National Ambient Air Quality
Standards and Implementation
National Tribal Forum
June 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 Standards
Pollutant
Carbon
Monoxide
Primary Standards Averaging Time
9 ppm
3
(10 mg/m )
35 ppm
3
(40 mg/m )
Lead
0.15 µg/m
Nitrogen
Dioxide
53 ppb
100 ppb
Particulate
Matter (PM10)
150 µg/m
Particulate
Matter (PM2.5)
15.0 µg/m
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Ozone
Sulfur
Dioxide
3
3
3
35 µg/m
0.075 ppm
(2008 std)
0.08 ppm
(1997 std)
0.03 ppm
0.14 ppm
75 ppb
Secondary Standards
8-hour
None
1-hour
Rolling 3-Month
Average
Annual
(Arithmetic Average)
1-hour
Same as Primary
Same as Primary
None
24-hour
Same as Primary
Annual
(Arithmetic Average)
Same as Primary
24-hour
8-hour
Same as Primary
Same as Primary
8-hour
Same as Primary
Annual
(Arithmetic Average)
24-hour
1-hour
0.5 ppm
3-hour
None
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Current Schedule for Ongoing
NAAQS Reviews (March 2011)
POLLUTANT
MILESTONE
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
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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 98th
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/m3
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
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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
Together referred to as reduced nitrogen, NHx
• Ammonium ion, NH4
• EPA is under a court-ordered schedule to sign a proposed rule by July 12, 2011
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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
Ecological effects and
ecological indicator (Acid
Neutralizing Capacity, ANC)
Linking atmospheric
deposition to ecological
indicator
Linking deposition to “allowable”
concentrations of oxides of N and
S in ambient air
• 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
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Illustrating the Complexity: Significant Variation Among Ecoregions
• 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
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Acid Sensitive and Non-Sensitive Ecoregions
• 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
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NAAQS Implementation
Anticipated NAAQS 110 SIP Implementation Milestones
Updated April 2011
Pollutant
PM2.5
(2006)
NAAQS
Promulgation
Date
Designations
Effective
Sept 2006
Dec 2009
110(a) SIPs
due
(3 yrs after NAAQS
promulgation)
Attainment
Demonstration
Due
Attainment
Date
Sept 2009
Dec 2012
Dec
2014/2019
Oct 2011
June
2012/2013
Dec
2015/2016
Dec 2010/2011
Pb
Oct 2008
NO2
(primary)
Jan 2010
Feb 2012
Jan 2013
Aug 2013
Feb 2017
SO2
(primary)
June 2010
July 2012
June 2013
Jan 2014
July 2017
July 2011
No later than
Summer 2013
July 2014
No later than
Summer 2016
Sept 2013
Aug 2014
Sept 2015
Sept 2018
April 2014
Mar 2015
Oct 2015
NA
Ozone
CO
PM2.5
(2012)
NO2/SO2
Secondary
Aug 2011
(extra time for new
monitors)
No later
than 2019
(moderate)
TBD
Mar 2012
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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 “nearroad” 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
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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
comment
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•
•
•
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.
•
•
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
•
•
•
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.
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
• [email protected]
• 919-541-5497
• Angel McCormack
• [email protected]
• 919-541-3588
• Visit the NAAQS website
• http://www.epa.gov/ttnnaaqs
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