Regional Air Quality Planning Program

Overview

SCAG’s Air Quality Planning Program coordinates with various air quality and transportation stakeholders in Southern California to ensure compliance with the federal, state, and regional air quality planning requirements. The federal Clean Air Act Section 176© (42 U.S.C. 7401 to 7671q) requires transportation conformity to ensure that federal funding and approval are given to highway and transit projects consistent with (i.e., “conform to”) the air quality goals established by an applicable air quality management plan (AQMP) or a state implementation plan. Conformity, for the state implementation plan, means that federally supported transportation activities will not cause or contribute to new violations of federal air quality standards, worsen existing violations, or delay timely attainment of the applicable national ambient air quality standards.​ 

As the federally designated metropolitan planning organization for the six-county Southern California region, SCAG is required by law to be responsible for the transportation conformity determination on the Regional Transportation Plan/Sustainable Communities Strategy, the Federal Transportation Improvement Program, and their amendments. SCAG is also responsible for preparing the regional transportation strategy and transportation control measures portion of AQMP for the South Coast Air Basin. In addition, SCAG provides the socio-economic growth forecast and transportation activity projections to all the air districts in the SCAG region.  

Air Quality Plans 

Air Quality Management Plans and State Implementation Plans (SIPs) 

The SCAG region contains four air basins and five air districts. The South Coast Air Basin is within the jurisdiction of the South Coast Air Quality Management District. The Ventura County portion of the South Central Coast Air Basin is within the jurisdiction of the Ventura County Air Pollution Control District. The Mojave Desert Air Basin is under the jurisdiction of three air districts: the Mojave Desert Air Quality Management District, the South Coast Air Quality Management District, and the Antelope Valley Air Quality Management District. The Salton Sea Air Basin is under the jurisdiction of the Imperial County Air Pollution Control District and the South Coast Air Quality Management District.  

Areas in California designated as “Maintenance” or “Nonattainment” for one or more national primary ambient air quality standards are required under the federal Clean Air Act to develop plans meeting specific air quality planning requirements depending on the classification based on severity. Air quality plans and corresponding documents are maintained and available on the California Air Resources Board website.