1

Update on National Ambient Air Quality Standards (NAAQS)

National Air Quality Conference March 16, 2010

Lydia WegmanUS Environmental Protection Agency

Office of Air Quality Planning and Standards

2

Integrated Review Plan

timeline and key policy-relevant

scientific questions

Integrated Science Assessment: concise evaluation and synthesis of

most policy-relevant studies

Risk/Exposure Assessment: concise quantitative assessment

focused on key results, observations and uncertainties

Workshop on science-policy

issues

Public hearings and comments

on proposal

EPA final decision

on standards

Interagency review

Interagency review

Agency decision- making and draft proposal notice

Agency decision- making and draft

final notice

CASAC review and public comment

CASAC review and public comment

Policy Assessment

staff analysis of policy options based on integration and interpretation of

information in ISA and REA

EPA proposed decision on standards

Peer-reviewed scientific studies

Current NAAQS Review Process

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

MILESTONE

POLLUTANT

Lead NO2 Primary SO2 Primary Ozone Reconsideration

CO PMNO2/SO2

Secondary

NPR

New schedule

being developed

Jun 26, 2009 Nov 16, 2009 Jan 6, 2010Oct 28,

2010Nov 2010 July 12, 2011

NFR Oct 15, 2008 Jan 22, 2010 Jun 2, 2010 Aug 31, 2010May 13,

2011July 2011 Mar 20, 2012

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

Utilities (22%)

Mobile Sources (58%)

Other (8%)

Industrial/commercial/residential combustion (12%)

Sources of NOx Pollution

Based on 2002 National Emissions Inventory data

7

NO2 NAAQS Implementation ScheduleMilestone Date

State Designation

Recommendations to EPAJanuary 2011: One year following promulgation (Based on existing network data)

DesignationsJanuary 2012: EPA designates all/most areas as “unclassifiable” (because near road monitors not in place)

New NO2 Monitoring Network

January 1, 2013: All monitors operating

Next NO2 NAAQS Review Completed

January 2015: Anticipated time frame

Nonattainment Re- Designations

(discretionary)

January 2016/2017 (depending on date that sites become operational)

Attainment DateJanuary 2021/2022 (5 years after date of nonattainment designations)

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

Milestone Date

Signature – Final Rule June 2, 2010

State Designation Recommendations to EPA

June 2011

Final Designations June 2012

SIPs Due Winter 2014

Attainment Date Summer 2017

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 signed on 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

• 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).

Reconsidering the Ground-Level Ozone Standards

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.

Proportion of Population AffectedProportion of Population Affected

Severity of Effects

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

• 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.

Proposed Revisions to Primary Ozone Standard

17

• 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

Proposed Revisions to Secondary Ozone Standard

18

Daily value = Sum of values over 12 daylight hours

Steps in calculating W126 value for a particular site:

1. Measure hourly ozone (O3) concentrations for each hour within the 12 hour daylight period (8am-8pm).

2. Assign a weight to each hourly value based on concentration: lower concentrations receive less weight than higher concentrations.

3. Sum the 12 weighted hourly values to calculate a daily W126 value.

4. Repeat steps 1-3 for each day within the ozone season and then sum the daily values to calculate the monthly W126 value.

5. Identify the consecutive 3-month period whose monthly W126 values produce the highest total. This total becomes the seasonal W126 for this site.

6. Average three years of maximum W126 values and compare to standard.

Hourly O3

(ppm)

Weight W126(ppm-hrs)

0.03 0.01 0.00

0.05 0.11 0.01

0.06 0.30 0.02

0.08 0.84 0.07

0.10 1.0 0.10

SUM: 0.20w

eig

ht

Understanding the W126 Proposed Secondary Standard

Example of weighting over 5-hour period:

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

Milestone Date

Signature—Final Rule August 31, 2010

State Designation

Recommendations to EPA

January 2011

Final Designations Effective no later than August 2011

Attainment Demonstration SIPs Due

December 2013

Attainment Dates 2014-2031 (depends on severity of problem)

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*

0.070 parts per million 0.060 parts per million

Chronic bronchitis 880 2,200

Nonfatal heart attacks 2,200 5,300

Hospital and emergency room visits 6,700 21,000

Acute bronchitis 2,100 5,300

Upper and lower respiratory symptoms 44,000 111,000

Aggravated asthma 23,000 58,000

Days when people miss work or school 770,000 2.5 million

Days when people must restrict their activities

2.6 million 8.1 million

Avoided premature mortality 1,500 to 4,300 4,000 to 12,000

*Includes benefits of reduced fine particle concentrations associated with illustrative ozone controls applied to meet a primary ozone standard in the proposed range

22

Counties With Monitors Violating the March 2008 Ground-Level Ozone Standards 0.075 parts per million (Based on 2006 – 2008 Air Quality Data)

> 0.075 ppm

322 of 6751 monitored counties violate the standard

> 0.075 ppm

Notes: 1. Counties with at least one monitor with complete data for 2006 – 20082. To determine compliance with the March 2008 ozone standards, the 3-year average is truncated to three decimal

places.

23> 0.060 ppm > 0.065 ppm > 0.070 ppm

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.

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 650Notes:

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

> 7 ppm-hours > 15 ppm-hours

> 7 ppm-hours > 15 ppm-hours196 counties violate 15 ppm-hours

383 additional counties violate 7 ppm-hours for a total of 579

> 7 ppm-hours > 15 ppm-hours

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

Notes: 1. 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.

2. Controls applied are illustrative. States may choose to apply different control strategies for implementation. 3. EPA did not model future violations outside the continental U.S.4. EPA is proposing to determine compliance with a revised primary ozone standard by rounding the 3-year average to three decimal places.

> 0.060 ppm > 0.065 ppm > 0.070 ppm

Counties With Monitors Projected to Violate the Proposed Primary 8-hour Ground-Level Ozone Standards in 2020

0.060 - 0.070 parts per million

26

> 7 ppm-hours > 15 ppm-hours

> 7 ppm-hours > 15 ppm-hours

> 7 ppm-hours > 15 ppm-hours27 counties violate 15 ppm-hours

167 additional counties violate 7 ppm-hours for a total of 194

Counties With Monitors Projected to Violate the Proposed Secondary SeasonalGround-level Ozone Standards in 2020

7 – 15 parts per million - hours

Notes: 1. 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.

2. Controls applied are illustrative. States may choose to apply different control strategies for implementation. 3. 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 causal for short- and long-term exposures and

cardiovascular effects and mortality; likely causal for 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 suggestive for 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