The Environmental Protection Agency (EPA) is taking final action to approve portions of revisions to the North Carolina State Implementation Plan (SIP) submitted by the State of North Carolina through the North Carolina Department of Environmental Quality (formerly the North Carolina Department of Environment and Natural Resources), Division of Air Quality (DAQ), on October 14, 2004, March 24, 2006, and January 31, 2008. The revisions which EPA is approving are changes to the air curtain burner regulation of the North Carolina SIP. These revisions are part of North Carolina's strategy to meet and maintain the national ambient air quality standards (NAAQS). EPA has taken or will take action with respect to all other portions of these SIP revisions. This action is being taken pursuant to the Clean Air Act (CAA or Act) and its implementing regulations.