UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASH I NGTON , D.C. 2046 0

The Honorab le Scott Walker Governor of Wiscons in 115 East Capitol Madison , Wisconsin 53702 Dear Governor Walker: 

# DEC1 

## 8 20H

T H E ADMIN I STRATOR

1 am writing to summarize the U.S. Environmental Protection Agency's recent action to address fine particle pollution in yo4r state. As required by the C lean Air Act , the EPA has determined which areas are meeting the national ambi ent air quality standards for fine pa rticle pollution and which areas must take steps to reduce emissions that contribute to violations of the s tandard. On D ecember 14, 20 12, the EPA st rengthened the annual , health-based fine particle standard from 15.0 micrograms per cubic meter (11g/m3 ) to 12.0 11g/m3

. Thousand s of sc ientific studies have linked exposure to these tiny particles

- approximately 1/ 30th the size of a human hair

- with seri ous human health problems including premature death in people with heart and lung disease , nonfatal heart attacks, and increased ho s pital admissions and doctor and emergency room visits for respiratory and cardiovascular disease. I appreciate the information you and your staff have shared with the EPA throughout this process to assess fine particle po llution levels in communities across your state and the impact of emission so urces that could be contributing to unhealthy air. After considering your recommendations , reviewing the most recent certified fine particle air quality data for your state and evaluating factors to assess contribution to nearby levels of fine particle pollu tion, I have determi ned that no a r ea wi thin Wiscons in vio l ates the 2012 standard or co ntribute s to a nea rby vio lation of the standard. As a result, the EPA is designating all of Wiscon s in " 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 area based on its annual fine particle monitoring data for 2012

- 20 14. If you wo u ld li ke the EPA to re-evaluate any areas within your state, please sub mit to the EPA, comp lete , quality-assured and certified air quality data for 20 14 by February 27,2015. The EPA shares responsibility with the states and tribes for managing particle pollution levels. Efforts by states and tribes to attain the 1997 and 2006 fine particle pollution standards are already working to reduce unh ealthy level s of fine particle pollution. In addition, current and upcoming federal standards and safeguards, including pollution reduction ru les fo r power plants , vehi cles and fue l s will assure steady reductions of fi ne particle po ll ution and will protect pub lic health in communities across the country.

l n teme t Ad dress (URL ) • h ttp :// ww w . epa . go v Recycted/Recyctabte • Printe d w i th V eg et a b l e Oil Based I nk s o n 100% Postconsume r , P r ocess C hl o rine Free Recycl ed PaperTogether, we have made conside r able p r ogress to reduce fine part i cle pollution. Nationwide, mo n itored levels · of fine particle pollu t ion fell 34 percent since 2000 whe n we first began n at i o n wide monitoring for particles of this size . I am confident this progress will accelerate as together we continue to work towa r ds ou r shared goa l of clean a i r. Fo r add i t i onal information abou t these designations, please visit

our webs i te at: www.epa.go v / pmdesignations . I f you have ques t ions or concerns, please contact me or your staff may contact Mark Rupp, Deputy Associate Adm i nistrator for I ntergovernmental Re l at i ons, at rupp . mark @e pa.gov or at (202) 564 - 7178. cerely, r1Aii)