In a letter dated June 7, 2018, the State of Florida, through the Florida Department of Environmental Protection (FDEP), submitted a request for the Environmental Protection Agency (EPA) to redesignate the Nassau County sulfur dioxide (SO<INF>2</INF>) nonattainment area (hereinafter referred to as the "Nassau County Area" or "Area") to attainment for the 2010 1-hour SO<INF>2</INF> primary national ambient air quality standard (NAAQS) and to approve an accompanying state implementation plan (SIP) revision containing a maintenance plan for the Area. The submittal was received by EPA on June 12, 2018. EPA is taking final action to determine that the Nassau County Area attained the 2010 1-hour SO<INF>2</INF> NAAQS by its applicable attainment date of October 4, 2018; to approve the SIP revision containing the State's plan for maintaining attainment of the 2010 1-hour SO<INF>2</INF> standard and to incorporate the maintenance plan into the SIP; and to redesignate the Nassau County Area to attainment for the 2010 1-hour SO<INF>2</INF> NAAQS.