Final rule · 2026-03880

Air Plan Approval; Michigan; Moderate Attainment Plan Elements for the Allegan County, Berrien County, and Muskegon County Areas for the 2015 Ozone Standard

The Environmental Protection Agency (EPA) is approving a revision to the Michigan State Implementation Plan (SIP) as meeting the reasonable further progress (RFP) requirements of the Clean Air Act (CAA) for the Allegan County (partial county), Berrien County, and Muskegon County (partial county) Moderate nonattainment areas for the 2015 ozone national ambient air quality standard (NAAQS). The EPA is also approving updated 2017 base year emissions inventories and is finding adequate and approving the 2023 motor vehicle emissions budgets (budgets) associated with the Allegan County, Berrien County, and Muskegon County Moderate ozone nonattainment RFP demonstrations. The EPA is approving these portions of the State's SIP submission pursuant to section 110 and part D of the CAA, and EPA's regulations. The EPA proposed to approve this action on December 11, 2025, and received no adverse comments.