UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION Ill 1650 Arch Street Philadelphia, Pennsylvania 19103-2029



### The Honorable Vincent C. Gray Mayor ofDistrict ofColumbia John A. Wilson Building 1350 Pennsylvania Avenue, N.W. Suite 316 Washington, D.C. 20004
Dear Mayor Gray: 

### AUG 

## t 9Z014

Thank you for your recommendations regarding air quality designations for the 2012 revised primary annual fine particle (PM2.s) National Ambient Air Quality Standard (NAAQS) throughout the District ofColumbia. I appreciate the informationthe District ofColumbia shared with the U.S. Environmental Protection Agency (EPA) as we move forward to improve PM2.s air quality. This letter is to notify you ofEPA'spreliminaryresponse to the District of · Columbia's recommendations and to inform you ofour approach for completing the initial area designations for the 2012 revised primary annual PM2.s standard.
On December 14, 2012, EPA promulgated a revised primary annual PM2

.sNAAQS (78 FR 3086, January 15, 2013). Inthat action, EPArevised the primary annual PM2.s standard, strengthening it from 15.0 micrograms per cubic meter (J.Lg/m3) 

### to 12.0 J.Lg/m3; 

### retained the existing 24-hour PM2.s standard at 35 J.Lg/m3; 

### retained the existing 24-hour PM10 (coarse particle) standard at 150 J.Lg/m3; 

### and retained the current suite ofsecondary PM standards. EPA revised the primary annual PM2.s standard based on an integrated assessment ofan extensive body of new scientific evidence, which substantially strengthens ourbody ofknowledge regarding PM2.srelated health effects. The revised primary annual PM2.s standard will provide increased protection for children, older adults, persons withpre-existing heart and lung disease, and other at-risk populations against an array ofPM2.s-related adverse health effects, including premature mortality, increased hospital admissions and emergency department visits, and development and exacerbation ofchronic respiratory disease. History shows us that betterhealth and cleaner air go hand-in-hand with economic growth. Working closely withthe states and tribes, EPA is implementing the standards using a commonsense approach that improves air quality and minimizes the burden on state, local, and tribal governments. As part ofthis routine process, EPA is working with the states and tribes to identify areas inthe country that meetthe standards and those that need to take steps to reduce PM2.s air pollution. Within one year ofpromulgating a new orrevised air quality standard, the Clean Air Act (CAA) requires the Mayor ofthe District ofColumbia and the Governor ofeach state to submit to EPA a list with a designation recommendation for each area. As a first step in implementing the 2012 annual PM2

.s standard, the Mayor ofthe District

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ofColumbia and the Governors were required to submit their designation recommendations, including appropriate area boundaries, by December 13, 2013.
As required by the CAA, EPA then promulgates designations for all areas across the country. EPA designates an area as "nonattainment" ifit is violating the 2012 annual PM2.s NAAQS orifit is contributing to a violation ofthe NAAQS in a nearby area. Consistent with designations for previous PM2.s standards, EPA intends to use a designation category of "unclassifiable/attainment" for areas that are monitoring attainment or do not have monitors, but for which EPA has reasonto believe are likely attainment and are not contributing to nearby violations. Additionally, EPA intends to designate as "unclassifiable" those areas where EPA cannot determine based on available information whether the area is meeting the NAAQS or where EPA has not determined thatthe area contributes to a nearby violation. At this time, EPA is proceeding with intended initial area designations using quality-assured, certified air quality monitoring data from 2011 to 2013.
We have considered the annual PM2

.s designation recommendations submitted bythe District ofColumbia and have reviewed the relevant technical information, including 2011-2013 air quality data. These data do not indicate any violation ofthe 2012 annual PM2.s NAAQS in the District ofColumbia or contribution to any nearby area. Accordingly, EPA intends to designate the entire District ofColumbia as unclassifiable/attainment.
EPA will make its preliminary designation decisions and supporting documentation available to the general public for review and comment. We will be announcing a 30-daypublic commentperiod shortly in the 

### Federal Register. After considering the additional information we receive, EPA plans to promulgate final annual PM2

.s designations in December of2014.
EPA is committedto working with the states and tribes to share the responsibility of reducing PM2.s air pollution. Current and upcoming federal standards and safeguards- including pollution reduction rules for power plants, vehicles, and fuels

- will ensure steady progress to reduce PM2.s-forming pollution and will protectpublic health in communities across the country. We look forward to a continued dialogue with you and your staffas we work together to implementthe 2012 annual PM2.s standard. Should you have any questions, please do not hesitate to contact me, orhave

_ your staffcontact Ms. Arnie Howell, EPA's District ofColumbia Liaison, at (215) 814-5722 or**howell.amie@epa.gov~**

cc: Honorable Keith A. Anderson, Director District Department ofthe Environment Cecily Beall, Associate Director Regional Administrator

Air Quality Division, District Department ofthe Environment