THE ADMINISTRATOR OF THE ENVIRONMENTAL PROTECTION AGENCY

The Honorable Gregory Mendoza Governor of Gila River Indian Community P.O. Box 97 Sacaton , Arizona 85147 Dear Governor Mendoza: WASHINGTON, D
. C
. 20460



### DEC 

## 1 8 2 \'J\4

I would like to summarize the U.S. Environmental Protection Agency ' s recent action to address fineparticle pollution on yo ur re servation. As required by the C lean Air Act, the EPA has determined whi ch areas are meeting the national amb ient-air-quality standards for fine-particle pollution and which areas mu st take steps to reduce emissions that contribute to violations of the standard. The EPA on December 14 , 2012, stre ngthened the annual , health-based fine-particle standard from 15.0 micrograms per cubic meter

**(~-tg/m )**  to 12.0

**~t g/m**  **.** Thousands of scientific studies have linked exposure to these tiny particles

- approximately 1/30th the s ize of a human hair- with serious health probl ems including premature death in peop le with heart and l ung disease, nonfatal heart attacks and increased ho s pital admissions and do c tor and emergency-room vi sits for respiratory and cardiovascular disease. I appreciate the information you and your staff have shared with the EPA throughout this process to as s e s s fine-particle -p ollution levels in communities across your reservation and the impact of emission sources that could be contributing to unhealthy air. After consider ing your recommendations, reviewing the most recent certified fine-particle air-quality data for your reservation and evaluating factors to assess contri bution to nearby levels of fine -p article pollution, I have determin ed that no area within the Gila River Indian Community reservation violates the 2012 standard or contributes to a nearby violation of the standard
. As a result , the EPA is designating all of the Gila River Indian Community reservation
" unclassifiable/attainment. " B eca use air-quality monitoring for 2014 is nearl y complete , the EPA , at a tribe· s request, will evaluate th e s tatu s of an area based on its annual fine-particle-monitoring data for 201 2-14. Ifyou would like the EPA to re-evaluate any are as within your reservation , please subm it complete, quality-assured and ce rti fied air-quality data for 2014 to the EPA by February 27 , 2015. I recognize that 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 reduc e unhealthy levels of fine-particle pollution. In addition , current and upcoming federal standards and safeguards , including pollution-reduction rule s for power plants , vehicles and fuels will ensure steady reductions of fine-particle pollution and will protect public health in communities across the nation.

This paper is printed with vegetable-oil-based inks and is 100-percent postconsumer recycled material, chlorine-free-processed and recyclableTogether we have made considerable progress in reducing fine-particle pollu t i on. Nationwide moni t ored l evels of [me-particle pollut i on have fallen 34 percent since 2000 when we firs t began such monitoring for particles of this size. I am confident this progress will continue as we work toward our shared goal of clean air.

For additional inf ormation about these designations , please visit www.epa.gov /p mde sig nations. Sincere l y,