Pursuant to Clean Air Act Section 176(c) (42 U.S.C. 7506) and the U.S. Environmental Protection Agency’s implementing regulations (40 CFR Part 93, Subpart B and 40 CFR Part 51, Subpart W), general conformity is required for NAAQS nonattainment and maintenance areas. The intent of general conformity is to prevent the air quality impacts of a proposed federal action, under Title 23 U.S.C., from causing or contributing to new violations of the air quality standards, exacerbating existing violations, or interfering with the purpose of the applicable implementation plan.
Federal agencies must perofrm a conformity evaulation and make a determination that a federal action conforms to an applicable implementation plan. The federal agency works with State, Tribal, and local agencies and governments when designing a project that affects nonattainment and maintenance areas so that emissions conform to the purpose of the air quality plans in an applicable implementation plan.
In order to streamline a conformity evaluation process, SIP set-aside accounts were established in the 2012 AQMP and revised in the 2016 AQMP. The revised set-aside account to accommodate projects subject to general conformity included a balance of: 2.0 tpd of NOx and 0.5 tpd of VOC each year from 2017 to 2030, and 0.5 tpd of NOx and 0.2 tpd of VOC in 2031. Emissions from general conformity projects are tracked by the South Coast AQMD tracking system and debited from the account on a first-come-first-serve basis. Below is a list of general conformity projects approved by South Coast AQMD that rely on the SIP-set aside account to demonstrate conformity:
Federal agencies can also mitigate and offset emissions to conform, instead of relying on the SIP set-aside account or if the SIP set-aside account cannot accommodate emissions from the federal action. These options require agreements to apply mitigation measures or plans for obtaining offsets, and must be in place before a federal agency can rely on them to demonstrate conformity. Below are agreements between South Coast AQMD and federal agencies for general conformity projects: