STATE OF UTAH 

MICHAELO . LEAVIT T OFFIC E O F TH E GOVERNO R OLEN E S. WALKE R 

GOVERNO R SAL T LAK E CIT Y LIEUTENAN T GOVERNO R 

£ 4 1 14-060 1 

July 3, 2002 

Robert E. Roberts 

Regional Administrator 

EPA Region VIII 

999 18th Street - Suite 500 

Denver, Colorado 80202-2405 

Dear Mr. Roberts: 

Re: PM10 SIP Revision - Utah County 

On July 3, 2002, the Utah Air Quality Board approved a revision to the State Implementation Plan 

(SIP) for PM10 in Utah County. At the conclusion of the State's administrative process, the revision will 

become State law. The effective date will be September 1, 2002. 

The primary objective of this SIP revision was to facilitate a positive finding of transportation 

conformity in Utah County. Recognizing that such finding must be based on a federally approved SIP, we 

have worked extensively with your staff, and now request that this submittal be processed as expeditiously as 

possible. 

Enclosed, are two copies of each of the following: 1) Utah State Implementation Plan Section IX Part 

A, Fine Particulate Matter (PM10), Utah County; 2) revisions to Utah State Implementation Plan Section IX 

Part H. 1, Emission Limits, Utah County; and 3) Supplement 11-02 to the Technical Support Document for the 

PM10 SIP. 

Please contact Rick Sprott, Director, Division of Air Quality, at 801-536-0072, regarding further 

information or questions concerning this submittal. 

Sincerely. 

Michael O. Leavitt 

Governor 

MOL:DRN:dco 

cc: Rick Sprott 
IX.A.7 MAINTENANCE 

With this revision to the PM1 0 SIP, the Utah Air Quality Board commits to developing a PM1 ( 

maintenance plan or SIP revision, as appropriate, based on dispersion modeling. 

IX.A.8 CONTINGENCY MEASURES 

IX.A.8.a. Attainment Date 

On 18 June 2001, EPA published a finding (66 FR 32752) that Salt Lake County had 

attained the NAAQS by 31 December 1995 and Utah County had attained the NAAQS by 

31 December 1996. That notice also stated that both areas had demonstrated Reasonable 

Further Progress as required in the Act (66 FR 32752-754). A letter from EPA Region VIII 

to the Division of Air Quality dated October 6, 2000 stated that, "In an October 6, 1995 

memorandum from Joe Paisie of OAQPS to the EPA regional offices, it was explained that 

if a PM1 0 nonattainment area has attained the standard with at least 3 years of clean air 

quality data, and as long as that area continues to attain the standard, the section 

172(c)(9) contingency measure requirement will not apply." Therefore, with eight years of 

clean air quality data, Utah is not required to submit contingency measures in this SIP. 

Copies of the Joe Paisie memorandum and the October 6, 2000 letter from EPA to UDAQ 

are contained in Supplement II-02 of the TSD. 

IX.A.9 ANNUAL AVERAGE 

DEMONSTRATION OF ATTAINMENT OF THE ANNUAL AVERAGE 

The application of many of the control strategies that are being implemented to 

reduce the 24-hour PM1 0 concentrations will also result in a reduction of the annual PM1 0 

concentrations even though they are designed to reduce winter time 24-hour 

concentrations. Table 9.A.26 shows that the winter season is the period that has the 

greatest impact on the annual average and controlling PM1 0 concentrations during the 

winter will have the greatest impact on the annual average. 

Design values in Utah County ranged from 191 //g/m3 to 264 /vg/m3. Thus, the 

control strategy necessary to achieve the 24-hr NAAQS at all stations effectively ranges 

from 27% to 43%. Even the minimum of this range is well in excess of the 7.4% necessary 

to bring the maximum observed annual concentration back down to the level of the annual 

standard. The annual NAAQS for PM1 0 was never violated in Utah County. 

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