### UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

The Honorable Jeremiah W. Nixon Governor ofMissouri P.O. Box 720 Jefferson City, Missouri 65102

Dear GovernorNixon: REGION 7 11201 RENNER BOULEVARD LENEXA, KS 66219



## AUG 1

## 92014

OFFICE OF THE REGIONAL ADMINISTRATOR

Thank you for your recommendation dated December 10, 2013, ofair quality designations for the 2012 revised primary annual fine particle National Ambient Air Quality Standard throughout Missouri. I appreciate the infonnation Missouri shared with the U.S. Enviromnental Protection Agency as we move forward to improve PM2.s air quality. This letter is to notify you ofthe EPA'spreliminaryresponse to Missouri's recommendation and to inform you ofour approach for completing the initial area designations for the 2012 revised p1imary annual PM2.s standard.

On December 14, 2012, the EPApromulgated a revised primary annual PM2.s NAAQS (78 FR 3086, January 15, 2013). In that action, the EPA revised the primary annual PM2.s standard, strengthening it from 15.0 micrograms per cubicmeter (Jlg/m3) to 12.0 Jlglm3; retained the existing 24-hourPM2.s standard at 35 Jlglm3; retained the existing 24-hourPM10 (coarse particle) standard at 150 Jlg/m3; and retained the current suite ofsecondaryPM standards. The EPA revised the primary annual PM2.s standardbased on an integrated assessment ofan extensivebodyofnew scientific evidence, which substantially strengthens ourbody ofknowledge regarding PM2.s-related health effects. Therevised primary annual PM2.s standard will provide increased protectionfor children, older adults, persons with pre-existingheart and lung disease, and other at-risk populations against an array ofPM2.s-related adverse health effects, includingprematuremortality, increased hospital admissions and emergency department visits, and development and exacerbation ofchronicrespiratory disease.

History shows us thatbetterhealth and cleaner air go hand-in-hand with economic growth. Working closely with the states and tribes, the 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, the 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 toreduce PM2.s airpollution. Within one year of promulgating a new orrevised air quality standard, the Clean Air Act requires the Governor ofeach
state to submit to the 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 to submittheir designation recommendations, including appropriate areaboundaries, byDecember 13, 2013.

As required bythe Clean Air Act, the EPA then promulgates designations for all areas across the country. The 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 forprevious PM2.s standards, the EPA intends to use a designation category of"unclassifiable/attainment" for areas that are monitoring attainment or do not have monitors, but for which the EPA has reason to believe are likely attainment and are not contributing to nearby violations. Additionally, the EPA intends to designate as "unclassifiable" those areas where the EPA cmmot detenninebased on available infom1ation whether the area is meeting the NAAQS or where EPAbas not detennined that the area contributes to anearbyviolation. At this time, the EPA is proceeding with intended initial area designations using quality-assured, ce1iified air quality monitoring data from 2011 to 2013.

Wehave considered the annual PM2.s designation recommendation submitted byMissomi on December 10, 2013, and have reviewed the relevant technical infonnation, including 2011-2013 air quality data. These data do not indicate any violation ofthe 2012 annual PM2.s NAAQS in Missouri. However, a recent EPA-conducted teclmical systems audit ofIllinois' monitoring program revealed data completeness issues for the State ofIllinois which affects Missouri areas/counties. Because ofthese data completeness issues, the EPA cannot determine whether the counties with the incomplete monitoring data are meeting or not meeting the NAAQS or whether counties nearby to those counties with incomplete monitoring data contribute to a nearby violation. Accordingly, the EPA intends to modify Missouri's recommended area designation and designate St. Louis area counties including Franklin, Jefferson, St. Louis, St. Louis City and St. Charles counties as unclassifiable. The EPA intends to designate the remainder ofMissouri as unclassifiable/attaimnent. A Technical Support Document, which provides additional detail regarding the status ofdata for Missouri and the rationale to support the EPA'sunclassifiable designation, is available onthe EPA's website at http://www.epa.gov/pmdesignations/2012standards/state.htm. IfMissouri has additional infonnation for the EPA to consider, please submit it to us by October 29,2014.

The 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 infonnation we receive, the EPAplans to promulgate final annual PM2.s designations in December of2014.

The EPA is committed to working with the states and tribes to share the responsibility ofreducing PM2.s airpollution. Current and upcoming federal standards and safeguards- includingpollution reduction rules for powerplants, vehicles, and fuels- will ensure steadyprogress to reduce PM2s-fonning pollution and will protectpublichealth in communities across the country. We look forward to a continued dialogue with you and your staffas we work togetherto implement the 2012 ammal PM2.s standard. Should you have any questions, please do not hesitate to contact me, orhave your staffcontact BeckyWeber ofmy staffat 913-551-7487 orweber.rebecca@epa.gov.
Sincerely,

# ~~l Karl Brooks

cc: Sara Parker Pauley, Director, Missouri Department ofNatural Resources