Delaware Valley Regional Planning Commission

Air Quality Conformity

The Federal Clean Air Act and the transportation planning provisions of Title 23 and Title 49 of the United States Code are intended to ensure that integrated transportation and air quality planning occurs in the areas that do not or previously have not met the National Ambient Air Quality Standards (NAAQS). These areas, known as nonattainment or maintenance areas respectively, require a process to demonstrate that transportation projects included in the region’s Long-Range Plan (Plan) or Transportation Improvement Program (TIP) will not impede a region’s progress toward meeting or maintaining the federal air quality standards.

Transportation conformity is the federally mandated analytical process through which Metropolitan Planning Organizations (MPOs) demonstrate that the transportation investments, strategies, and programs included in the Plan and TIPs are consistent with air quality goals established in State Implementation Plans (SIP) for achieving the National Ambient Air Quality Standards (NAAQS). Conformity demonstrations show that emissions from projects in transportation plans and programs do not exceed the SIP targets ("budgets") for emissions from mobile sources.

The nine-county DVRPC planning area is part of the:

  • Philadelphia-Wilmington-Atlantic City Ozone Nonattainment Area
  • Philadelphia-Wilmington, PA-NJ-DE PM2.5 Maintenance Area
  • New York - Northern New Jersey - Long Island, NY-NJ-CT PM2.5 Maintenance Area
  • Delaware County PM2.5 Maintenance Area

Adopted Conformity Documents

The DVRPC Board adopted the transportation conformity findings in July 2026. This document demonstrates transportation conformity for: 

DVRPC procedures for developing a Transportation Conformity Determination are detailed in each conformity report. Further information on these procedures is available here:

For more information on transportation conformity, visit the FHWA or EPA webpages.