2018-05406. Adequacy Determination for the Denver-North Front Range 2008 Ozone Attainment Plan's Motor Vehicle Emissions Budgets for Transportation Conformity Purposes; State of Colorado

AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Notice of adequacy determination.

SUMMARY:

In this notice, the Environmental Protection Agency (EPA) is notifying the public that the EPA has found the Metro-Denver/North Front Range (Metro-Denver/NFR) Moderate 2008 8-hour ozone National Ambient Air Quality Standard (NAAQS) attainment plan and its motor vehicle emissions budgets (MVEBs) adequate for transportation conformity purposes. As more fully explained in the Supplementary Information section of this notice, this finding will affect future transportation conformity determinations.

DATES:

This finding is effective on April 2, 2018.

FOR FURTHER INFORMATION CONTACT:

Tim Russ, Air Program, U.S. Environmental Protection Agency, Region 8, Mailcode 8P-AR, 1595 Wynkoop Street, Denver, Colorado 80202-1129, [phone], or [e-mail].

SUPPLEMENTARY INFORMATION:

Transportation conformity is required by section 176(c) of the Clean Air Act to ensure that federally funded highway and transit projects are consistent with the air quality goals established by the state implementation plan (SIP). The EPA's conformity rule provisions at 40 CFR part 93, subpart A, establish the criteria and procedures for determining whether transportation plans, programs and projects conform to the SIP. Conformity to a SIP means that transportation activities will not produce new air quality violations, worsen existing violations, or delay timely attainment of the applicable NAAQS.

The criteria by which the EPA determines whether a SIP revision's MVEBs are adequate for transportation conformity purposes are outlined at 40 CFR 93.118(e)(4), and the adequacy review process is described at 40 CFR 93.118(f)(1). We applied these criteria and followed this process in making the determinations announced in this notice.

This notice is simply an announcement of findings that the EPA has already made, as described below.

The State of Colorado submitted the Metro-Denver/NFR Moderate 2008 8-hour ozone NAAQS attainment plan, and its associated MVEBs, on May 16, 2017. As part of our adequacy review, we posted the Metro-Denver/NFR Moderate 2008 8-hour ozone NAAQS attainment plan, with its identified nitrogen oxides (NO_X) and volatile organic compounds (VOC) MVEBs, for adequacy review on the EPA Office of Transportation and Air Quality's transportation conformity website (https://www.epa.gov/​state-and-local-transportation/​adequacy-review-state-implementation-plan-sip-submissions-conformity) on December 8, 2017. The EPA requested public comments by January 8, 2018; we did not receive any comments. We sent a letter to the Colorado Department of Public Health and Environment (CDPHE) on January 30, 2018, stating that the submitted Metro-Denver/NFR Moderate 2008 8-hour ozone NAAQS attainment plan and its MVEBs were adequate for transportation conformity purposes.

For the Metro-Denver/NFR Moderate 2008 8-hour ozone NAAQS attainment plan, the MVEBs we found adequate were as identified and described in Chapter 11 of the ozone attainment plan. We find that the Total Nonattainment Area Budgets of 73 tons per day (tpd) of NO_X and 55 tpd of VOC for 2017 are adequate, in accordance with 40 CFR 93.118. We also find the nonattainment area's Northern Subarea Budgets of 12 tpd of NO_X and 8 tpd of VOCs and the Southern Subarea Budgets of 61 tpd of NO_X and 47 tpd of VOCs, all for 2017, are adequate.

In addition, and as described in Chapter 11 of the Metro-Denver/NFR Moderate 2008 8-hour NAAQS ozone attainment plan, the Denver Regional Council of Governments (DRCOG) Metropolitan Planning Organization (MPO) and the North Front Range MPO (NFRMPO) may switch from using the combined nonattainment-area-wide MVEBs to using the sub-area MVEBs for determining transportation conformity. To switch to use of the sub-area MVEBs (or to subsequently switch back to use of the combined nonattainment-area-wide MVEBs), the DRCOG and the NFRMPO must use the process described in Chapter 11 of the Metro-Denver/NFR ozone Moderate 2008 8-hour NAAQS ozone attainment plan on pages 11-5 through 11-6.

Following the effective date listed in the DATES section of this notice, the DRCOG, the NFRMPO, the Colorado Department of Transportation, and the U.S. Department of Transportation are required to use the MVEBs discussed above for future transportation conformity determinations for projects in the Metro-Denver/NFR Moderate 2008 8-hour NAAQS ozone nonattainment area. Please refer to 40 CFR 81.306 for a description of the nonattainment area boundary. On the effective date of this notice of adequacy, the previously-approved NO_X and VOC MVEBs (76 FR 47443; August 5, 2011) for the Metro-Denver/NFR 1997 8-hour ozone NAAQS nonattainment area will no longer be applicable for transportation conformity purposes.

Please note that our adequacy review of the MVEBs is separate from our future rulemaking action on the Metro-Denver/NFR Moderate 2008 8-hour NAAQS ozone attainment plan SIP revision and should not be used to prejudge our ultimate approval or disapproval of that SIP revision. Even if we find the Metro-Denver/NFR Moderate 2008 8-hour NAAQS ozone attainment plan and its MVEBs adequate for transportation conformity purposes now, we may later find it necessary to disapprove the SIP revision. Should this situation arise, we would revisit our adequacy finding.

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

Dated: March 13, 2018.

Douglas H. Benevento,

Regional Administrator, Region 8.