The Environmental Protection Agency (EPA) is approving portions of the Alabama and South Carolina State Implementation Plan (SIP) submissions provided on August 20, 2018, and September 7, 2018, respectively, for inclusion into their respective SIPs. These approvals pertain to the infrastructure requirements of the Clean Air Act (CAA or Act) for the 2015 8-hour ozone national ambient air quality standard (NAAQS). Whenever EPA promulgates a new or revised NAAQS, the CAA requires that each state adopt and submit a SIP for the implementation, maintenance and enforcement of each NAAQS promulgated by EPA. Alabama and South Carolina certified that their SIPs contain provisions that ensure the 2015 8-hour ozone NAAQS is implemented, enforced, and maintained in their State. EPA has determined that Alabama and South Carolina infrastructure SIP submissions satisfy certain required infrastructure elements for the 2015 8-hour ozone NAAQS.