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



### The Honorable Martin J. O'Malley Governor ofMaryland State House, 1 00 State Circle Annapolis, Maryland 21401-1925
Dear Governor O'Malley: 

### AUG 1- 

### 9Z014

Thank you for your recommendations, dated January 16,2013 [sic], received by EPA on January 23, 2014, regarding air quality designations for the 2012 revised primary annual fine particle (PM2.s) National Ambient Air Quality Standard (NAAQS) throughout Maryland. I appreciate the infmmation Maryland shared with the U.S. Environmental Protection Agency as we move forward to improve PM2.s air quality. This letter is to notify you ofEPA's preliminary response to Maryland'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.s NAAQS (78 FR 3086, January 15, 2013). Inthat action, EPA revised the primary annual PM2.s standard, strengthening it from 15.0 micrograms per cubic meter ()lg/m3) 

### to 12.0 

### )lglm3; 

### retained the existing 24-hour PM2.s standard at 35 

### )lglm3; 

### retained the existing 24-hour 

### PMw (coarse particle) standard at 150 )lg/m3; 

### and retained the current suite ofsecondary PM standards. EPA revised the primary annual 

### PM2

.sstandard based on an integrated assessment ofan extensive body of new scientific evidence, which substantially strengthens our body ofknowledge regarding PM2.srelated health effects. The revised primary annual PM2.s standard will provide increased protection for children, older adults, persons with pre-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 better health and cleaner air go hand-in-hand with economic growth. Working closely with the 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 withthe states and tribes to identify areas in the country that meetthe standards and those that need to take steps to reduce PM2

.s air pollution. Within one year ofpromulgating a new or revised air quality standard, the Clean Air Act (CAA) requires the Governor ofeach state to submitto EPA a list ofall areas in the state, with a designation recommendation for each area. As a first step in implementing the 2012 annual PM2.s standard, Governors were required to submit their designation recommendations, including appropriate area boundaries, by December 13, 2013.

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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 or ifit 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 reason to 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 whetherthe area is meeting the NAAQS or where EPA has not determined that the area contributes to a nearby violation. Atthis time, EPA is proceeding with intended initial area designations using quality-assured, certified air quality monitoring data from 20 11 to 2013. ·
We have considered the annual PM2.s designation recommendations submitted by Maryland on January 16, 2013 [sic] and have reviewed the relevant technical information, including 201 1 -2013 air quality data. These data do not indicate any violation ofthe 2012 annual PM2

.sNAAQS in Maryland or contribution to any nearby area. Accordingly, EPA intends to designate the entire State ofMaryland 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-day public comment period shortly inthe Federal Register

. After considering the additional informationwe receive, EPA plans to promulgate final annual PM2.s designations in December of2014.
EPA is committed to working withthe 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 powerplants, 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 togetherto implement the 2012 annual PM2.s standard. Should you have any questions, please do not hesitate to contact me, or have your staffcontact Mrs. LindaMiller, EPA's Maryland Liaison, at (215) 814-2068 or miller.linda@epa.gov. Sincerely,

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cc: Honorable Robert M. Summers, Secretary Maryland Department ofthe Environment George Abum, Director Regional Administrator

Air & Radiation Management Administration, Maryland Department ofthe Environment