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Adequacy Status of Submitted State Implementation Plans (SIP) for Transportation Conformity Purposes: MOBILE6 Motor Vehicle Emissions Budgets for the Houston-Galveston-Brazoria 1-Hour Ozone Nonattainment Area

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Environmental Protection Agency (EPA).


Notice of adequacy determination.


In this notice, EPA is notifying the public that we have found the on-road motor vehicle emissions budgets contained in the revision to the Houston-Galveston-Brazoria severe 1-hour ozone nonattainment area attainment demonstration SIP adequate for transportation conformity purposes. As a result of our finding, the budgets from the submitted attainment demonstration SIP revision must be used for future conformity determinations in the Houston-Galveston-Brazoria area.


These budgets are effective May 9, 2005.

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The essential information in this notice will be available at EPA's conformity Web site:​oms/​transp/​conform/​adequacy.htm. You may also contact Ms. Peggy Wade, Air Planning Section (6PD-L), U.S. EPA Region 6, 1445 Ross Avenue, Dallas, Texas 75202-2733, telephone (214) 665-7247, E-mail address:

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Throughout this document “we,” “us,” and “our” refers to EPA. The word “budget(s)” refers to the mobile source emissions budget for volatile organic compounds (VOCs) and the mobile source emissions budget for nitrogen oxides (NOX). The word “SIP” in this document refers to the State Implementation Plan revision submitted to satisfy the commitment of the State of Texas to revise its mobile source budgets for the Houston-Galveston-Brazoria 1-hour ozone nonattainment area with MOBILE6. (MOBILE6 is the most recent emissions factor model, released by EPA on January 29, 2001.)

In December 2004, we received the MOBILE6 SIP revision for the Houston-Galveston-Brazoria 8-county 1-hour ozone nonattainment area. There are two motor vehicle emissions budgets found in this plan for 2007. The emissions budget for VOCs is 89.99 tons/day; the NOX emissions budget is Start Printed Page 20900186.13 tons/day. On January 12, 2005, the availability of these budgets was posted on EPA's Web site for the purpose of soliciting public comments. The comment period closed on February 11, 2005, and we received no comments.

Today's notice is simply an announcement of a finding that we have already made. EPA Region 6 sent a letter to the Texas Commission on Environmental Quality on March 23, 2005, finding that the motor vehicle emissions budgets in the Houston-Galveston-Brazoria 8-county ozone nonattainment area are adequate and must be used for transportation conformity determinations.

Transportation conformity is required by section 176(c) of the Clean Air Act. EPA's conformity rule, 40 CFR part 93, requires that transportation plans, programs and projects conform to SIPs and establishes the criteria and procedures for determining whether or not they do so. 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 EPA determines whether a SIP's motor vehicle emission budgets are adequate for conformity purposes are outlined in 40 CFR 93.118(e)(4). Please note that such an adequacy review is separate from EPA's completeness review, and it should not be used to prejudge EPA's ultimate approval of 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: April 14, 2005.

Richard E. Greene,

Regional Administrator, Region 6.

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[FR Doc. 05-8122 Filed 4-21-05; 8:45 am]