THE ADMINISTRATOR OF THE ENVIRONMENTAL PROTECTION AGENCY 

Mr. Joshua Stebbins 

Managing Attorney 

The Sierra Club 

50 F Street, NW, Eighth Floor 

Washington, D.C. 20001 

Dear Mr. Stebbins: 

WASHINGTON. D.C. 20460 

AUG 1 4 2014 

On behalf of the Sierra Club, you and your colleague Seth Johnson, filed on November 14, 2013, a 

petition requesting that the U.S. Envirorunental Protection Agency redesignate as nonattairunent 57 

areas with 2012 design values violating the 2008 National Ambient Air Quality Standards for ozone. 

Furthennore, the Sierra Club requested that the EPA set specific boundaries for the areas as identified in 

the petition. 

The EPA has carefully evaluated the issues and infonnation in your petition as well as infonnation 

obtained from the respective states with areas listed in your petition. For the reasons explained in the 

enclosure, the EPA is denying the petition using the discretion that the Clean Air Act affords me as 

Administrator to not initiate the redesignation process for any of the areas identified in the Sierra Club 

petition. 

As an initial matter, 22 areas identified in the petition are again attaining the ozone NAAQS based on 

2013 design values. As to the remaining areas, the EPA believes it is appropriate to allow time for 

affected states to consider appropriate measures to address the air-quality problems. The EPA expects 

that reductions in emissions of oxides of nitrogen and volatile organic compounds due to existing federal 

measures, such as the Tier 3 motor-vehicle standards, and state-led efforts will assist these areas in 

attaining the 2008 ozone NAAQS. The EPA plans to publish a notice of this denial in the Federal 

Register. 

I appreciate the Sierra Club and Earthjustice's interest in reducing ground-level ozone levels and in 

providing cleaner, healthier air for all Americans. 

Sincerely, 

Enclosure 

Thos pnpcr is prin ted woth vcgctable·oil·based inks and is 1 00-porcent poslconsumer recycled material, chlorone-free-processecl and recyclable. 
Enclosure 

Response to Petition from Sierra Club to Redesignate as Nonattainment 57 Areas with 2012 

Design Values Violating the 2008 8-Hom· National Ambient Air Quality Standards for Ozone 

By Petition dated November 14,2013, Sierra Club requested that the U.S. Environmental Protection 

Agency redesignate as nonattainment 57 areas with 2012 design values violating the 2008 national 

ambient air quality standards (NAAQS) for ozone. Sierra Club further requested that the EPA set 

specific boundaries for the areas, as identified in the Petition. For the reasons discussed below, the EPA 

is denying the Petition. 

Whenever the EPA promulgates a new or revised NAAQS, the EPA has a mandatory duty under CAA 

section 107(d)(l) to designate all areas in the country no later than 2 years from promulgation of the new 

or revised NAAQS. (The EPA may extend the deadline by up to I year if the EPA has insufficient 

information to complete the designations in 2 years.) For the 2008 ozone NAAQS, the EPA completed 

these initial area designations in spring of 2012. The EPA based the designations on the most recent 

cetiified air quality data available at that time (e.g., generally, 2008-2010 data and, in some cases, 2009-

2011 data). For areas designated as attainment that subsequently violate the NAAQS, the CAA provides 

the EPA with discretion regarding whether and when to redesignate such areas to nonattainment. Section 

107(d)(3) of the CAA states, "on the basis of air quality data, planning and control considerations, or 

any other air quality-related considerations the Administrator deems appropriate, the Administrator may 

at any time notify the Governor of any State that available information indicates that the designation of 

any area or pottion of an area within the State or interstate area should be revised." Thus, unlike initial 

designations, the Administrator does not have a mandatory duty to initiate the redesignation process. 

Ground-level ozone is not emitted directly into the air, but is created by chemical reactions between 

ozone precursors, primarily oxides of nitrogen (NOx) and volatile organic compounds (VOC), in the 

presence of sunlight. Therefore, the CAA and the EPA's regulations to control ozone focus on reducing 

emissions ofNOx and VOC. Emissions from industrial facilities and electric utilities, motor vehicle 

exhaust, gasoline vapors, and chemical solvents are some of the major sources ofNOx and VOC. 

Ozone design values are statistics that describe the air quality status of a given area relative to the level 

of a NAAQS. They are based on a 3-year average of the annual4111 highest daily maximum 8-hour ozone 

concentration. Variations in weather conditions play an important role in determining ozone levels and 

thus design values can fluctuate f!·om year to year. Ozone levels tend to be highest during the summer 

months, especially during periods of hot, dry and stagnant weather conditions. The EPA notes that the 

summer of2012 was characterized by unusually hot, dry, and stagnant weather conditions, while, 

conversely, the summer of2009 was characterized by cooler and wetter than normal conditions 

throughout much of the United States. These weather conditions contributed to annual4111 highest daily 

maximum 8-hour ozone concentrations which were 6 parts per billion (ppb) higher on average in 2012 

than in 2009. This translates to an average 2 ppb increase in ozone design values from the 2009-2011 

period to the 20 I 0-2012 period. 

In evaluating whether the agency should exercise its discretion under CAA section 107(d)(3) to initiate 

the redesignation process for the areas identified in the Petition, the EPA considered air quality trends 

and expected emissions reductions in the near term. The EPA tracks the levels of ozone and the other 

NAAQS pollutants in the air and how much of each pollutant (or the pollutants that form them) is 
emitted from various pollution sources. The agency reviews these values year after year to see how the 

levels and emissions of the pollutants have changed over time. Nationally, ozone levels have shown a 

notable decline since 2002. (See http://www.epa.govlairtrendslozone.html.) The EPA expects this 

overall long-term trend to continue as additional emissions reductions are achieved through existing 

regulations. Based on the 2013 ozone design values, 22 of the 57 areas identified in the Petition are 

again attaining the NAAQS. The EPA notes that if the EPA were to grant the Petition to initiate the 

redesignation process for one or more areas, we would base the redesignations on the most recent, 

quality assured air quality design values rather than the 2012 design values. Therefore, the EPA would 

not grant the Petition for any area for which the most current design value shows attainment. 

Our expectation that ozone levels will continue to decline is supported by emissions inventories and 

projected inventories ofNOx and VOC emissions that indicate significant emissions reductions in the 

coming years. The EPA compiles the National Emissions Inventory (NEI) 1 every 3 years. The NEI is a 

compilation of emissions data collected from state, local and tribal air agencies as well as from the 

EPA's emissions collection for emissions trading programs and from EPA emissions estimation tools 

and models. The 20 ll NEI is the most recent emissions inventory. In addition, the EPA has projected 

emissions for 2018,2 which have been compiled from a variety of sources and include projected 

emissions reductions from numerous existing EPA regulations. The 2018 projected emissions are 

estimated using the EPA models for electric generating utilities, on-road vehicles and nonroad engines, 

as well as by projecting 20 ll emissions to 2018 for other sources. A comparison of the 20 ll NEI and 

the projected 2018 emissions inventory provides a prediction of the change in NOx and VOC emissions 

over that several year period. 3 

Emissions ofNOx in the United States are expected to decline by 29 percent from 2011 through 2018, 

even when accounting for increases in some sectors, such as the oil and gas production industry. A 

comparison of the 2011 NEI and the projected 2018 emission inventory predicts a reduction ofNOx 

emissions from 14.1 million tons in 20 II to I 0 million tons in 2018, a 4.1 million ton reduction. 

Existing EPA regulations primarily account for those reductions, which come from a variety of sources. 

On-road mobile source emissions reductions of 3 million tons are predicted from Tier 2, heavy duty, and 

other motor vehicle standards implemented years ago, as older vehicles are replaced with newer cars and 

trucks meeting better fuel economy and other standards. The 3 million ton estimate also includes early 

reductions from the recently finalized Tier 3 standards that EPA expects will provide significant NOx 

emissions reduction benefits from on-road mobile sources in 2018. Approximately 740,000 tons ofNOx 

reductions come from locomotive and nonroad engine rules. Reductions from electric generation 

account for about 500,000 tons of the projected reductions, resulting from the ongoing EPA NOx trading 

programs as well as other factors such as increased use of natural gas. Expected NOx emissions 

increases of about 140,000 tons for the oil and gas sector and about 30,000 tons for other smaller sectors 

partly offset the reductions, but the net result is still an overall 29 percent decrease in NOx emissions. 

Emissions ofVOC in the United States are expected to decline by 10 percent from 2011 through 2018, 

even when accounting for increases in some sectors such as the oil and gas production industry. A 

comparison of the 20 II and 2018 emission inventories predicts a reduction of VOC from 17.2 million 

1 20 II National Emissions Inventory Technical Support Document 

(http:! /www. epa. govlttn/ chieflnet/20 II invent01y. html#inven/Otydoc ). 2 20 II and 2018 Emissions Modeling Platform Technical Support Document 

(http:! /www. epa.gov/1/n/ chief! emch/index. htm/#20 I !). 3 The projected 2018 emissions inventory may be used by the Office of Air and Radiation in several contexts, including the 

development of rules related to the transport of air pollution and the NAAQS. 

2 
tons in 201 I to 15.5 million tons in 2018, a 1.7 million ton reduction. Existing EPA regulations 

primarily account for those reductions, which come from a variety of sources. On-road mobile source 

reductions of I .2 million tons come from Tier 2, heavy duty, and other standards implemented years 

ago, as older vehicles are replaced with newer cars and trucks meeting better fuel economy and other 

standards. The I .2 million ton estimate also includes early reductions from the recently finalized Tier 3 

standards that the EPA expects will provide VOC emission reduction benefits from on-road mobile 

sources in 2018. Another approximately 664,000 tons ofVOC reductions come from nonroad engine 

rules. Expected VOC increases of about 298,000 tons for the oil and gas sector and about 27,000 tons 

for other smaller sectors partly offset the reductions, but the net result is an overall I 0 percent decrease 

in VOC. 

The EPA notes that, based on 2013 design values, all but I of the areas identified in the Petition would 

be classified as Marginal if redesignated to nonattainment. The Marginal classification is for 

nonattainment areas with ozone levels closest to the level of the NAAQS. Under CAA section I 82(a), 

Marginal areas have nominal planning requirements (e.g., submission of periodic emissions inventory 

and establishment of reasonably available control technology) and are not required to submit attainment 

demonstrations. Attainment demonstrations, which are required for nonattainment areas with higher 

classifications, are state plans that describe the local, regional and national control measures to be 

implemented to reduce emissions in order for the area to demonstrate attainment by the required 

attainment date. When Congress amended the CAA in I 990, it anticipated that nonattainment areas with 

ozone concentrations close to the level of the NAAQS would likely come into attainment within 3 years 

after designation as nonattainment without any additional local planning. Therefore, redesignating the 

areas identified in the Petition to nonattainment that would be classified as Marginal would not on its 

own result in additional local attainment planning requirements for the areas. The EPA believes that the 

NOx and VOC emissions reductions discussed above that are projected in the near term from existing 

regulations will assist the areas identified in the Petition in meeting the ozone NAAQS. 

For newly violating areas, the EPA and states may pursue various options for addressing emerging air 

quality problems. Historically, EPA's recommended approach has been to assist state and local officials, 

local stakeholders and tribes to develop collaborative strategies to bring newly-violating areas back into 

attainment as soon as possible. The EPA Regional Offices address the emerging air quality problems as 

part of the annual grant negotiations with their states. The annual EPA grant guidance includes a 

performance measure to have the EPA Regional Office and the respective state target grant funds to 

specific actions to bring newly violating designated attainment areas into compliance with the respective 

NAAQS. (See Performance Measure OAQPS NJO in OAR National Program Guidance Fiscal Year 

2014 - http:l/www2.epa.gov/planandbudget/national-program-manager-guidances#fY2014.) The grant 

agreements have included enforceable and voluntary agreements, such as the EPA's Ozone Advance 

Program,4 to reduce emissions. Nineteen of the 57 areas listed in the Sierra Club Petition have chosen to 

participate in Ozone Advance, a voluntary program that encourages emissions reductions in ozone 

attainment areas by providing EPA assistance to help these areas continue to meet the ozone NAAQS. 

While the program itself does not establish any regulatory requirements, it provides a framework for 

local action and for closer collaboration with the EPA. The EPA provides technical advice and other 

support including identifying available tools and resources that may be used to put plans in place to keep 

ozone levels under control. 

For the reasons explained above, the EPA is choosing not to exercise its discretion to initiate the 

redesignation process for the areas identified in the Sierra Club Petition. Furthermore, because the EPA 

4 See Ozone Advance Program website at http://www.epa.gov/ozonepmadvance/. 

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is denying the Petition and is not initiating the process to redesignate any of the 57 areas identified in the 

Petition, the issue of appropriate nonattainment area boundaries is not triggered. However, the EPA 

notes that, even if the EPA were to grant the Petition to initiate the redesignation process for one or more 

areas, we would not grant the request to establish specific boundaries for designated nonattainment 

areas. Section I 07 ( d)(3 )(A -C) of the CAA establishes the process for redesignating areas to 

nonattainment, which is an interactive process between states and the EPA. It is only upon completion of 

that process resulting in a redesignation of an area to nonattainment that the final boundaries of the 

nonattainment area would be established. 

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