Air Quality Conformity
Established under the Clean Air Act (section 176), conformity plays an important role in helping states and tribal regions improve air quality in those areas that do not meet the National Ambient Air Quality Standards (NAAQS). Under the separate general and transportation conformity rules, federal agencies must work with State, Tribal and local governments in nonattainment and maintenance areas to ensure that federal actions, including highway and transit projects, conform to the initiatives established in the applicable state or tribal implementation plan.
On November 30, 1993, EPA promulgated a set of regulations, known as the General Conformity Regulations, which apply to non-transportation projects (i.e., projects not adding or expanding highways and transit). These regulations ensured that these types of federal actions also conformed to the SIPs (58 FR 63214) (PDF, 48 pp, 4.93MB).
The purpose of the General Conformity Rule is to:
- Ensure that federal activities do not interfere with the budgets in the state implementation plans (SIPs);
- Ensure the attainment and maintenance of the national ambient air quality standards (NAAQS); and
- Ensure that actions do not cause or contribute to new violations of a NAAQS
General conformity must be met for any federal action, defined as an activity engaged in by a department or agency of the federal government, or supported in any way by the federal government (including via financial assistance, licenses, permits, or approvals). The Federal Agency must make a determination that the activity conforms to the applicable State Implementation Plan before commencing the activity.
A conformity analysis must be conducted by the lead Federal Agency if a federal action would result in the generation of air emissions that would exceed conformity threshold levels of pollutants for which an air basin that is designated as a nonattainment or maintenance area under the NAAQS, or if emissions from the action are deemed regionally significant. A conformity analysis must demonstrate that the project emissions would conform, and thus would not degrade air quality in the impacted air basin. Conformity can be demonstrated via emission offsets, SIP provisions, or air quality modeling. The EPA is responsible for reviewing and approving SIPs, which are prepared and submitted to EPA by state environmental agencies.
EPA Region 3 contact: Brian Rehn (email@example.com) (215) 814-2176
Transportation conformity is a provision in the Clean Air Act (Section 176), which requires that a conformity demonstration be performed by either Federal Highway Administration (FHWA) or Federal Transit Administration (FTA) demonstrating that transportation-related highway construction will not interfere with achieving National Ambient Air Quality Standards.
- EPA's Transportation Conformity Webpage (PDF, 39 pp, 348KB)
- Status of Transportation Plans and TIPs in Region 3
- US EPA Transportation and Air Quality Contacts (PDF, 7 pp, 47KB)
- Regional EPA Transportation Conformity Contacts
- Transportation Conformity Reference Guide