UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

REGION Ill 

1650 Arch Street 

Philadelphia, Pennsylvania 19103-2029 

The Honorable Jack Markell 

Governor of Delaware 

Tatnall Building 

150 William Penn Street, 2nd Floor 

Dover, Delaware 19901 

Dear Governor Markell: 

AUG 19 Z014 

Thank you for your recommendations, dated November 21, 2013, regarding air quality 

designations for the 2012 revised primary annual fine particle (PM2.s) National Ambient Air 

Quality Standard (NAAQS) throughout Delaware. I appreciate the information Delaware 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 of EPA's preliminary response to Delaware's 

recommendations and to inform you of our 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). In that action, EPA revised the primary annual PM2.s standard, 

strengthening it from 15.0 micrograms per cubic meter (!-Lg/m3

) to 12.0 !-Lg/m3

; retained the 

existing 24-hour PM2.s standard at 35 1-Lg/m3

; retained the existing 24-hour PM10 (coarse particle) 

standard at 150 I-Lg/m3

; and retained the current suite of secondary PM standards. EPA revised 

the primary annual PM2.s standard based on an integrated assessment of an extensive body of 

new scientific evidence, which substantially strengthens our body of knowledge 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 of PM2.s-related adverse health effects, including premature 

mortality, increased hospital admissions and emergency department visits, and development and 

exacerbation of chronic 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 of this routine process, EPA is working with the states and tribes to 

identify areas in the country that meet the standards and those that need to take steps to reduce 

PM2.s air pollution. Within one year of promulgating a new or revised air quality standard, the 

Clean Air Act (CAA) requires the Governor of each state to submit to EPA a list of all 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" if it is violating the 2012 annual PM2.s 

NAAQS or if it is contributing to a violation of the 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 whether the area is meeting the NAAQS or 

where EPA has not determined that the 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 by 

Delaware on November 21, 2013 and have reviewed the relevant technical information, 

including 2011-2013 air quality data. These data do not indicate any violation of the 2012 

annual PM2.s NAAQS in Delaware or contribution to any nearby area. Accordingly, EPA 

intends to designate the entire State of Delaware 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 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 committed to 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 protect public health in communities across the country. 

We look forward to a continued dialogue with you and your staff as we work together to 

implement the 2012 annual PM2.s standard. Should you have any questions, please do not 

hesitate to contact me, or have your staff contact Ms. Arnie Howell, EPA's Delaware Liaison, at 

(215) 814-5722 or howell.amie@epa.gov. 

Since;;,_ If& A. Garvin 

Regional Administrator 

cc: Honorable David Small, Secretary 

Department ofNatural Resources and Environmental Control 

Ali Mirzakhalili, Director 

Division of Air Quality, Department ofNatural Resources and Environmental Control