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Adequacy Status of the Greensboro/Winston-Salem/Highpoint North Carolina 1997 Annual PM2.5

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Environmental Protection Agency (EPA).


Notice of Adequacy.


In this notice, EPA is notifying the public of its finding that the direct fine particulate (PM2.5) and nitrogen oxides (NOX) motor vehicle emissions budgets (MVEBs) in the Greensboro/Winston-Salem/Highpoint, North Carolina area (hereafter referred to as “the Triad Area”) maintenance plan for the 1997 annual PM2.5 standard, submitted on December 18, 2009, and supplemented on December 22, 2010, by the North Carolina Department of Environment and Natural Resources (NCDENR) are adequate for transportation conformity purposes. The Triad Area is comprised of Guilford and Davidson Counties in their entirety. On March 2, 1999, the District of Columbia Circuit Court ruled that submitted state implementation plans (SIPs) cannot be used for transportation conformity determinations until EPA has affirmatively found them adequate. As a result of EPA's finding, the Triad Area must use the PM2.5 and NOX MVEBs from the submitted maintenance plan for the Area for future conformity determinations.


The adequacy finding for the PM2.5 and NOX MVEBs are effective May 17, 2011.

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Dianna B. Smith, Environmental Scientist, U.S. Environmental Protection Agency, Region 4, Air Planning Branch, Air Quality Modeling and Transportation Section, 61 Forsyth Street, SW., Atlanta, Georgia 30303. Ms. Smith can also be reached by telephone at (404) 562-9207, or via electronic mail at The finding is available at EPA's conformity Web site:​otaq/​transp.htm (once there, click on the “Transportation Conformity” text icon, then look for “Adequacy Review of SIP Submissions”).

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Today's notice is simply an announcement of findings that EPA has already made. EPA Region 4 sent a letter to NCDENR on February 2, 2011, stating that the 2011 and 2021 sub-area PM2.5 and NOx MVEBs in the 1997 PM2.5 maintenance plan for the Triad Area, dated December 18, 2009, and supplemented on December 22, 2010, are adequate. EPA posted the availability of the Triad MVEBs on EPA's Web site on November 23, 2010, as part of the adequacy process, for the purpose of soliciting comments. The comment period ran from November 23 through December 23, 2010. EPA's findings have also been announced on EPA's conformity Web site:​otaq/​stateresources/​index.htm, (once there, click “Transportation Conformity” text icon, then look for “Adequacy Review of SIP Submissions”). The adequate PM2.5 and NOX MVEBs are provided in the following table:

Triad, North Carolina Annual PM2.5 MVEBS


Guilford County Sub-area MVEB
Davidson County Sub-area MVEB

Transportation conformity is required by section 176(c) of the Clean Air Act, as amended in 1990. EPA's conformity rule, 40 Code of Federal Regulations (CFR) Part 93, requires that transportation plans, programs and projects conform to state air quality implementation plans and establishes the criteria and procedures for determining whether or not they do. 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 (NAAQS).

The criteria by which EPA determines whether a SIP's MVEBs are adequate for transportation conformity purposes are outlined in 40 CFR 93.118(e)(4). EPA has described the process for determining the adequacy of submitted SIP budgets in a May 14, 1999, memorandum entitled “Conformity Guidance on Implementation of March 2, 1999 Conformity Court Decision.” EPA has followed this guidance in making this adequacy determination. This guidance is incorporated into EPA's July 1, 2004, final rulemaking entitled “Transportation Conformity Rule Amendments for the New 8-hour Ozone and PM2.5 National Ambient Air Quality Standards and Miscellaneous Revisions for Existing Areas; Transportation Conformity Rule Amendments: Response to Court Decision and Additional Rule Changes” (69 FR 40004). Please note that an adequacy review is separate from EPA's completeness review, and it also should not be used to prejudge EPA's ultimate approval of the SIP. Even if EPA finds the MVEB adequate, the Agency may later disapprove the SIP.

Within 24 months from the effective date of this notice, the transportation Start Printed Page 24475partners will need to demonstrate conformity to the new MVEB if the demonstration has not already been made, pursuant to 40 CFR 93.104(e). See 73 FR 4419 (January 24, 2008).

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

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Dated: April 18, 2011.

A. Stanley Meiburg,

Acting Regional Administrator, Region 4.

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[FR Doc. 2011-10564 Filed 4-29-11; 8:45 am]