The Environmental Protection Agency (EPA) is taking final action to approve revisions to the Kentucky State Implementation Plan (SIP), submitted by the Commonwealth of Kentucky, through the Kentucky Division for Air Quality (KDAQ), on March 21, 2011, October 29, 2013, October 28, 2016, and March 24, 2017. The revisions were submitted by KDAQ on behalf of the Louisville Metro Air Pollution Control District, which has jurisdiction over Jefferson County, Kentucky. The revisions include changes to Jefferson County Regulations regarding Reasonably Available Control Technology (RACT) for two major sources of nitrogen oxides (NOx) and the removal of a volatile organic compounds (VOC) bubble rule.