The Environmental Protection Agency (EPA) is conditionally approving the visibility transport (prong 4) portions of revisions to the Tennessee State Implementation Plan (SIP), submitted by the Tennessee Department of Environment and Conservation (TDEC), addressing the Clean Air Act (CAA or Act) infrastructure SIP requirements for the 2010 1-hour Nitrogen Dioxide (NO<INF>2</INF>), 2010 1-hour Sulfur Dioxide (SO<INF>2</INF>), and 2012 annual Fine Particulate Matter (PM<INF>2.5</INF>) National Ambient Air Quality Standards (NAAQS). The CAA requires that each state adopt and submit a SIP for the implementation, maintenance, and enforcement of each NAAQS promulgated by EPA, commonly referred to as an "infrastructure SIP." Specifically, EPA is conditionally approving the prong 4 portions of Tennessee's March 13, 2014, 2010 1-hour NO<INF>2</INF> and 2010 1-hour SO<INF>2</INF> infrastructure SIP submission and December 16, 2015, 2012 annual PM<INF>2.5</INF> infrastructure SIP submission. All other applicable infrastructure requirements for these SIP submissions have been or will be addressed in separate rulemakings.