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Adequacy Status of Motor Vehicle Budget in Submitted Five Percent Plan for PM-10 for the Phoenix Metropolitan Nonattainment Area for Transportation Conformity Purposes; Arizona

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Environmental Protection Agency (EPA).


Notice of Adequacy.


In this notice, EPA is notifying the public that the Agency has found that the motor vehicle emissions budget in the submitted MAG 2007 Five Percent Plan for PM-10 for the Maricopa County Nonattainment Area (December 2007) (“2007 MAG 5% Plan”) is adequate for transportation conformity purposes. The 2007 MAG 5% Plan was submitted to EPA on December 21, 2007 by the Arizona Department of Environmental Quality as a revision to the Arizona state implementation plan. The 2007 MAG 5% Plan includes a demonstration of no less than five percent annual emissions reductions in particulate matter with an aerodynamic diameter less than or equal to a nominal 10 micrometers (PM-10) and a demonstration of PM-10 attainment in the Phoenix metropolitan area by 2010. As a result of our finding, the Maricopa Association of Governments and the U.S. Department of Transportation must use the motor vehicle emissions budget from the submitted five percent plan for PM-10 for future conformity determinations.


This finding is effective July 1, 2008.

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Wienke Tax, U.S. EPA, Region IX, Air Start Printed Page 34014Division AIR-2, 75 Hawthorne Street, San Francisco, CA 94105-3901; (520) 622-1622 or

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Throughout this document, whenever “we,” “us,” or “our” is used, we mean EPA.

Today's notice is simply an announcement of a finding that we have already made. EPA Region IX sent a letter to the Arizona Department of Environmental Quality and the Maricopa Association of Governments on May 30, 2008 stating that the 2010 motor vehicle emissions budget for PM-10 in the submitted 2007 MAG 5% Plan is adequate. The budget corresponds to the Phoenix metropolitan PM-10 nonattainment area, which encompasses roughly half of Maricopa County, including the cities of Phoenix and Mesa, and also the Apache Junction area of Pinal County, in central Arizona. Receipt of this motor vehicle emissions budget was announced on EPA's transportation conformity Web site, and no comments were submitted. The finding is available at EPA's conformity Web site:​otaq/​stateresources/​transconf/​adequacy.htm.

The adequate 2010 motor vehicle emissions budget (calculated for an annual average day) are provided in the following table:

Adequate Motor Vehicle Emissions Budget

[In metric tons per day]

Budget yearPM-10 motor vehicle emissions budget

Transportation conformity is required by Clean Air Act section 176(c). EPA's conformity rule requires that transportation plans, transportation improvement programs, and projects conform to state air quality implementation plans (SIPs) and establishes the criteria and procedures for determining whether or not they do conform. Conformity to a SIP means that transportation activities will not produce new air quality violations, worsen existing violations, or delay timely attainment of the national ambient air quality standards.

The criteria by which we determine whether a SIP's motor vehicle emissions budgets are adequate for conformity purposes are outlined in 40 CFR 93.118(e)(4). We have described our process for determining the adequacy of submitted SIP budgets in our July 1, 2004, preamble starting at 69 FR 40038, and we used the information in these resources while making our adequacy determination. Please note that an adequacy review is separate from EPA's completeness review, and should not be used to prejudge EPA's ultimate approval action for the SIP. Even if we find a budget adequate, the SIP could later be disapproved.

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Authority: 42 U.S.C. 7401 et seq.

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Dated: June 5, 2008.

Laura Yoshii,

Acting Regional Administrator, Region IX.

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[FR Doc. E8-13519 Filed 6-13-08; 8:45 am]