UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION 8

Ref: 8P-AR

The Honorable Steve Bullock Governor ofMontana Montana State Capitol Building P.O. Box 200801 Helena, Montana 59620-080I

Dear Governor Bullock: 1595Wynkoop Street DENVER, CO 80202-1129 Phone 800-227-8917 http://www.epa.gov/region08



## AUG 1

## ~ 2014

Thank you for your recommendations dated December2, 2013 ofair quality designations for the 20 12 revised primary annual fine particle (PM2.s) National Ambient Air Quality Standard (NAAQS) throughout Montana. I appreciate the information Montana shared with the U.S. Environmental Protection Agency as we move forward to improve PM2.s air quality. This letter is to notify you ofthe EPA'spreliminary response to Montana'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, the EPA promulgated a revised primary annual PM2.sNAAQS (78 FR 3086, January 15, 2013). In that action, the EPA revised the primary annual PM2.s standard, strengthening it from 15.0 micrograms percubic meter (!-lg/m3) to 12.0 !-!g/m3; retained the existing 24-hourPM2.s standard at 35 !-lg/m3; retained the existing 24-hourPM10 (coarse particle) standard at 150 !-lg/m3; and retained the current suite ofsecondary PM standards. The EPA revised the primary annual PM2.s standard based on an**integrated.ass~ssment** ofan extensive body ofnew scientific evidence, which substantially strengthens ourbody ofknowledge regarding PM2.s-related 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 otherat-riskpopulations 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 with the states and tribes, the EPA is implementingthe 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 countrythat
meet the standards and those that needto take steps to reduce PM2.s airpollution. Within one year of promulgating a new orrevised air quality standard, the Clean AirAct (CAA) requires the governor of each 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 submit their designation recommendations, including appropriate area boundaries, by December 13, 2013.As required by the CAA, the EPAthenpromulgates designations for all areas across the country. The 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, the EPA intends to use a designation category of"unclassifiable/attainment" for areas that are monitoring attainment or do not have monitors, but for whichthe 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 cannot determine based on available information whether the area is meeting the NAAQS orwhere EPA has not determined thatthe area contributes to a nearby violation. Atthis time, the EPA is proceeding with intended initial area designations using quality-assured, certified air quality monitoring data from 2011 to 2013.

We have consideredthe annual PM2.s designationrecommendations submittedby Montanaon December 2, 2013, and have reviewed the relevanttechnical information, including 2011-2013 air quality data. These data do not indicate any violation ofthe 2012 annual PM2.s NAAQS in Montanaor contributionto any nearby area. Accordingly, the EPA intends to designate the entire state ofMontana

as unclassifiable/attainment.

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 comment period shortly in the FederalRegister. After consideringthe additional information we receive, the EPA plans to promulgate final annual PM2.s designations in December of2014.

The EPA is committed to working withthe states and tribes to share the responsibility ofreducing 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 withyou and your staffas we worktogetherto implementthe 2012 annual PM2.s standard. Shouldyouhave any questions, please do not hesitate to contact me, orhave your staffcontact Crystal Ostigaard ofmy staffat (303) 312-6602 or ostigaard.crystal@epa.gov.

cc: Tracy Stone-Manning, Director, DEQ Dave Klemp, Chief, ARMB Regional Administrator

Janet G. McCabe, Acting Assistant Administrator for Air and Radiation Stephen D. Page, Director, Office ofAir Quality Planning and Standards