Air Plan Approval; Kentucky; Louisville Area Limited Maintenance Plan for the 1997 8-Hour Ozone NAAQS
Key claim: EPA is making Kentucky’s plan to keep ozone pollution in the Louisville area within the 1997 eight-hour federal standard legally binding as part of the state air plan through the second 10-year maintenance period.
Abstract
(Rule · Environmental Protection Agency) The U.S. Environmental Protection Agency (EPA or Agency) is approving a State Implementation Plan (SIP) revision submitted by the Commonwealth of Kentucky through the Energy and Environment Cabinet (Cabinet) on behalf of the Louisville Metro Air Pollution Control District (District) via a letter dated June 3, 2024. The SIP revision consists of a Limited Maintenance Plan (LMP) for the Kentucky portion of the bi-state Louisville, Kentucky-Indiana 1997 8-hour ozone maintenance area (the “bi-state Louisville Area”). The Kentucky portion of the bi-state Louisville Area is comprised of Bullitt, Jefferson, and Oldham Counties in Kentucky (the “Louisville Area”). The EPA is approving the Louisville Area’s LMP because it provides for the maintenance of the 1997 8-hour ozone National Ambient Air Quality Standards (NAAQS) within the bi-state Louisville Area through the end of the second 10-year portion of the maintenance period. The effect of this action is to make certain commitments related to maintenance of the 1997 8-hour ozone NAAQS in the Louisville Area federally enforceable as part of the Kentucky SIP.
Why this matters
Limited maintenance plans lock in a state’s ozone-control commitments as federal law for former nonattainment areas, preserving federal enforceability even after an area has long shown clean air. For Louisville, this closes out the second 10-year maintenance period for the superseded 1997 ozone standard, keeping transportation conformity and backstop obligations in place while the area continues meeting tighter current standards.