Clean Air Plans; Contingency Measures for the Fine Particulate Matter Standards; San Joaquin Valley, California

SUPPLEMENTARY INFORMATION:

Throughout this document, “we,” “us” and “our” refer to the EPA.

Table of Contents

I. Background

A. Proposed Action

B. Changes to Proposed Action

II. Public Comments and EPA Responses

III. Environmental Justice Considerations

IV. EPA Action

V. Incorporation by Reference

VI. Statutory and Executive Order Reviews

I. Background

A. Proposed Action

On December 20, 2023 (88 Federal Register (FR) 87988), the EPA proposed to approve California's contingency measure SIP submissions for the 1997 annual, 2006 24-hour, and 2012 annual PM_2.5 NAAQS submitted by the California Air Resources Board (CARB) for the San Joaquin Valley nonattainment area in California. Specifically, the SIP submissions include the “PM_2.5 Contingency Measure State Implementation Plan Revision (May 18, 2023)” (herein referred to as the “SJV PM_2.5 Contingency Measure SIP”), revisions to San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD or “District”) Rule 4901 (amended May 18, 2023) that add PM_2.5 NAAQS contingency provisions that we refer to herein as the “Residential Wood Burning Contingency Measure,” and revisions to Rule 8051 (amended September 21, 2023) that add PM_2.5 NAAQS contingency provisions that we refer to herein as the “Rural Open Areas Contingency Measure.” CARB submitted the SJV PM_2.5 Contingency Measure SIP and the Residential Wood Burning Contingency Measure on June 8, 2023, and the Rural Open Areas Contingency Measure on October 16, 2023, as revisions to the California SIP.

In addition, in a separate proposed rule also published on December 20, 2023, the EPA proposed approval of a third contingency measure, applicable to light-duty on-road motor vehicles, and the related emission reductions from the third measure are accounted for in this final rule. We refer to the third contingency measure as the “Smog Check Contingency Measure.”

We proposed to approve the SJV PM_2.5 Contingency Measure SIP, the Residential Wood Burning Contingency Measure, and the Rural Open Areas Contingency Measure because we determined that they, along with emission reductions from the Smog Check Contingency Measure, comply with the contingency measure SIP requirements of CAA section 172(c)(9) and EPA's implementing regulations at 40 CFR 51.1014. We collectively refer herein to CARB's contingency measure SIP submissions for the 1997 annual, 2006 24-hour, and 2012 annual PM_2.5 NAAQS for the San Joaquin Valley as the State's “2023 SIP Submissions.”

In sections I and II of the proposed rule, we presented background information on the 1997 annual and 24-hour, the 2006 24-hour and 2012 annual PM_2.5 NAAQS, the nonattainment designations and classifications of the San Joaquin Valley for these PM_2.5 NAAQS, and the resultant contingency measure SIP obligations; summarized our prior PM_2.5 contingency measure findings of failure to submit and disapprovals for the San Joaquin Valley; described the SIP submissions at issue in this action; and provided the basis for our preliminary conclusion that the SIP submissions met applicable procedural requirements. In section III of the proposed rule, we summarized the contingency measure SIP requirements under the CAA and the EPA's implementing regulations, relevant EPA guidance, and legal precedent, including a brief discussion of relevant decisions by the Ninth Circuit Court of Appeals and the D.C. Circuit Court of Appeals.

In addition, we described the EPA's long-standing approach to contingency measures and the EPA's revised approach for addressing the contingency measure SIP requirements, as presented in the EPA's draft guidance, entitled “Draft: Guidance on the Preparation of State Implementation Plan Provisions that Address the Nonattainment Area Contingency Measure Requirements for Ozone and Particulate Matter (DRAFT—3/17/23—Public Review Version),” herein referred to as the “Draft Revised Contingency Measure Guidance.” Two principal differences between the draft revised guidance and existing guidance on contingency measures relate to the EPA's recommendations concerning the specific amount of emission reductions that implementation of contingency measures should achieve and the timing for when the emission reductions from the contingency measures should occur. The Draft Revised Contingency Measure Guidance also provides recommended procedures for developing a demonstration, if applicable, that the area lacks sufficient feasible measures to achieve one year's worth (OYW) of reductions, building on existing guidance that the state should provide a reasoned justification for why the smaller amount of emission reductions is appropriate.

In section IV of the proposed rule, we described the two specific District PM_2.5 contingency measures proposed for approval in this action ( i.e., the District's Residential Wood Burning Contingency Measure and Rural Open Areas Contingency Measure) and provided our evaluation of the measures relative to the requirements of CAA section 172(c)(9) and 40 CFR 51.1014. In short, we preliminarily concluded that the contingency measures met the requirements for such measures because both measures are designed to be both prospective and conditional, include appropriate triggering mechanisms for requirements, and are structured to be implemented in a timely manner without significant further action by the District, CARB, or the EPA and to achieve the estimated emission reductions within roughly a year or two of the triggering event. Furthermore, both requirements that would be triggered are not required for any other CAA purpose, and the emission reductions from the measures are not included in any reasonable further progress (RFP) or attainment demonstration for the PM_2.5 NAAQS in the San Joaquin Valley. For these reasons, we proposed to approve District's Residential Wood Burning Contingency Measure and Rural Open Areas Contingency Measure.

In section V of the proposed rule, we summarized how the District and CARB had applied the revised approach to fulfilling the contingency measure SIP requirement in the context of the PM_2.5 NAAQS in the San Joaquin Valley, and we presented our evaluation thereof. Specifically, we discussed our evaluation of the District's and CARB's identification and evaluation of potential control measures, adoption of certain contingency measures, comparison of those contingency measures against OYW of emission reductions, and reasoned justification for not adopting further contingency measures, which we recap in the following paragraphs.

In the SJV PM_2.5 Contingency Measure SIP, the District described its ongoing stationary source regulatory efforts, identified potential control measures as candidate contingency measures, and analyzed the technological and/or economic feasibility of each candidate measure, including the feasibility of implementing such measures within 60 days and achieving the resulting emission reductions within one to two years of the triggering event. The District also provided more in-depth analysis of potential control measures for five source categories, ultimately adopting measures for two source categories (wood burning fireplaces/heaters and rural open areas) and providing a justification in the form of an infeasibility demonstration for not adopting contingency measures for the other three source categories (commercial charbroiling, almond harvesting, and oil and gas production combustion equipment).

Similarly, CARB identified potential mobile source control measures, assessed whether each candidate measure could be implemented within 60 days of a triggering event and achieve emission reductions within one to two years, and then analyzed their technological and/or economic feasibility. Regarding timing of emission reductions from mobile sources, CARB concluded that new engine standards and fleet regulations are not appropriate for contingency measures given the time needed for manufacturers to design, develop, and deploy cleaner engines or equipment at scale, especially for zero-emission equipment.

The District and CARB ultimately adopted three contingency measures identified through their respective evaluation processes: the Residential Wood Burning Contingency Measure, the Rural Open Areas Contingency Measure, and the Smog Check Contingency Measure. Each of these measures can be implemented without further action by the District, CARB, or the EPA and achieve emission reductions within one to two years of the triggering event, consistent with the contingency measure requirements under CAA section 172(c)(9) and the EPA's recommendations regarding timing in the Draft Revised Contingency Measures Guidance. In addition, the revisions to SJVUAPCD Rule 4901 establishing the Residential Wood Burning Contingency Measure resolved deficiencies identified in the EPA's disapproval of prior contingency provisions in Rule 4901, thereby ensuring that the direct PM_2.5 and NO_X emission reductions will be achieved, irrespective of which county may exceed the applicable PM_2.5 NAAQS at the time of any finding of failure to attain or other applicable determination.

The District then assessed how the emission reductions from the Residential Wood Burning Contingency Measure would compare against OYW of progress as defined in the Draft Revised Contingency Measure Guidance. As part of our evaluation and for the proposed rule, we prepared an independent assessment of the emission reductions to include the two additional contingency measures that were adopted and submitted after the submission of the SJV PM_2.5 Contingency Measure SIP and to provide a comparison of the emission reductions relative to OYW of progress to the long-standing recommendation of OYW of RFP. In our proposed rule, we found that the combined 0.5873 tons per day (tpd) of direct PM_2.5 emission reductions from the District contingency measures (for residential wood burning and for rural open areas) would exceed both OYW of RFP (0.44-0.58 tpd, depending on the applicable PM_2.5 NAAQS) and OYW of progress (0.41-0.52 tpd, depending on the applicable PM_2.5 NAAQS).

With respect to NO_X emissions, the combined 0.1647-0.1977 tpd emission reductions from all three contingency measures would provide a portion of the reductions toward OYW of emission reductions and, after consideration of interpollutant trading of excess direct PM_2.5 emission reductions from the two District contingency measures for equivalent NO_X emission reductions, would amount to 1.3 percent (%) to 6.3% of OYW of RFP or 8.8% to 15.7% of OYW of progress for NO_X .

As the NO_X emission reductions fall short of OYW of progress, CARB and the District documented their control measure analyses across the wide range of source categories under each agency's respective jurisdiction ( e.g., on-road sources, off-road sources, stationary point sources, and area sources) for NO_X emissions. We described the District's and CARB's infeasibility demonstrations, and our evaluation thereof, in detail and proposed that they adequately justify the contingency measures selected by CARB and the District for the 1997 annual, 2006 24-hour, and 2012 annual PM_2.5 NAAQS in the San Joaquin Valley. In light of the three adopted contingency measures and reasoned justifications for not adopting additional contingency measures, we proposed to approve the SJV PM_2.5 Contingency Measure SIP, the Residential Wood Burning Contingency Measure, and the Rural Open Areas Contingency Measure, taking into account the emission reductions from the Smog Check Contingency Measure (as applied to the San Joaquin Valley), as meeting the contingency measure requirements of CAA section 172(c)(9) and 40 CFR 51.1014 for these PM_2.5 NAAQS in the San Joaquin Valley.

See our December 20, 2023 proposed rule (88 FR 87988) for more information on the SIP submissions and our evaluation thereof.

B. Changes to Proposed Action

In our proposed rule, we evaluated the SIP submissions for compliance with contingency measure SIP requirements, in part, by comparing the emission reductions from the contingency measures with OYW of progress and OYW of RFP. In so doing, we relied on emissions estimates for the three individual contingency measures—two (the Residential Wood Burning Contingency Measure and the Rural Open Areas Contingency Measure) that we proposed to approve in the proposed rule (and that we are finalizing in this action) and one (the Smog Check Contingency Measure) that we proposed to approve in a separate action. In Table 2 of the proposed rule, we summarized the estimated emission reductions from the contingency measures, and in Table 3 of the proposed rule, we presented the estimated emission reductions as percentages of OYW of RFP and OYW of progress both with and without trading emission reductions between direct PM_2.5 and NO_X.

In both of these tables in the proposed rule, we discounted the emission reductions from implementation of the Smog Check Contingency Measure by an amount calculated by CARB to reflect the effect of a decrease in Moyer Program funding in the San Joaquin Valley if the Smog Check Contingency Measure were triggered. However, in our final rule approving the Smog Check Contingency Measure SIP, we indicated that we agreed with comments challenging the discount that we had applied and concluded that the discount was inappropriate due to timing considerations. By no longer discounting the emission reductions attributed to the Smog Check Contingency Measure, the estimates for total emission reductions for implementation of all three contingency measures are slightly greater than had been presented in the proposed rule. The change in emissions estimates and percentages is minor and does not change any of the preliminary conclusions that we made in connection with our proposed action on the SJV PM_2.5 Contingency Measure SIP. Nonetheless, in the interest of presenting the most accurate information available, we are republishing Tables 2 and 3 to reflect the updated estimates of emission reductions from the Smog Check Contingency Measure.