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Air Quality

Regulation and SIP Management

Redesignation Demonstration and Maintenance Plan for the York County Portion of the Charlotte-Gastonia-Rock Hill NC-SC Nonattainment Area

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On July 18, 1997, the United States Environmental Protection Agency (EPA) promulgated amendments to the National Ambient Air Quality Standards (NAAQS) for ozone. Based on its review of available scientific evidence linking exposures to ambient ozone to adverse health and welfare effects at levels allowed by the 1-hour ozone standards, the EPA replaced the 1-hour primary standard with an 8-hour standard at a level of 0.08 ppm based on the 3-year average of the annual fourth-highest daily maximum 8-hour average ozone concentrations measured at each monitor within an area. The 1-hour secondary standard was also replaced by an 8-hour secondary standard identical to the primary standard. On April 30, 2004, the EPA designated and classified a portion of York County, South Carolina within the Rock Hill Fort Mill Area Transportation Study (RFATS) Metropolitan Planning Organization (MPO) as a moderate nonattainment area for the 8-hour ozone NAAQS as part of the Charlotte-Gastonia-Rock Hill NC-SC Nonattainment Area. Information on the RFATS State Implementation Plan (SIP) attainment demonstration submitted to the EPA can be found here.

Air quality monitoring data from 2008 to 2010 indicates that the York County portion of the Charlotte-Gastonia-Rock Hill NC-SC Nonattainment Area currently meets the 1997 8-hour ozone NAAQS of 0.08 ppm. As such, the Department has submitted a SIP revision which requests that the EPA redesignate the York County portion of the Charlotte-Gastonia-Rock Hill NC-SC Nonattainment Area to attainment for the 1997 8-hour ozone NAAQS. This revision also provided a maintenance plan which fulfills the requirements of Section 175A of the Clean Air Act as amended, that will ensure the area remains in attainment of the 1997 8-hour ozone NAAQS through 2022.

DHEC published a Notice of Intent to Revise the SIP which included an announcement of a 30-day comment period and opportunity to request a public hearing in the State Register on March 25, 2011. A prehearing package was submitted to the EPA on April 1, 2011. No request for a public hearing was received, and the public comment period closed on April 25, 2011. Written comments were received from the EPA and are addressed in the final SIP package.

On December 26, 2012, EPA published a final approval (77 FR 75862) of the redesignation plan for the South Carolina portion of the Charlotte-Gastonia-Rock Hill NC-SC (Metrolina) nonattainment area. This redesignated the area from nonattainment to attainment. EPA also approved South Carolina's 1997 8-hour ozone NAAQS maintenance plan, including the associated motor-vehicle emissions budget (MVEB), into the South Carolina State Implementation Plan (SIP).

For questions regarding this SIP revision, please contact:

Andrew O. Hollis
Division of Air Assessment, Innovations, and Regulation
Bureau of Air Quality
2600 Bull Street; Columbia, SC 29201

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For more information please contact the Bureau of Air Quality at (803) 898-4123 or by email.