Approval and Promulgation of Implementation Plans; California; San Joaquin Valley, Revisions to Motor Vehicle Emissions Budgets for Ozone
Key claim: EPA has approved California’s updated San Joaquin Valley motor vehicle emissions budgets for ozone-forming pollutants, which replace older budgets that regional transportation plans must stay within.
Abstract
(Rule · Environmental Protection Agency) The U.S. Environmental Protection Agency (EPA or “Agency”) is taking final action to approve a revision to the State of California’s state implementation plan (SIP) for the San Joaquin Valley (SJV) area. The revision includes an update to the SJV area’s motor vehicle emissions budgets (“budgets”) for nitrogen oxides (NOX) and volatile organic compounds (VOC) for the 2008 8- hour ozone national ambient air quality standards (NAAQS or “standards”). These updated budgets for 2026, 2029, and 2031 were developed with the latest modeling method approved for California. These updated budgets apply to all subareas within the SJV. Upon the effective date of this rule, the updated budgets will supersede the existing approved SJV subarea budgets for the 2008 ozone NAAQS that were based on an earlier emissions model. The EPA is approving the updated SJV ozone budgets in accordance with the requirements of the Clean Air Act (CAA or “Act”) and the EPA’s regulations.
Why this matters
Motor vehicle emissions budgets are the ceiling that regional transportation plans in ozone nonattainment areas must demonstrate conformity with, so updates directly shape which highway and transit projects can proceed in the San Joaquin Valley. Tightening or loosening these budgets affects both permitting timelines for transportation projects and the pace at which the region reduces ozone-forming NOx and VOC emissions.