculated annual standard design value exceeds the NAAQS

• For a quarter with < 11 samples, allow data substitution of an historically low 24-hr value (to reach 11 samples) if the results yield an annual mean, spatially averaged annual mean, and/or annual standard design value exceeding the NAAQS

PMPM2.52.5 Data Reporting Changes Data Reporting Changes

• No longer need to report the following parameters to EPA’s Air Quality System (AQS; http://www.epa.gov/ttn/airs/airsaqs/)– Flow rate– Coefficient of Variance– Sample volume– Minimum & maximum temperature– Minimum & maximum pressure

• Continue to report:– PM2.5 concentration

– Average temperature– Average pressure

• State and local agencies need to retain information on parameters no longer reported to AQS

Why a Proposed PMWhy a Proposed PM10-2.510-2.5

Standard?Standard?• Court decision (D.C. Circuit in 1999 and 2001)

– PM10 composed of PM2.5

– Need to regulate coarse PM independent of PM2.5

• Recent studies showing PM10-2.5 effects*

– Inflammation and aggravation of allergic effects

– Coughs in children

– Increased hospital admissions

*Generally stronger for short-term rather than long term effects

Limitations to the PMLimitations to the PM10-2.510-2.5

StandardStandard

• Includes any ambient mix of PM10-2.5 dominated by resuspended dust from high density traffic on paved roads and PM generated by industrial sources

• Excludes any ambient mix of PM10-2.5 dominated by rural dust and soils and PM generated by agricultural and mining sources

– Agricultural sources, mining sources and other similar crustal PM10-2.5-dominated sources shall not be subject to control in meeting this standard

Concerns about Proposed Concerns about Proposed Revisions to PM StandardsRevisions to PM Standards

• Are levels set to provide an adequate margin of safety to protect sensitive populations, given the quality of the measurement and health effects data?

• Should a separate short-term standard for PM2.5 be established based on visibility concerns?

• Do measurement, characterization, and health-effects studies adequately support the cited differences in toxicity between rural and urban dust?

• Why not control agricultural, mining and other non-urban dust sources?

For More Information:For More Information:

See the June issue of the Journal of the Air & Waste Management Association

for the “Critical Review” by

John Bachmann

“Will the Circle be Unbroken: A History of the U.S. National Ambient Air

Quality Standards.”