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Update on National Ambient Air Quality Standards (NAAQS)

Update on National Ambient Air Quality Standards (NAAQS). National Air Quality Conference March 16, 2010 Lydia Wegman US Environmental Protection Agency Office of Air Quality Planning and Standards. Current NAAQS Review Process.

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Update on National Ambient Air Quality Standards (NAAQS)

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  1. Update on National Ambient Air Quality Standards (NAAQS) National Air Quality Conference March 16, 2010 Lydia Wegman US Environmental Protection Agency Office of Air Quality Planning and Standards

  2. Current NAAQS Review Process Integrated Science Assessment: concise evaluation and synthesis of most policy-relevant studies Peer-reviewed scientific studies Integrated Review Plan timeline and key policy-relevant scientific questions Policy Assessment staff analysis of policy options based on integration and interpretation of information in ISA and REA Workshop on science-policy issues CASAC review and public comment Risk/Exposure Assessment: concise quantitative assessment focused on key results, observations and uncertainties CASAC review and public comment Agency decision- making and draft proposal notice EPA proposed decision on standards Interagency review EPA final decision on standards Public hearings and comments on proposal Agency decision- making and draft final notice Interagency review

  3. NAAQS in 2010 • NO2 – Final in Jan 2010 • SO2 – Final in June 2010 • O3 Reconsideration – Final in Aug 2010 • CO – Proposal in Oct 2010 • PM – Proposal in Nov 2010

  4. Current Schedule for Ongoing NAAQS Reviews NOTE: Underlined dates indicate court-ordered or settlement agreement deadlines Next Ozone Review: Proposal in May 2013 and Final in Feb 2014

  5. NO2 NAAQS • On January 22, 2010 EPA strengthened the primary national ambient air quality standard (NAAQS) for nitrogen dioxide (NO2) to increase protection of public health by: • adding a 1-hour NO2 standard at 100 parts per billion (ppb); and • retaining the annual average NO2 standard at a level of 53 ppb • Revised NO2 standard reflects the maximum allowable NO2 concentrations anywhere in an area. • In many locations, these maximum concentrations are likely to occur around roads • Some monitors will be located to focus on vulnerable and susceptible groups Under a separate review, EPA is considering the need for changes to the secondary NO2 standard • For more information go to http://www.epa.gov/air/nitrogenoxides

  6. Sources of NOx Pollution Industrial/commercial/residential combustion (12%) Utilities (22%) Other (8%) Mobile Sources (58%) Based on 2002 National Emissions Inventory data

  7. NO2 NAAQS Implementation Schedule

  8. SO2 NAAQS • November 16, 2009: EPA proposed to strengthen primary standards for sulfur dioxide (SO2) to improve public health protection • EPA proposed: • A new 1-hour SO2 standard to better protect public health by reducing people’s exposure to high short-term concentrations of SO2 • Level between 50 - 100 ppb • Would replace annual and 24-hour primary SO2 standards • Current standards were established in 1971 • In the last review of the SO2 standards, completed in 1996, EPA considered, but did not set, a 5-minute primary standard to protect asthmatics • In 1998, the U.S. Court of Appeals for the District of Columbia Circuit remanded this decision back to EPA for further explanation • Evaluation of scientific evidence indicates that a 1-hr standard would better protect public health by reducing people’s exposure to high short term concentrations of SO2 • EPA’s proposal is consistent with the recommendations of the Clean Air Scientific Advisory Committee • The final rule will be signed no later than June 2, 2010 • EPA is reviewing secondary SO2 standard separately • Part of a joint review with NO2 secondary standards -- to be completed in 2012 • For more information, go to http://www.epa.gov/air/urbanair/so2

  9. Sources of SO2 Pollution • Fossil fuel combustion at power plants (66%) and other industrial facilities (29%) are the main sources of SO2 emissions • Other sources include industrial processes such as extracting metal from ore, and the burning of high sulfur fuels by locomotives, large ships, and non-road equipment

  10. SO2 NAAQS Implementation Timeline

  11. CO NAAQS • Proposal Oct 28, 2010 • Final May 13, 2011 • March 22-23 CASAC review of the 2nd draft Risk and Exposure Assessment and draft Policy Assessment

  12. Ozone NAAQS Reconsideration • Proposal signedon January 6, 2010. • Public comment period of 60 days closes on March 22, 2010 • 3 Public hearings • Final Rule to be signed by August 31, 2010.

  13. Reconsidering the Ground-Level Ozone Standards • The proposal reconsiders the 2008 decision on the ground-level ozone standards based on the scientific and technical record used in the March 2008 review, which included more than 1,700 scientific studies. • In this reconsideration, EPA is not relying on studies about the health and ecological effects of ozone that have been published since the science assessment to support the 2008 review was completed in 2006. However, EPA’s Office of Research and Development conducted a provisional assessment of these newer studies and found they do not materially change the conclusions of the Agency's earlier science assessment. • The proposed range is within the range recommended by CASAC. • The ozone standards set in 2008 were not as protective as recommended by EPA’s panel of science advisors, the Clean Air Scientific Advisory Committee (CASAC).

  14. Ozone Health Impacts: “ Pyramid of Effects” • At-risk groups include: • People with lung disease such as asthma or chronic obstructive pulmonary disease (COPD). • Children. • Older adults. • People who are more likely to be exposed, such as people who are active outdoors, including children and outdoor workers. Severity of Effects Proportion of Population Affected

  15. Ozone and the Environment • Ground-level ozone is absorbed by the leaves of plants, where it can: • Interfere with the ability of sensitive plants to produce and store food. • This can lead to reduced growth, biomass production and yields. • Make sensitive plants more susceptible to certain diseases, insects, harsh weather, other pollutants, and competition. • Reduce or change plant species diversity in associated ecosystems. • This can lead to damage to ecosystems dependent on those species. • Visibly injure the leaves of plants, affecting the appearance of vegetation in national parks, recreation areas and cities.

  16. Proposed Revisions to Primary Ozone Standard • EPA is proposing to strengthen the level of the 8-hour primary ozone standard to a level within the range of 0.060-0.070 parts per million (ppm). • The proposal to set a primary standard within this range places additional weight on key pieces of scientific evidence, including: • evidence from clinical studies showing effects in healthy adults at 0.060 ppm, including decreased lung function and respiratory symptoms; • evidence from clinical and epidemiological studies indicating that people with asthma are likely to experience larger and more serious effects than healthy people; • epidemiological evidence indicating associations for a wide range of serious health effects, including respiratory-related emergency department visits and hospital admissions and risk of premature mortality, that extend below the current standard level of 0.075 ppm; and • estimates from the risk and exposure assessment indicating that important improvements in public health could be achieved by a standard more stringent than 0.075 ppm.

  17. Proposed Revisions to Secondary Ozone Standard • The proposed secondary standard, called W126, is designed to account for the cumulative effects of repeated ozone exposures on sensitive vegetation during the three months of the year when ozone concentrations are highest • EPA is proposing a cumulative, seasonal secondary standard at a level in the range of 7-15 ppm-hours. • This cumulative standard would add weighted hourly ozone concentrations across all days in a three-month period. • The Administrator proposed that a seasonal secondary standard identical to the primary standard, as was set in 2008, is inadequate to provide the requisite level of protection for vegetation and ecosystems. • More details about the W126 standard in next slide and at breakout session on Communicating the NAAQS Revisions – Roundtable Discussion

  18. Understanding the W126 Proposed Secondary Standard • Steps in calculating W126 value for a particular site: • Measure hourly ozone (O3) concentrations for each hour within the 12 hour daylight period (8am-8pm). • Assign a weight to each hourly value based on concentration: lower concentrations receive less weight than higher concentrations. • Sum the 12 weighted hourly values to calculate a daily W126 value. • Repeat steps 1-3 for each day within the ozone season and then sum the daily values to calculate the monthly W126 value. • Identify the consecutive 3-month period whose monthly W126 values produce the highest total. This total becomes the seasonal W126 for this site. • Average three years of maximum W126 values and compare to standard. weight Example of weighting over 5-hour period: Daily value = Sum of values over 12 daylight hours

  19. Implementation Considerations For Proposed Ozone Standards • Designations • EPA proposed an accelerated schedule for designating areas for the primary ozone standard. • EPA is taking comment on whether to designate areas for a seasonal secondary standard on an accelerated schedule or a 2-year schedule. • EPA is reviewing existing designations guidance and will be communicating with States and Tribes if additional guidance is needed. • Previous Ozone Standards • The 2008 8-hour ozone NAAQS and the 1997 8-hour ozone NAAQS remain in place. • Implementation for the 2008 8-hour ozone NAAQS is delayed during the reconsideration. • EPA has extended the deadline for area designations for the 2008 ozone standards by one year (until 2011). • Any new ozone standards would replace the 2008 ozone standards. Implementation requirements for the 2008 ozone standards, including designations, would no longer apply. • The 1997 NAAQS remain in effect and implementation of that standard should continue.

  20. Proposed Accelerated Implementation Timeline • EPA is planning to propose an implementation rule in spring 2010 and issue a final rule as quickly as possible after the final ozone NAAQS.

  21. Estimated Number of Adverse Health Effects Avoided under Alternate Standard Levels in 2020* *Includes benefits of reduced fine particle concentrations associated with illustrative ozone controls applied to meet a primary ozone standard in the proposed range

  22. 322 of 6751 monitored counties violate the standard Counties With Monitors Violating the March 2008 Ground-Level Ozone Standards 0.075 parts per million(Based on 2006 – 2008 Air Quality Data) • Notes: • Counties with at least one monitor with complete data for 2006 – 2008 • To determine compliance with the March 2008 ozone standards, the 3-year average is truncated to three decimal places.

  23. 515 counties violate 0.070 ppm 93 additional counties violate 0.065 ppm for a total of 608 42 additional counties violate 0.060 ppm for a total of 650 Counties With Monitors Violating Proposed Primary 8-hour Ground-level Ozone Standards 0.060 - 0.070 parts per million (Based on 2006 – 2008 Air Quality Data) EPA will not designate areas as nonattainment on these data, but likely on 2008 – 2010 data which are expected to show improved air quality. Notes: 1. No monitored counties outside the continental U.S. violate. 2. EPA is proposing to determine compliance with a revised primary ozone standard by rounding the 3-year average to three decimal places.

  24. 196 counties violate 15 ppm-hours 383 additional counties violate 7 ppm-hours for a total of 579 Counties With Monitors Violating Proposed Secondary Seasonal Ground-Level Ozone Standards 7 – 15 parts per million – hours (Based on 2006 – 2008 Air Quality Data) EPA will not designate areas as nonattainment on these data, but likely on 2008 – 2010 data which are expected to show improved air quality. No monitored counties outside the continental U.S. violate.

  25. 99 counties projected to violate 0.070 ppm 149 additional counties projected to violate 0.065 ppm for a total of 248 203 additional counties projected to violate 0.060 ppm for a total of 451 Counties With Monitors Projected to Violate the Proposed Primary 8-hour Ground-Level Ozone Standards in 2020 0.060 - 0.070 parts per million • Notes: • The modeled emissions in 2020 reflect the expected emissions reductions from federal programs by 2020 including: the Clean Air Interstate Rule, the Clean Air Mercury Rule, the Clean Air Visibility Rule, the Clean Air Nonroad Diesel Rule, the Light-Duty Vehicle Tier 2 Rule, the Heavy Duty Diesel Rule, the proposed rules for Locomotive and Marine Vessels and for Small Spark-Ignition Engines, and an estimate of State-level mobile and stationary source controls that were projected to be needed to attain pre-existing PM 2.5 and ozone standards. • Controls applied are illustrative. States may choose to apply different control strategies for implementation. • EPA did not model future violations outside the continental U.S. • EPA is proposing to determine compliance with a revised primary ozone standard by rounding the 3-year average to three decimal places.

  26. Counties With Monitors Projected to Violate the Proposed Secondary Seasonal Ground-level Ozone Standards in 2020 7 – 15 parts per million - hours 27 counties violate 15 ppm-hours 167 additional counties violate 7 ppm-hours for a total of 194 • Notes: • The modeled emissions in 2020 reflect the expected emissions reductions from federal programs by 2020 including: the Clean Air Interstate Rule, the Clean Air Mercury Rule, the Clean Air Visibility Rule, the Clean Air Nonroad Diesel Rule, the Light-Duty Vehicle Tier 2 Rule, the Heavy Duty Diesel Rule, the proposed rules for Locomotive and Marine Vessels and for Small Spark-Ignition Engines, and an estimate of State-level mobile and stationary source controls that were projected to be needed to attain pre-existing PM 2.5 and ozone standards. • Controls applied are illustrative. States may choose to apply different control strategies for implementation. • EPA did not model future violations outside the continental U.S.

  27. PM NAAQS 2006 • Revised 24-hour PM2.5 standard by lowering level from 65 to 35 µg/m3 • Retained annual PM2.5 standard at 15 µg/m3 • Retained 24-hour PM10 standard to address coarse particles (PM10-2.5) • Continued to set secondary standards identical to primary standards • Did not adjust the PM AQI, intended to issue a separate rule • Following final rule, CASAC expressed serious concerns with decisions that were not consistent with CASAC advice

  28. Remand of Primary and Secondary Annual PM2.5 Standard • In Feb 2009, D.C. Circuit Court remanded some portions of the final rule • Court concluded EPA failed to adequately explain why annual standard is sufficient to protect public health with an adequate margin of safety • Annual primary standard remanded for further consideration of whether it provides an adequate margin of safety from the risk of short-term exposure to PM2.5, and whether it provides an adequate margin of safety against morbidity in children and other vulnerable subpopulations • Court concluded decision to set secondary standards identical to primary standards was unreasonable and contrary to the law • Secondary standards remanded for reconsideration

  29. PM NAAQS Review • Integrated Science Assessment • Finalized December 2009 • Risk and Exposure Assessments • Second draft assessment documents (quantitative health risk assessment and urban-focused visibility assessment) released for CASAC and public review on March 10-11 • Policy Assessment • First draft released for CASAC and public review in March 2010 • Will discuss CASAC comments at teleconference scheduled for April 8 • Proposed rulemaking – November 2010 • Final rulemaking – July 2011 • For more information: http://www.epa.gov/ttn/naaqs/standards/pm/s_pm_index.html

  30. Key Issues for Primary and Secondary Standards • Extensive new health evidence available on PM2.5, including epidemiological studies of short- and long-term exposures • To what extent are associations causally related to PM? • For PM2.5, ISA infers associations are causalfor short- and long-term exposures and cardiovascular effects and mortality; likely causalfor respiratory effects; and suggestive for cancer, developmental effects • For PM10-2.5, associations for short-term exposures are suggestive for cardiovascular and respiratory effects and mortality • For UFPs, associations for short-term exposures are suggestivefor cardiovascular and respiratory effects • To what extent do reported associations extend to air quality levels lower than had previously been observed or that are observed in areas that would meet the current suite of PM2.5 standards? • Associations extend to lower concentrations than observed in previous review • Include consideration of impacts on at-risk populations • To what extent are associations due to specific components or sources? • Emerging information on relative toxicity of some components or sources, but evidence insufficient to infer causality • Focus on urban visibility for secondary standards • Assessment of different indicators of PM pollution that are more directly related to visibility impairment as basis for distinct secondary standard

  31. PM2.5 AQI • EPA plans to propose revisions to the AQI when we issue a PM NAAQS proposal (currently slated for November) • In the interim, we are using 35 µg/m3 as the AQI value of 100 (the breakpoint between codes yellow and orange) • We have made this change on the AIRNow Web site • Guidance issued in Sept 2009 recommended that States consider using alert, warning, emergency and significant harm levels consistent with the AQI levels presented in the February 2007 issue paper • AQI 200 = Alert Level = 140.5 - 210.4 µg/m3 • AQI 300 = Warning Level = 210.5 – 280.4 µg/m3 • AQI 400 = Emergency Level = 280.5 – 350.4 µg/m3 • AQI 500 = Significant Harm Level (SHL) = 350.5 µg/m3 • For those with authority to do so, EPA will accept the use of AQI breakpoints that are consistent this guidance

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