National Ambient Air Quality Standards and Implementation

National Tribal ForumJune 2011

What are NAAQS?• Title I of CAA directs EPA to establish National Ambient Air

Quality Standards (NAAQS) for commonly occurring air pollutants posing public health threats

• NAAQS set national levels for acceptable concentrations of specific pollutants in outdoor air known as “criteria pollutants”

• NAAQS consist of pollutant concentrations in air that may not be exceeded

• NAAQS are federal standards that apply coast-to-coast, regardless of jurisdiction

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National Ambient Air Quality Standards• Two types of standards are developed:

• “Primary” standards to protect public health with an adequate margin of safety

• “Secondary” standards to protect public welfare and the environment

• The CAA requires EPA to review the standard set for each criteria pollutant every 5 years with advice from the Clean Air Scientific Advisory Committee (CASAC)

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National Ambient Air Quality StandardsPollutant Primary Standards Averaging Time Secondary Standards

Carbon 9 ppm 8-hour None Monoxide (10 mg/m3)   35 ppm 1-hour   (40 mg/m3)Lead

0.15 µg/m3 Rolling 3-Month Average Same as Primary

Nitrogen 53 ppb

AnnualSame as PrimaryDioxide (Arithmetic Average)

  100 ppb 1-hour None Particulate

150 µg/m3 24-hour Same as PrimaryMatter (PM10)

Particulate 15.0 µg/m3

AnnualSame as PrimaryMatter (PM2.5) (Arithmetic Average)

 35 µg/m3 24-hour Same as Primary

Ozone 0.075 ppm 8-hour Same as Primary (2008 std) 0.08 ppm 8-hour Same as Primary (1997 std)

Sulfur 0.03 ppm Annual 0.5 ppm 3-hour Dioxide (Arithmetic Average)   0.14 ppm 24-hour  75 ppb 1-hour None

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Current Schedule for Ongoing NAAQS Reviews (March 2011)

MILESTONE

POLLUTANT

NO2 Primary SO2 Primary Ozone Reconsideration CO PM

NO2/SO2 Secondary

Lead

NPR Jun 26, 2009 Nov 16, 2009 Jan 6, 2010 Jan 28, 2011 Late 2011 July 12, 2011 Nov 2013

NFR Jan 22, 2010 Jun 2, 2010 July 29, 2011 Aug 12, 2011 TBD Mar 20, 2012 Sept 2014

NOTE:

Underlined dates indicate court-ordered or settlement agreement deadlines

Next Ozone Review: Proposal in Jun 2013 and Final in Mar 2014

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PM NAAQS Review

PM NAAQS Review Process to Date• Current review initiated in 2007; includes review of primary (health-based) and secondary

(welfare-based) standards for fine and coarse particles

• Review is thorough and extensive, with many opportunities for CASAC and public comment; final documents take into consideration CASAC and public comments on multiple draft documents• Integrated Science Assessment: final document issued December 2009

• Synthesis and assessment of most policy-relevant science

• Risk/Exposure Assessments: final documents issued June/July 2010• Quantitative Health Risk Assessment; Urban-Focused Visibility Assessment• Focus on fine particles and did not assess risks associated with coarse particles

• Policy Assessment: final document issued April 2011• Staff conclusions address adequacy of current standards and potential alternative standards appropriate

to consider• Discusses broadest range of policy options supported by the available scientific evidence, quantitative

assessments, and air quality analyses

• All documents available at: http://www.epa.gov/ttn/naaqs/standards/pm/s_pm_index.html 7

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Final Policy Assessment Conclusions and CASAC Advice Primary (health-based) PM2.5 Standards• Staff and CASAC conclude it is appropriate to consider revising the standards to provide increased public health

protection• Consider revising annual standard level within a range of 13-11 µg/m3 (current standard is 15 µg/m3)

• Staff concludes that evidence most strongly supports range of 12 -11 µg/m3

• Consider retaining or revising 24-hour standard level within a range of 35-30 µg/m3 (current standard is 35 µg/m3)

Primary (health-based) PM10 standards• Staff concludes scientific evidence and associated uncertainties could provide support for either retaining or revising the

current primary 24-hour PM10 standard• To the extent consideration is given to revising the standard, staff concludes it would be appropriate to consider a 98 th percentile form in

conjunction with a level within a range of 85 to 65 µg/m3

• CASAC does not support retaining the current PM10 standard; recommends revising form and level in order to increase public health protection

• CASAC recommends a 98th percentile form in conjunction with a level within a range of 75 to 65 µg/m 3

Secondary (welfare-based) PM standards• Staff and CASAC agree that it is appropriate to consider setting a distinct secondary PM2.5 standard to address visibility

impairment primarily in urban areas; considering options for structuring such a secondary standard distinct from the primary PM2.5 standards, in terms of:

• Alternative indicators, averaging times, and forms• Selecting alternative standard levels that reflect appropriate degree of public welfare protection

No decisions have been made at this time• EPA anticipates issuing a proposal for public review and comment later this year

Review of the Secondary NAAQS for Oxides of Nitrogen and Sulfur

Overview• Existing secondary NAAQS (for environmental effects):

• For NO2: 0.053 ppm (parts per million) averaged over a year; and• For SO2: 0.5 ppm averaged over three hours, not to be exceeded more than once per year

• In this review, for the first time, EPA is reviewing the environmental impacts of pollutants separately from the health-based impacts, and considering the effects of multiple pollutants simultaneously. Specifically, EPA’s Integrated Science Assessment covers:

• Oxides of nitrogen (N) and sulfur (S) -- the “criteria pollutants” :• SO2 and NO2 – indicators for current secondary standard• Particulate sulfate, SO4, combined with SO2 is defined as SOx• NOy – includes the transformation products from emissions of oxides of nitrogen (e.g., nitric acid

and particulate nitrate)

• Forms of N which are not criteria pollutants, but that contribute to N deposition, include:• Ammonia gas, NH3

• Ammonium ion, NH4

• EPA is under a court-ordered schedule to sign a proposed rule by July 12, 2011

Together referred to as reduced nitrogen, NHx

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Key Issues• Existing secondary standards protect against direct effects of gaseous NO2 and SO2 on vegetation

• In addition to affecting plants, oxides of nitrogen and sulfur are associated with an array of deposition-related effects, including nutrient enrichment and aquatic acidification

• When deposited on land and in lakes and streams, oxides of nitrogen and sulfur affect soils, water quality, and fish and wildlife

• In this review, the EPA has been exploring the possibility of developing a multi-pollutant standard to address deposition-related effects, particularly aquatic acidification

• Because different ecosystems vary in the amount of acid deposition they can tolerate, the EPA staff has been working to develop a formula called the “Aquatic Acidification Index” (AAI) that could be used to relate ambient levels of oxides of nitrogen and sulfur to water quality

• The terms of the equation need to be quantified on an area-specific basis, because ecosystem sensitivity varies across the nation due to variable geologic, hydrologic, and environmental factors

• The significant challenge is to translate spatially variable effects into a national standard, including limitations on available monitoring data

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Conceptual Model of an Aquatic Acidification Standard

• Aquatic effects are not directly related to concentrations of oxides of N and S in the ambient air– major difference from other NAAQS standards

• Linkage between ecological effects and deposition of oxides of N and S is characterized by critical load modeling

• Linkage between deposition and air concentrations of oxides of N and S is characterized by atmospheric modeling that translates emissions of N and S into estimates of both ambient concentrations and related deposition

• Model also takes into account deposition of N from reduced forms of nitrogen (e.g., ammonia) that contribute to the aquatic effects but are not part of the “criteria” pollutants addressed by this standard

Ecological effects and ecological indicator (Acid

Neutralizing Capacity, ANC)

Linking atmosphericdeposition to ecological

indicator

Linking deposition to “allowable” concentrations of oxides of N and

S in ambient air

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• Omernik Ecoregion III classification scheme (developed in the 1980s by EPA) divides the continental U.S. into 84 ecologically relevant regions, based on common vegetation, geology, soils, and hydrological characteristics

• A multi-pollutant standard for oxides of nitrogen and sulfur must account for these differences to provide appropriate degree of protection against aquatic acidification in different regions

• Remaining complexities and uncertainties will be challenging to address

Illustrating the Complexity: Significant Variation Among Ecoregions

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Acid Sensitive and Non-Sensitive Ecoregions

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• Categorization based on water quality data and land use categories (naturally acidic and managed areas categorized as relatively non-sensitive)

• Ecosystem sensitivity varies across the nation, predominantly due to variability of geologic material (bedrock and soils) which buffers acidifying deposition

NAAQS Implementation

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PollutantNAAQS

Promulgation Date

DesignationsEffective

110(a) SIPs due

(3 yrs after NAAQS promulgation)

Attainment Demonstration

DueAttainment

Date

PM2.5 (2006) Sept 2006 Dec 2009 Sept 2009 Dec 2012 Dec

2014/2019

Pb Oct 2008Dec 2010/2011(extra time for new

monitors)Oct 2011 June

2012/2013Dec

2015/2016

NO2 (primary) Jan 2010 Feb 2012 Jan 2013 Aug 2013 Feb 2017

SO2 (primary) June 2010 July 2012 June 2013 Jan 2014 July 2017

Ozone July 2011 No later than Summer 2013 July 2014 No later than

Summer 2016No later

than 2019(moderate)

CO Aug 2011 Sept 2013 Aug 2014 Sept 2015 Sept 2018PM2.5 (2012) TBD

NO2/SO2 Secondary Mar 2012 April 2014 Mar 2015 Oct 2015 NA

Anticipated NAAQS 110 SIP Implementation MilestonesUpdated April 2011

Ozone Implementation Rules• Revisions to implementation rule for 1997 8-hr ozone NAAQS• Draft 2011 ozone NAAQS implementation rule will address:

• Proposed approaches to classifying ozone nonattainment areas• Air quality thresholds for Marginal, Moderate, Serious, Severe, and Extreme• Impact of options will be illustrated using 2008-2010 air quality data

• Attainment deadlines for each classification

• State Implementation Plan (SIP) schedule and requirements for primary standard nonattainment areas

• Planning and control requirements currently required for the 1997 NAAQS that must continue to be implemented (i.e., “anti-backsliding” requirements)

• Implementation approach for first-ever separate secondary standard, including classifications and SIP requirements

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PM 2.5 Implementation • SIP timeline

• For the 2006 standards• Designations occurred in Dec. 2009, and SIPs are due Dec. 2012

• For the 2012 standards (assume promulgation in 2012)• Designations would be in 2014, and SIPs would be due in 2017

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Implementation Guidance for 2006 PM2.5 Standards

• Framework of existing implementation rule is appropriate for attainment planning for 2006 PM2.5 standards. Guidance memo (not rule revision) on key issues under development. • Interpretation of existing rule as applied to 2006 standards• Attainment within 5 years based on 2012-2014 air quality data• RFP policy revision: no credit for reductions outside the NA• RFP milestone years if attainment date beyond 5 years: 2014, 2017• Reminder that PM2.5 attainment planning and control strategies must account for

condensable PM2.5 emissions. • Significant local health benefits from direct PM2.5 reductions

• Issued “Strategies for Reducing Residential Wood Smoke” (Oct. 2009)• www.epa.gov/ttncaaa1t1/memoranda/strategies-doc-8-11-09.pdf

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Redesignation Requests• 1997 8-hr Ozone NAAQS

• Moderate area requests (June 2011 attainment deadline extensions) are pending for RACT updates of 2006-2007 CTG revisions

• Baton Rouge Area, LA; Chicago-Gary-Lake County Area, IL; Milwaukee-Racine Area, WI; Sheboygan Area, WI; St. Louis Area, IL; Phoenix-Mesa Area, AZ (Former Subpart 1)

• 1997 PM2.5 NAAQS• Most are pending final Transport Rule

• Chicago-Gary-Lake County, IN; Cincinnati-Hamilton, KY; Evansville, IN; Greensboro-Winston Salem-High Point, NC; Hickory-Morganton-Lenoir, NC; Birmingham, AL (also 2006 PM2.5 NAAQS)

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CO NAAQS Review• Proposed to retain current standard on January 28, 2011

• Public health and environmental organizations in NESCAUM support revision• Industry and 4 state agencies support retention

• Proposed ambient air monitoring requirements to co-locate CO monitors with “near-road” NO2 monitors in urban areas having populations of 1 million or more• Approximately 77 CO monitors within 53 urban areas, as part of the overall CO monitoring

network• NACAA, NESCAUM, NYSDEC, and public health and environmental groups support new

requirements, but states want population threshold raised to 2.5 million• Many also concerned about losing Neighborhood monitors

• Industry and several state and local governments do not support near-road monitoring

• There are currently no CO nonattainment areas for existing standards (9 ppm 8-hr, 35 ppm 1-hr)

• Final rule due by August 12, 2011 21

Exceptional Events Guidance• Flagging Monitoring Data for exclusion for determining nonattainment• Draft Guidance Products Available Now

• Overview of draft guidance and 2 attachments• Frequently asked questions (~30 pages)• High Winds Guidance Document (~60 pages)

• Deadline for comments is 6/30/11; will work with state/local/tribal stakeholders in developing solutions to identified issues

• Finalize guidance in November after broader outreach and comment (longer timeframe if rule revisions are pursued)

• Website with example demonstration submittals at http://www.epa.gov/ttn/analysis/exevents.htm

• Draft Guidance Products Under Development• Guidance document on wildfire events and ozone – summer 2011 draft for review• Replacement for EPA’s Interim Fire Policy

• Currently reconsidering the purpose and approach in light of interagency review comments.• Anticipate components to clarify treatment of agricultural burning and better define “basic smoke management

practices”• Will then meet with states and federal agencies to discuss concepts before issuing new draft for public comment22

Pb Designations• The final Pb NAAQS was signed on October 15, 2008.• Guidance was published in the Federal Register as part of the Pb NAAQS revision on

November 12, 2008• Pb designations is occurring in two rounds:

• The first round of designations was signed on November 16, 2010. • Designated 16 areas as nonattainment.• Deferred designations for all other areas to the second round.

• Statutory deadline for the second round of designations is October 14, 2011.• 120-day letters are due June 15, 2011. • Anticipating designating 5 areas as nonattainment.• Remaining areas will be designated as unclassifiable/attainment.

• No tribal areas were designated nonattainment in the first round, and we don't expect any areas to be designated nonattainment in the second round.

• Under section 110 of the Clean Air Act, all states (including those without any nonattainment areas) are required to submit infrastructure SIPs by October 15, 2011

• Among the requirements for an infrastructure SIP is a permit program implementing PSD and nonattainment NSR.

• Attainment Demonstrations SIPs, for round one, are due June 30, 2012. For the second round, attainment SIPS are expected to be due June 30, 2013

• The attainment date for the first round is December 31, 2015, and the attainment date for the second round is expected to be December 31, 2016

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Ozone Designations• EPA is reconsidering the 2008 ozone NAAQS.

• Proposed more protective standards in January 2010• Final decision expected by end of July 2011

• New NAAQS established as a result of the reconsideration would replace the 2008 ozone NAAQS. EPA does not intend to implement the 2008 NAAQS

• Final NAAQS rule will provide schedule for designating areas for 2011 ozone NAAQS, including deadline for submitting area designation recommendations

• EPA will be providing guidance and training to help tribes participate in the designations process

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PSD Revisions for Part 52.21(u)• Working on a rule to remove the preclusion of tribes taking delegation

of the PSD program• Proposal in September 2011• Final in January 2012

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For More Information • Contact

• Laura McKelvey• Mckelvey.laura@epa.gov• 919-541-5497

• Angel McCormack• Mccormack.angel@epa.gov • 919-541-3588

• Visit the NAAQS website• http://www.epa.gov/ttnnaaqs

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