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Adequacy Status of the Alabama Portion (Jackson County) of the Chattanooga, Tennessee Tri-State Area 1997 Annual PM2.5

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Environmental Protection Agency (EPA).


Notice of Adequacy.


In this notice, EPA is notifying the public that EPA has made an insignificance finding through the transportation conformity adequacy Start Printed Page 34736process for directly emitted fine particulate matter (PM2.5) and nitrogen oxides (NOX) emissions as contained in the 1997 PM2.5 attainment demonstration for the Alabama portion of the tri-state Chattanooga, Tennessee nonattainment area (hereafter referred to as the “Jackson County Area”). On October 14, 2009, the State of Alabama, through the Alabama Department of Environmental Management (ADEM), submitted an attainment demonstration plan for the 1997 annual PM2.5 standard for Jackson County, Alabama as part of the tri-state Chattanooga 1997 PM2.5 nonattainment area. The tri-state Chattanooga 1997 annual PM2.5 nonattainment area is comprised of a portion of Jackson County, Alabama; Catoosa and Walker Counties, Georgia; and Hamilton County, Tennessee. As a result of EPA's finding, the portion of Jackson County within the tri-state Chattanooga 1997 PM2.5 nonattainment area is no longer required to perform a regional emissions analysis for either directly emitted PM2.5 or NOX as part of future PM2.5 conformity determinations for the 1997 annual PM2.5 standard. This finding only relates to the Alabama portion of this Area, and does not relieve the Georgia or Tennessee portions of the tri-state 1997 PM2.5 nonattainment area from the requirement of performing the regional emissions analyses for direct PM2.5 and NOX. EPA will review the adequacy of the Georgia and Tennessee submittals with regard to the motor vehicle emission budgets or insignificance findings (if any and if appropriate) in separate actions.


This insignificance finding for direct PM2.5 and NOX is effective July 6, 2010.

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Dianna 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/​stateresources/​transconf/​adequacy.htm

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This notice is simply an announcement of a finding that EPA has already made. EPA Region 4 sent a letter to ADEM on March 25, 2010, stating that regional mobile source emissions of direct PM2.5 and NOX emissions are insignificant as provided in the Alabama portion of the 1997 annual PM2.5 attainment demonstration for the Jackson County Area submitted on October 14, 2009. EPA posted the availability of the insignificance finding on EPA's Web site on February 16, 2010, as part of the adequacy process, for the purpose of soliciting comments. The comment period ran from February 16, 2010, through March 18, 2010. During EPA's adequacy comment period, no comments were received on the insignificance finding for the Jackson County Area. Through this notice, EPA is informing the public of the insignificance finding for direct PM2.5 and NOX for the purpose of implementing transportation conformity in the Jackson County Area for the 1997 PM2.5 standard. EPA's findings have also been announced on EPA's conformity Web site:​otaq/​stateresources/​transconf/​adequacy.htm.

Transportation conformity is required by section 176(c) of the Clean Air Act, as amended in 1990. EPA's conformity rule 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. 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.

The criteria by which EPA determines whether a SIP's motor vehicle emissions budget is adequate for transportation conformity purposes are outlined in 40 Code of Federal Regulations (CFR) 93.118(e)(4). The Transportation Conformity Rule in 40 CFR 93.109(k) states that a regional emissions analysis is no longer necessary if EPA finds through the adequacy or approval process that a SIP demonstrates that regional motor vehicle emissions are an insignificant contributor to the air quality problem for that pollutant/precursor. A finding of insignificance does not change the requirement for a regional analysis for other pollutants/precursors and does not change the requirement for hot-spot analysis. (See 73 FR 4419, January 24, 2008.) 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 attainment demonstration plan for the Jackson County Area. Even if EPA finds the insignificance determination adequate, the attainment demonstration plan could later be disapproved.

Transportation partners should note this insignificance finding in future transportation conformity determinations. Additionally, while this insignificance finding waives the requirements for regional emissions analyses for direct PM2.5 and NOX for the Jackson County Area for the 1997 PM2.5 standard, as mentioned above, it does not waive other conformity requirements for the 1997 PM2.5 standard for the Jackson County Area, nor does it waive transportation conformity requirements for other pollutants/precursors for which the Area may be designated nonattainment or redesignated to attainment with a maintenance plan.

EPA has described the process for determining the adequacy of submitted SIP budgets (which also applies to insignificance determinations) 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).

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

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Dated: June 8, 2010.

Beverly H. Banister,

Acting Regional Administrator, Region 4.

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[FR Doc. 2010-14770 Filed 6-17-10; 8:45 am]