MATIHEW H. MEAD STATE CAPITOL THE STATE OF WYOMING GOVERNOR CHEYENNE, WY 82002 

# Office ofthe Governor January 12,2011 Mr. James B. Martin, Regional Administrator US Environmental Protection Agency, Region 8 1595 Wynkoop Street Denver, CO 80202-1129 Dear Mr. Martin: In response to your letter regarding health-based National Ambient Air Quality Standards (NAAQS), the State ofWyoming is making recommendations on attainment or nonattainment classifications for the State of Wyoming for the I-hour primary standard for nitrogen dioxide (NOJ ) NAAQS that became effective on January 22, 2010. The State has used the most recent three years ofN02 monitoring data available to make attainment recommendations. The results and supporting data are found in Attachment 1 to this letter. The State used your letter dated November 9,2010 and 40 CFR 50 and Appendix S, the National Primary and Secondary Ambient Air Quality Standards for Oxides ofNitrogen (\vith nitrogen dioxide as the indicator) to determine appropriate boundaries for State designations. Based on this guidance, the State would like to designate the regions listed below as "attainment" for the current I-hour primary 'standard for nitrogen dioxide.

Converse County Crook County Fremont County Attainment Attainment Attainment Attainment Attainment Attainment
RECEIVED U.S. EPA Region 8 RA'sOfflce 

## JAN 1 4 2011 PHONE: (307) 777-7434 FAX: (307) 632-3909Mr. James B. Martin January 20,2011 Page 2


### Attainment Attainment Attainment Attainment Attainment Attainment Attainment Attainment Attainment Attainment Attainment Attainment Attainment Attainment Attainment Attainment The State went ahead and made "attainment" recommendations for all areas since the current monitoring network shows no violations and there are no requirements upon the State to deploy a new monitoring network to measure traffic impacts. There are portions ofthe above-mentioned counties which are under thejurisdiction of Tribal Authorities. It 

### is our understanding that Tribal designations will be made separately from State designations. We look forward to your timely review and approval ofthis request. Ifyou have any questions concerning the details ofthis recommendation, please feel free to contact the State of Wyoming's Air Quality Division Administrator, Mr. Steven A. Dietrich, at 307-777-7391. Best regards,
Governor cc: John V. Corra, DEQ Director Steven A. Dietrich, AQD Administrator Christine Anderson, AQD Cara Keslar, AQD Chad Schlichtemeier, AQD.... ....."tIOtlWQS AnnUIII PrImIIry o.ta CarnpIMeI_ MonIIiDr Name AQPSltaID Va, Y111ue(Ppbl 

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# ---'*'I 1IIuIIder8alln 5 6-005-0123 2007 1 . 8 88% 2008 1.73 71% 2009 1.68 83% South Campbell County 56-005 -0456 2007 4 . 13 80% 2008 3.07 85% 2009 2.63 89% SOUdtPIIS 56-013-0099 2007 0.6 63% 2008 0.48 72% 2009 0 .23 95% IIIouIcIIr 56-035-0099 2007 2.65 48% 2008 1.79 68% 2009 2.92 89% Daniel 56-035-0100 2007 0.27 99% I I 2008 0.12 98% 2009 0 .3 99%

- Wamsutter 56-037-0200 2007 6.61 90% 2008 5.28 93% 2009 5 . 19 85% IMurphy Ridge 56-041 -0lO1 2007 1.73 98% 2008 2.33 98% 2009 1 .85 95% Sites that do not meet the data completeness criteria as stated in CFR Part 50 3.1(b) An ann ual primary standard design va lue isvalid when at least 75% of the data hours in the y ear are reported Note : The Annual Primary values have not been rounded to the nearest whole number as desCtibed I n CfR Part 50 4 . 1(bJI·Hour Primary NAAQS 3-Y..,98 MonIto,NII,.. ,. SIte ID PwcIntIIe .".,... (ppb)**D"'COmp~** r.,

__el of........ hours ... 

# ............

# ­ ...... '- 15" ............ ...

- .... NAAQSI

14 Total Days = 278 12 Total Days = 323
33 Total Days = 310 38 Total Days = 360

8 Total Days = 246 10 Total Days = 285

for the SUllst.tutlon test Tat Desiln V.lue V ••, 98 Percentile ave,... (ppb)45 40
38

19
22
13
2 Data Source : EPA' s AQS Dat a Completeness Report