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Air Quality

Transportation Conformity

Regulatory Activities

South Carolina is required to develop an air quality plan that demonstrates how the state will meet the health-based National Ambient Air Quality Standards (NAAQS) and incorporates the Transportation Conformity requirements for nonattainment areas.

The federal Clean Air Act (CAA) requires that air quality in every state meet these NAAQS. States that are designated as nonattainment areas by the EPA for Ozone (O3), carbon monoxide (CO), particulate matter (PM10 and PM2.5), or nitrogen dioxide (NO2) are required to revise their state implementation plan (SIP) to ensure that the standards are attained and maintained. Nonattainment areas are also required to implement transportation conformity for future projects. As part of this requirement, they must adopt interagency consultation procedures either by regulation or as a memorandum of agreement (MOA) between parties that is incorporated into the Transportation Conformity SIP.

South Carolina chose to develop and negotiate an MOA to formally incorporate the interagency consultation requirements for transportation conformity statewide.

Transportation Conformity Memorandum of Agreement

South Carolina opted to develop a Memorandum of Agreement (MOA) in place of regulations to ensure that interagency consultation procedures of transportation conformity are followed. The signatory parties to this MOA include:

  • S.C. DHEC
  • S.C. DOT
  • The Federal Highway Administration South Carolina Division Office
  • The Federal Transit Authority
  • EPA Region 4
  • A representative from each metropolitan planning organization within South Carolina.

The MOA applies to any nonattainment area in South Carolina for any applicable criteria pollutant. A copy of the current South Carolina Transportation Conformity MOA can be downloaded using the links below.

South Carolina Transportation Conformity Memorandum of Agreement (MOA)

Clarification Letter for Transportation Conformity Air Quality State Implementation Plan


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