U N ITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D.C. 20460

The H onorab le Jerry Brown Governor of Califorina S tate Capito l, Su ite 1173 Sac rame nto, California 9581 4 Dear Governor Brown: 

## . DEC l 8 2014

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 C lean Air Act, the EPA has determined which areas are meeting the national ambient air quality standards for fine particle pollution and which areas must take steps to reduce emissions that contribute to v iolations of the standard. On December 14,2012 , the EPA strengthened the annual, health-based fine particle standard from 15.0 microgram s per cubic meter ( Jlg/m3) to 12.0 Jlg/m3

. Thousands of sc ientific studies have linked exposure to these tiny partic les-approximately 1/ 30th the size of a hum an hair

- with serious human health problems including premature death in people w ith heart and lun g di sease , nonfatal heart attacks , and increased ho s pital adm issions and doctor and emergency room vis its for respiratory and cardiovascular disease. I appreciate the in formation you and your s taf f have shar ed with the EPA throughout this process to assess fin e partic le pollution levels in communities across your state and the imp act of emission sources that could be contri butin g to unhealthy air. Af ter considering your recommendation s, reviewing the mo st recen t cer ti fied fine particle air quality data for your state and evaluating facto r s to assess contribution to n ea rby level s of fin e particle pollution, 

### I have determined that mo s t areas in your state meet the 2012 annual fine particle s tandard. As a resu lt, the EPA i s designatin g the majority of the state "unclas si fiab le/a ttai nrnent." Also consistent with your recommendations, I have determined that some areas in your state either do not meet the 2012 annual fine particle standard or they contribute to a nearby vio lation of the standard. The EPA i s designating those areas " nonattainrnent. " Nonattairunent areas will be required to take action to reduce fine particle pollution and meet the standard no later than 202 1
. As requi red by the Clean Air Act, those actions may include stricter controls on industrial facilities and add itional planning requiremen ts for transportation-related sources. The enclosed tab le li s ts the areas , and counties within them, that the EPA is designating nonattainrnent.

Internet Address (URL) • hllp : //www.epa.gov Recycled/Recyclable • Printed with Vegetable O i l Based I nks on 100% Poslconsumer, Procoss Chlorine Free Recycled PaperBecause air quality monitoring fo r 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 2 0 12 - 2014. If you would like the E PA to re-evalua te any areas within your state, please submit to the EPA, complete, quality

- assured and certified air quality data for 2014 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 th e 1997 and 2006 fine part icl e pollution standards are already work i ng to reduce unhealthy levels of fine particle pollution. In addition, current and upcoming federal standards and safeguards, including pollution reduction rules for power plants, veh icl es and fuels will assure steady reductions of fine particle pollution and will protect public health in communities across the country . Together, we have made considerable progress to reduce fine particle pollution. Nationwide, monitored

levels of fine particle pollution have fallen 34 percent s inc e 2000 when we first began nationwide monitoring for part icle s of this size. I am confident this progress will continue as we work together towards our shared goal of clean air . For additional information about these designations , please visit our website at: www.e p a . Q:ov/ p mdes i gnat i ons .

If you have ques t ions or co n ce rn s, please contact me or your staff may contact Mark Rupp, Deputy Associate Administrator for Intergovernmental Relations, at ru pp. marl-Ji«e p a . gov or at (202) 564-7178 . Enclosure

### Enclosure - Initial Nonattainment Area Designations for the 2012 Annual Fine Particle Standard, California

State Area Name 2014 EPA Designated Nonattainment Counties Imperial County, CA Imperial, CA (p) Fresno, CA Kern, CA (p) Kings, CA San Joaquin Valley Air Basin, CA Madera, CA Merced, CA CA San J oaquin, CA Stanislaus, CA Tulare, CA Los Angeles, CA (p) Los Angeles-South Coast Air Basin, Orange, CA CA Riverside, CA (p) San Bernardino, CA (p) P lumas County, CA Plumas, CA (p) (p) partial county