Air Plan Approval; Michigan; Redesignation of the Detroit, MI Area to Attainment of the 2015 Ozone Standards
Key claim: EPA proposes to redesignate the Detroit, Michigan area to attainment for the 2015 ozone NAAQS and to approve Michigan’s updated maintenance plan through 2040, including motor vehicle VOC and NOx emissions budgets for 2035 and 2040.
Abstract
(Proposed Rule · Environmental Protection Agency) The Environmental Protection Agency (EPA) is proposing to approve a request from the Michigan Department of Environment, Great Lakes, and Energy (EGLE) to redesignate the Detroit, Michigan area to attainment for the 2015 ozone National Ambient Air Quality Standards (NAAQS) because the request meets the statutory requirements for redesignation under the Clean Air Act (CAA). EGLE submitted this request on January 3, 2022, and submitted a supplement to this request on May 18, 2026. The EPA is also proposing to approve, as a revision to the Michigan State Implementation Plan (SIP), the State’s updated maintenance plan for the 2015 ozone NAAQS through 2040 in the Detroit area, including motor vehicle emissions budgets for 2035 and 2040, for both volatile organic compound (VOC) and oxides of nitrogen (NOX). The EPA is also initiating the adequacy process for these maintenance plan budgets. Additionally, the EPA is proposing to adjust the SIP submission and control measure implementation deadlines for certain Moderate requirements. Finally, the EPA is proposing to take final agency action on an exceptional events request submitted by EGLE on April 15, 2026, and concurred on by the EPA on June 4, 2026.
Why this matters
Redesignating Detroit to attainment for the 2015 ozone NAAQS lifts stricter nonattainment-area permitting burdens (such as more restrictive New Source Review) on Michigan sources while locking in transportation-conformity obligations tied to the 2035 and 2040 motor vehicle emissions budgets. It marks another Great Lakes urban area transitioning out of nonattainment status under the current standard, and the long maintenance horizon through 2040 shapes how Michigan and MPO planners must demonstrate conformity for future transportation projects.