Adequacy Status of Post-Attainment Year Motor Vehicle Emissions Budgets in 2006 PM2.5

AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Notice of adequacy.

SUMMARY:

The Environmental Protection Agency (EPA) is notifying the public that the Agency has found that the motor vehicle emissions budgets (“budgets”) for the year 2020 in the 2016 Air Quality Management Plan (AQMP) for the 2006 fine particulate matter (PM_2.5) National Ambient Air Quality Standards (NAAQS) in the Los Angeles-South Coast Air Basin “Serious” nonattainment area (“South Coast 2006 PM_2.5 Serious Area Plan”) are adequate for transportation conformity purposes. The California Air Resources Board (CARB) submitted the South Coast 2006 PM_2.5 Serious Area Plan to the EPA on April 27, 2017, as a revision to the California State Implementation Plan (SIP). Upon the effective date of this notice of adequacy, the Southern California Association of Governments (SCAG) and the U.S. Department of Transportation (DOT) must use the adequate budgets in future transportation conformity analyses.

DATES:

This finding is effective October 28, 2021.

FOR FURTHER INFORMATION CONTACT:

Ginger Vagenas, EPA, Region IX, Air Division AIR-2, 75 Hawthorne Street, San Francisco, CA 94105-3901; (415) 972-3964 or vagenas.ginger@epa.gov.

SUPPLEMENTARY INFORMATION:

Throughout this document, whenever “we,” “us,” or “our” is used, we mean the EPA.

Today's notice is simply an announcement of a finding that we have already made. By letter dated September 28, 2021, EPA Region IX notified CARB that the budgets in the South Coast 2006 PM_2.5 Serious Area Plan for the reasonable further progress (RFP) post-attainment milestone year of 2020 are adequate. The finding is available at EPA's conformity website: https://www.epa.gov/state-and-local-transportation/conformity-adequacy-review-region-9. We announced the availability of the South Coast 2006 PM_2.5 Serious Area Plan and related 2020 budgets on the EPA's transportation conformity website on April 16, 2021. We received no comments in response to the adequacy review posting. The adequate motor vehicle emissions budgets are provided in the following table:

Transportation conformity is required by Clean Air Act section 176(c). The EPA's conformity rule requires that transportation plans, transportation improvement programs, and projects conform to SIPs and establishes the criteria and procedures for determining whether or not they do conform. Conformity to a SIP means that transportation activities will not produce new air quality violations, worsen existing violations, or delay timely attainment of the NAAQS.

The criteria by which we determine whether a SIP's budgets are adequate for conformity purposes are outlined in 40 CFR 93.118(e)(4), which was promulgated in our August 15, 1997 final rule. We further described our process for determining the adequacy of submitted SIP budgets in our July 1, 2004 final rule and we used the information in these resources in making the adequacy determination announced in this notice.

The EPA approved the South Coast 2006 PM_2.5 Serious Area Plan on February 12, 2019. In that action, we approved the budgets for the 2017 RFP year and the 2019 attainment year. We also approved a trading mechanism for transportation conformity analyses that allows future decreases in NO_X from on-road mobile sources to offset any on-road increases in PM_2.5 , based on specified trading ratios. The South Coast Air Quality Management District (SCAQMD) indicated that the trading mechanism was included in the 2016 AQMP for approval by the EPA for use by SCAG in conformity determinations for the 2006 PM_2.5 NAAQS for analysis years after the attainment year of 2019.

Consistent with the requirements set out in our implementation rule for the PM_2.5 NAAQS, we did not act on the RFP budget for the post-attainment year of 2020 when we approved the South Coast 2006 PM_2.5 Serious Area Plan. As we noted in our proposed approval of the South Coast 2006 PM_2.5 Serious Area Plan, it is not necessary to demonstrate conformity for 2020 or to use the 2020 budgets until such time as the area fails to attain the 2006 24-hour PM_2.5 NAAQS.

On September 16, 2020, the EPA determined that the Los Angeles-South Coast Air Basin had failed to attain the 2006 24-hour PM_2.5 NAAQS by its December 31, 2019 attainment date. Because of that failure to attain, we evaluated the submitted budgets for 2020 in the South Coast 2006 PM_2.5 Serious Area Plan to determine whether they are adequate for conformity purposes.

Pursuant to 40 CFR 93.104(e), within two years of the effective date of this notice, SCAG and the DOT will need to demonstrate conformity. For demonstrating conformity to the budgets in this plan, the on-road motor vehicle emissions from implementation of the transportation plan or program should be projected consistently with the budgets in this plan, i.e., by taking the emissions results derived from CARB's EMFAC model (short for EMission FACtor) and then rounding the emissions up to the nearest ton. The previously approved trading mechanism may be used in connection with the new budgets.

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