Air Plan Approval; Michigan; Clean Data Determination for the Detroit Area for the 2015 Ozone Standard

The Environmental Protection Agency (EPA) is determining under the Clean Air Act (CAA) that the Detroit, Michigan nonattainment area (hereafter also referred to, respectively, as the "Detroit area" or "area") has attained the 2015 ozone National Ambient Air Quality Standards (NAAQS or standard). This determination is based upon complete, quality-assured, and certified ambient air monitoring data for the 2020-2022 design period showing that the area achieved attainment of the 2015 ozone NAAQS, based on the exclusion of certain exceedances of the 2015 ozone NAAQS that were due to exceptional events. EPA is taking final agency action on an exceptional events request submitted by the Michigan Department of Environment, Great Lakes, and Energy (EGLE) on January 26, 2023. As a result of the clean data determination, based on exclusion of event-influenced data, EPA is suspending the requirements for the area to submit attainment demonstrations and associated Reasonably Available Control Measures (RACM), Reasonable Further Progress (RFP) plans, contingency measures for failure to attain or make reasonable progress, and other planning SIPs related to attainment of the 2015 ozone NAAQS, for as long as the area continues to attain the 2015 ozone NAAQS. This action does not constitute a redesignation of the area to attainment of the 2015 ozone NAAQS.