### State ofUtah GARY R. HERBERT Governor SPENCER J. COX Lieutenant Governor 

## Office ofthe Governor

Shaun McGrath, Regional Administrator U.S. Environmental Protection Agency, Region 8 1595 Wynkoop Street Denver, Colorado 80202-1129 Dear Mr. McGrath: December 10,2013 

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Re: Utah Area Designation Recommendations for the 2012 PM2.s NAAQS CIO c

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The purpose ofthis letter is to recommend appropriate PM2 .5 area designations for all areas ofthe State ofUtah. These recommendations are made in response to EPA's December 14, 2012, revision to the National Ambient Air Quality Standard (NAAQS) for PM25· Section 1

07 (d) ofthe Clean Air Act (the Act) directs states to provide their recommendations to EPA following promulgation ofnew or revised NAAQS. EPA's 2012 NAAQS revision lowered the annual PM2 .5 standard from15 flg/m3 to12 flg/m3, and retained the 24-hour standard at 35 flg/m3. Utah has monitored PM2s since 2000 and has never identified any area within the state that violated the annual standard, even at 12 flg/m3. Data collected by Utah's PM2.s monitoring network shows all areas comply with this new standard 1• Hence, I am not recommending at this time any new areas within the state that should be designated as "Nonattainment" for PM2.S· There are presently three distinct areas in Utah that have been designated nonattainment for PM2 .5. The following areas are identified and described in 40 CFR 81.345: the Logan, UtahIdaho, PM2 .5nonattainment area; the Provo, Utah, PM25 nonattainment area; and the Salt Lake City, Utah, PM2 .5 nonattainment area. Each was designated nonattainment for the 2006 24-hour NAAQS. The boundary for each ofthese areas was defined, in consultation with EPA, based on a rigorous analysis ofnine factors. EPA's latest guidance on PM25area designations2identifies

1 EPA has directed States to make their area designation recommendations based on ambient air data collected for calendar years 2010- 2012. This data has been quality assured and sent to EPA, and is available in EPA's AQS data system. 2 "Initial Area Designations for the 2012 Revised Primary Annual Fine Particulate National Ambient Air Quality Standard", April16, 2013.

Utah State Capitol, Suite 200 •P.O. Box 142220 •Salt Lake City, Utah 84114-2220 •Telephone (801) 538-1000 

# '""' ....- c::> c---1**~** .,-l u •..LJ 0five factors to be considered in defining nonattainment area boundaries and notes that they are comparable to the factors that states have successfully used in making area designations for the 1997 and 2006 PM2.5 NAAQS. These include air quality data, emissions and emissions related data, meteorology, geography 

### I topography, andjurisdictional boundaries. My recommendation is that each ofthese existing nonattainment areas should specifically be designated as "Attainment 

### I Unclassifiable" with respect to the 2012 annual NAAQS for 

### PM2.s· All other areas ofthe state not identified as areas ofnonattainment should also be designated as "AttainmentiUnclassifiable." The one exception to this recommendation concerns all Tribal Lands, over which Utah Division ofAir Quality has no jurisdiction in such matters. It will be left to the EPA and the Tribes to designate these areas as they see fit. The submittal ofany further documentation, which EPA determines is necessary to verify or otherwise meet the requirements of section 107 (d) ofthe Act, will be submitted by Bryce Bird, Director ofthe Division ofAir Quality, and any questions your agency may have concerning this submittal should be addressed to Mr. Bird at (801)536-4064. Sincerely,

# ~(4**tJ....~-{-** Gary R. Herbert Governor