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Adequacy Determination for the Denver and Longmont, CO, Carbon Monoxide and Denver PM10

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Environmental Protection Agency (EPA).


Notice of adequacy.


With a letter signed September 25, 2006, the State of Colorado submitted revised maintenance plans for carbon monoxide for Denver and Longmont, Colorado, and a revised maintenance plan for PM10 for Denver, Colorado (the “maintenance plans”). In this document, EPA is notifying the public that we have found adequate for transportation conformity purposes the following motor vehicle emissions budgets from the maintenance plans: The 2021 carbon monoxide motor vehicle emissions budget from the Denver carbon monoxide maintenance plan, the 2020 carbon monoxide motor vehicle emissions budget from the Longmont carbon monoxide maintenance plan, and the 2022 PM10 and NOX motor vehicle emissions budgets from the Denver PM10 maintenance plan. 40 CFR 93.118(e)(2) requires that EPA declare an implementation plan submission's motor vehicle emissions budgets adequate for conformity purposes prior to the budgets being used to satisfy the conformity requirements of 40 CFR part 93. As a result of our finding, the Denver Regional Council of Governments as the Metropolitan Planning Organization, the Colorado Department of Transportation and the U.S. Department of Transportation are required to use the motor vehicle emissions budgets identified above for future transportation conformity determinations.


This finding is effective June 28, 2007.

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Jeffrey Kimes, Air & Radiation Program (8P-AR), United States Environmental Protection Agency, Region 8, 1595 Wynkoop, Denver, Colorado 80202, (303) 312-6445,

The letters documenting our finding are available at EPA's conformity Web site:​otaq/​stateresources/​transconf/​reg8sips.htm.

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Throughout this document we, us, or our, are used to mean EPA.

This action is simply an announcement of a finding that we have already made. We sent letters to the State of Colorado, Department of Public Health and Environment on May 3, 2007, stating that the 2021, 2020, and 2022 motor vehicle emissions budgets (MVEB) in the submitted Denver and Longmont carbon monoxide maintenance plans and the Denver PM10 maintenance plan are adequate. These findings will also be announced on our conformity Web site at​otaq/​stateresources/​transconf/​reg8sips.htm.

Transportation conformity is required by section 176(c) of the Clean Air Act. The conformity rules at 40 CFR part 93 require that transportation plans, programs, and projects conform to SIPs and establish the criteria and procedures for determining whether or not they demonstrate conformity. 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 MVEBs are adequate for conformity purposes are outlined in 40 CFR 93.118(e)(4). Please note that an adequacy review is separate from our completeness review, and it also should not be used to prejudge our ultimate approval of the SIP. Even if we find a budget adequate, the SIP could later be disapproved, and vice versa.

The process for determining the adequacy of a transportation conformity budget is described at 40 CFR 93.118(f).

The 2021, 2020, and 2022 MVEBs from the Denver and Longmont, Colorado carbon monoxide and PM10 maintenance plans are as follows: Start Printed Page 32647

Carbon Monoxide

YearMaintenance areaPollutantEmission budget (tons per day)
2021DenverCarbon Monoxide1600
2020LongmontCarbon Monoxide43


YearMaintenance areaPollutantEmission budget (tons per day)
2022DenverNitrogen Oxides (NOX)56

40 CFR 93.118(e)(1) requires that upon a finding of adequacy these budgets must be used in transportation conformity determinations unless the maintenance plan is later disapproved by EPA.

We note that the submitted Denver, Colorado, carbon monoxide maintenance plan proposes revisions to the previously approved 2013 carbon monoxide MVEB for Denver. The submitted Longmont, Colorado, carbon monoxide maintenance plan proposes changes to the previously approved 2010 and 2015 carbon monoxide MVEBs for Longmont. The submitted Denver, Colorado, PM10 maintenance plan proposes changes to the previously approved 2015 PM10 and NOX MVEBs for Denver. However, 40 CFR 93.118 (e)(1) does not allow budgets in submitted plans to supersede MVEBs in approved implementation plans for the same Clean Air Act requirement and the same years addressed by a previously approved implementation plan unless EPA specifies otherwise in its approval of a SIP, a circumstance that does not apply here. Thus, this adequacy finding does not make any changes to these previously approved budgets. These budgets will be addressed in EPA's action regarding the approval or disapproval of the maintenance plans.

The submitted Denver PM10 maintenance plan includes a budget trading protocol for calculating the PM10 and NOX budgets for each conformity determination. That protocol will be addressed in EPA's action to approve or disapprove the maintenance plan; this adequacy finding has no bearing on that action and does not authorize the use of the budget trading protocol.

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

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Dated: June 1, 2007.

Kerrigan G. Clough,

Acting Regional Administrator, Region 8.

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[FR Doc. E7-11413 Filed 6-12-07; 8:45 am]