Approval and Promulgation of Implementation Plans; North Carolina: Non-Interference Demonstration for Removal of Federal Low-Reid Vapor Pressure Requirement for the Greensboro/Winston-Salem/High Point Area

The Environmental Protection Agency (EPA) is approving the State of North Carolina's April 12, 2013, State Implementation Plan (SIP) revision to its approved maintenance plan for the Greensboro/ Winston-Salem/High Point 1997 8-hour Ozone Maintenance Area (Triad). Specifically, North Carolina's SIP revision, including updated modeling, shows that the Triad Area would continue to maintain the 1997 8-hour ozone standard if the currently applicable Federal Reid Vapor Pressure (RVP) standard for gasoline of 7.8 pounds per square inch (psi) were modified to 9.0 psi for four portions (Davidson, Forsyth, Guilford and Davie Counties) of the "Triad Area" during the high- ozone season. The State has included a technical demonstration with the SIP revision to demonstrate that a less-stringent RVP standard of 9.0 psi in these portions of this area would not interfere with continued maintenance of the 1997 8-hour ozone national ambient air quality standards (NAAQS) or any other applicable standard. Approval of this SIP revision is a prerequisite for EPA's consideration of an amendment to the regulations to remove the aforementioned portions of the Triad Area from the list of areas that are currently subject to the Federal 7.8 psi RVP requirements. In addition, the revised on-road mobile and non-road mobile source emissions modeling associated with the requested modification to the RVP standard utilizes the updated Motor Vehicle Emissions Simulator (MOVES) and NONROAD2008 models which are the most current versions of modeling systems available for these sources. EPA has determined that North Carolina's April 12, 2013, SIP revision with respect to the revisions to the modeling and associated technical demonstration associated with the State's request for the removal of the Federal 7.8 psi RVP requirements, and with respect to the updated on-road mobile, non-road mobile and area source emissions, is consistent with the applicable provisions of the Clean Air Act (CAA or Act). Should