Determination of Attainment by the Attainment Date for the Kentucky Portion of the Louisville Moderate Area for the 2015 Ozone National Ambient Air Quality Standard

The Environmental Protection Agency (EPA) is proposing action related to the attainment date for the Kentucky portion of the Louisville, Kentucky-Indiana area (hereinafter referred to as the ‘‘Louisville, KY-IN Area’’ or ‘‘Area’’). The Kentucky portion of this Area is classified as ‘‘Moderate’’ nonattainment for the 2015 ozone National Ambient Air Quality Standard (NAAQS), and the Indiana portion of this Area has been redesignated to attainment for this NAAQS. EPA is proposing to determine, with the consideration of exceptional events, that the Kentucky portion of the Louisville, KY-IN Area attained the standard by the applicable August 3, 2024, attainment date. This action, if finalized, will fulfill EPA’s statutory obligation to determine whether the Kentucky portion of the Louisville, KY-IN Area attained the 2015 8-hour ozone NAAQS by the Moderate attainment date. As part of this rulemaking, EPA also proposes to take final agency action on the portion of an exceptional events request submitted by the Louisville Metro Air Pollution Control District (LMAPCD) on June 11, 2025, addressing six days in June 2023. EPA concurred on these six days on August 12, 2025. The proposed determination by the attainment date is based on EPA’s partial concurrence on the exceptional events demonstration. This action is being taken under the Clean Air Act (CAA or Act).