Transportation conformity is the process by which Metropolitan Planning Organizations (MPO) or Departments of Transportation demonstrate that transportation projects included in a region's Long-Range Plan (Plan) or Transportation Improvement Programs (TIP) do not cause new air quality violations, worsen existing violations, or delay timely attainment of the National Ambient Air Quality Standards (NAAQS). Transportation conformity is a requirement of the Clean Air Act (CAA) in areas that do not meet the NAAQS or have previously been in violation of the NAAQS. Areas currently not meeting the NAAQS are known as nonattainment areas and areas that previously have not attained the NAAQS are known as maintenance areas.
A transportation conformity demonstration shows that the region's TIPs and Plan are following or "conforming to" the State Implementation Plan (SIP) to meet the NAAQS. In nonattainment areas that do not have federally approved SIPs, the current conformity guidance, known as the Final Rule, issued by the United States Environmental Protection Agency (US EPA) establishes guidelines for conducting transportation conformity demonstrations.
The Delaware Valley Regional Planning Commission (DVRPC) region is in nonattainment for two of the NAAQS (ozone and PM2.5). Portions of the region are maintenance areas for a third NAAQS (carbon monoxide or CO).
Since ozone is not directly emitted, but is formed by the combination of volatile organic compounds (VOC) and nitrogen oxides (NOx) in the presence of sunlight, conformity is demonstrated by analysis of the component pollutants. PM2.5 is directly emitted and precursor pollutants--in this case NOx--are also analyzed to demonstrate transportation conformity. This Executive Summary highlights DVRPC's conformity demonstration for:
Volatile Organic Compounds (VOCs) and Nitrogen Oxides (NOx) meeting the eight hour ozone NAAQS requirements in:
- the DVRPC portion of the Philadelphia-Wilmington-Atlantic City Ozone Nonattainment Area;
Direct Fine Particulate Matter (PM2.5) and Precursor NOx meeting the PM2.5 NAAQS requirements in:
- the DVRPC portion of the Philadelphia-Wilmington, PA-NJ-DE Annual PM2.5 Nonattainment Area; and
- the DVRPC portion of the Philadelphia-Wilmington, PA-NJ-DE 24-hour PM2.5 Nonattainment Area; and E-2 Transportation Conformity Demonstration
- the DVRPC portion of the New York-Northern New Jersey-Long Island, NY-NJ-CT Annual PM2.5 Nonattainment Area; and
- the DVRPC portion of the New York-Northern New Jersey-Long Island, NY-NJ-CT 24- hour PM2.5 Nonattainment Area.
Carbon Monoxide (CO) meeting the CO NAAQS requirements in:
- the Philadelphia-Camden CO Maintenance Area;
- the City of Burlington in Burlington County, New Jersey CO Maintenance Area;
- the City of Trenton in Mercer County, New Jersey CO Maintenance Area.
This summary serves as an inclusive document that demonstrates the transportation conformity of the DVRPC TIPs and Long-Range Plan with all applicable SIPs and NAAQS requirements for the above pollutants within the noted areas.