UNITED STATES EN V IRONMENTAL PROTECTION AGEN CY WASHINGTON, D.C. 20460

The Honorable Steve Bullock Governor of Montana P.O. Box 200801 Helena, Montana 59620-080 I Dear Governor Bullo ck: THE ADMINISTRATOR

I am writing to summarize the U.S. Environmental Protection Agency's recent action to address fine particle pollution in your state. As required by the Clean Air Act, the EPA has determined which areas are meeting the national ambient air quali ty standards for fine particle pollution and which areas mu st take steps to reduce emissions that contribute to violatio n s of the standard. On December 14, 20 12, the EPA strengthened the annua l, health-based fine particle standard from 15.0 micrograms per cubic meter (!lg/m3 ) to 12.0 11g/m3

. Thousands of scien tific studies have link ed exposure to these tiny particles-approximately l/30 th the s ize of a h uman hair-with serious human heal th problems includin g premature death in people with heart and lung disease , nonfatal heart attacks , and increased hospital admissions and doctor and emergency room visits for respiratory and cardiovascular disease. I appreciate the informat ion you and your staff have shared with the EPA throughout this process to assess fine particle pollution levels in communities across your state and the impact of emission sources that could be co n tributing to unhealthy air. After considering your recommendations , reviewing the most recent certified fine parti cle air quality data for your state and evaluatin g facto rs to assess co ntribu tion to nearby levels of fine particle pollution , I hav e determin ed that no area w ith in Montana vio l ates the 2012 standard or contributes to a nearby viola tion of the standard. As a re s ult , the E PA i s designating all of Montana " unclassifiable/ attainment." Because air quality monitoring for 2014 is nearly complete , if a state or tribe requests it, the EPA will evaluate the status of an a rea based on its annual fine particle monitoring data for 2012

- 2014. If you would like the EPA to re-evaluate any areas within you r state, please submit to the EPA, complete, qualit y-assure d and cert i fied air quality data for 2014 by February 27,2015. The EPA shares respo n sib ili ty wit h th e states and tribes for managin g particl e pollution levels. Efforts by states and tribes to attain the 1997 an d 2006 fine p a rticle po llution standards are a lready working to reduce unhealthy levels of fine particle pollution. In addition, current and upcoming federal standards and safeguards, including pollution reduction rules for power plants, vehicles and fuels will assure stead y reductions of fine particle pollution and will protect public health in communit ies ac ross the country.

lntemel Address (URL) • http ://www
. epa . gov Recycled/Recyclable • Printed w i th Vegetable Oil Based I nks on 100% Postconsumer
. Process Ch l ori ne Free Recycled PaperTogether , we have made cons i derable progress to reduce fine particle pollution. Nationwide, monitored levels of fine particle pollution fell 34 percent since 2000 whe n we first began nationwid e monitoring for particles of this size. I am confident this progress will acce l erate as togethe r we continue to work towards our shared goal of clean air. For additional information about these designations, p l ease visit our website at: www.epa.gov / pmdesignations .

If you have questions or concerns, please contact me or your staff may contact Mark Rupp , Depu ty Associate Adm inistrator for Intergovernmental Re l ations, at rupp.mark@epa . gov or at (202) 564-7178.