Air Plan Approval; North Carolina; Charlotte-Rock Hill Area Maintenance Plan for the 2008 8-Hour Ozone NAAQS
Key claim: EPA proposes to approve North Carolina’s plan to keep the Charlotte area meeting the 2008 ozone air standard through 2035, including vehicle-emission budgets for nitrogen oxides and volatile organic compounds.
Abstract
(Proposed Rule · Environmental Protection Agency) On February 28, 2025, the State of North Carolina, through the North Carolina Department of Environmental Quality, Division of Air Quality (NCDAQ), submitted a request for the U.S. Environmental Protection Agency (EPA) to approve a State Implementation Plan (SIP) revision containing the State’s plan for maintaining the 2008 ozone National Ambient Air Quality Standard (NAAQS) through 2035 for the North Carolina portion of the bi-state Charlotte-Rock Hill, North Carolina-South Carolina 2008 8-hour ozone nonattainment area (the entire area is hereinafter referred to as the “bi-state Charlotte Area” and the North Carolina portion is hereinafter referred to as the “Charlotte Area”). The EPA is proposing to approve and incorporate North Carolina’s second 10-year maintenance plan to maintain attainment of the 2008 8-hour ozone NAAQS in the bi-state Charlotte Area, including the 2018 and 2035 motor vehicle emission budgets (budgets) for nitrogen oxides (NOX) and volatile organic compounds (VOC) for the Charlotte Area, into the SIP. The EPA is also notifying the public of the status of the EPA’s adequacy determination for the sub-area budgets for the Charlotte Area.
Why this matters
Second 10-year maintenance plans lock in federally enforceable emissions budgets that constrain state and metro transportation planning long after an area is redesignated to attainment. For the Charlotte-Rock Hill region, EPA’s proposed approval means highway and transit projects must demonstrate conformity with the NOx and VOC budgets through 2035, keeping ozone-related permitting pressure on the vehicle sector even as stationary-source nonattainment burdens ease.