Daily Rules, Proposed Rules, and Notices of the Federal Government
Readers should note that only comments about the new modeling data discussed in this document and related issues will be considered during the comment period. Issues related to the August 19, 2009 proposed rule that are not directly affected by the data referenced in this Notice of Data Availability are not open for further comment.
Throughout this document, the terms “we”, “us”, and “our” refer to EPA.
On August 19, 2009 (74 FR 41818), EPA proposed to approve state implementation plan (SIP) revisions submitted by the California Air Resources Board (CARB) on June 5, 2009 relating to the State's basic and enhanced vehicle I/M program (“2009 I/M Revision”) contingent upon California's submittal of revisions to the enhanced program performance standard evaluations to address a different attainment year for the Western Mojave Desert 8-hour ozone nonattainment area and to address California's base-year program performance.
As explained in the August 19, 2009 proposal, these revisions to California's enhanced program performance standard evaluation were necessary for two reasons. First, the submitted performance modeling evaluation for the Western Mojave Desert 8-hour ozone nonattainment area was based on the State's choice of 2020 as the horizon year, based on the attainment deadline for 8-hour ozone nonattainment areas classified as “severe-17.”
Second, CARB did not provide base year modeling evaluations for the six areas in the State that are subject to the enhanced I/M requirements in 40 CFR part 51, subpart S. The six areas are the South Coast Air Basin, San Joaquin Valley, Western Mojave Desert, Sacramento Metro, Coachella Valley, and Ventura County. We noted that a base year modeling run is required to allow for a more definitive conclusion that the California enhanced I/M program obtained the same or lower emission levels as the EPA model program by January 1, 2002, and that the program will maintain this level of emission reduction (or better) through the applicable 8-hour ozone attainment deadlines, as required by 40 CFR 51.351(f). Based on our preliminary modeling analyses and evaluation of the data provided in CARB's submittal, however, we noted that we expect these revised modeling evaluations will satisfy the regulatory requirements. 74 FR 41818-41823. In our proposed rule, we indicated that we would notify the public of any additional information that is provided to address these issues. Publication of this NODA is intended to serve this purpose.
On October 28, 2009, CARB submitted the revised enhanced I/M performance modeling analyses described above. We placed the analyses in the docket on October 29, 2009. Specifically, CARB submitted (1) revised enhanced program performance standard evaluations for the Western Mojave Desert area based on a horizon year of 2018, and (2) 2002 base year performance modeling evaluations for the six areas in the State that are subject to the enhanced I/M requirements in 40 CFR part 51, subpart S (the South Coast Air Basin, San Joaquin Valley, Western Mojave Desert, Sacramento Metro, Coachella Valley, and Ventura County). We find that selection of year 2018 by California as the “year before the attainment year” for Western Mojave Desert for enhanced performance modeling purposes is acceptable on the presumption that CARB will amend its voluntary reclassification request from “severe-17” to “severe-15.” We interpret section 181(b)(3) to allow for voluntary reclassification by a state to the latter, but not the former.
We have also reviewed the submitted modeling data and find that the inputs to the MOBILE6.2 model accurately reflect the California I/M program. Based on the modeling results for Western Mojave Desert submitted on October 28, 2009, together with the performance standard modeling results contained in the 2009 I/M Revision, we believe that California has now demonstrated that the California I/M program would achieve greater percent emissions reductions (relative to the no I/M scenario) for VOC and NO
Moreover, the modeling results for the California I/M program in 2002 show that the California program achieved greater percent emissions reductions (relative to the no I/M scenario) for VOC and NO