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 that are consistent with (“conform to”) the air quality goals established by an applicable air quality management plan (AQMP) or a state implementation plan (SIP). Conformity, to the purpose of the SIP, means that federally supported transportation activities will not cause or contribute to new violations of the federal air quality standards, worsen existing violations, or delay timely attainment of the applicable national ambient air quality standards (NAAQS).​

As the federally-designated Metropolitan Planning Organization (MPO) 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 (RTP/SCS), the Federal Transportation Improvement Program (FTIP), and their amendments. SCAG is also responsible for preparing the regional transportation strategy and transportation control measures (TCMs) 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. 

Resources & Links

U.S. Environmental Protection Agency

• Transportation Conformity
  Information on U.S. Environmental Protection Agency’s (EPA) transportation conformity program.
• State Implementation Plan Status Reports
  Reports on the current status of air quality State Implementation Plan (SIP) submittals and EPA’s actions.
• Office of Transportation and Air Quality
  Learn more about EPA’s Office of Transportation and Air Quality programs that address emissions from a range of mobile sources.
• Climate Change
  Find out more information about climate change, impacts, what EPA is doing, and what you can do.
• Clean Air Excellence Awards
  Recognizes and honors outstanding innovative efforts to help make progress in achieving cleaner air.
• Air Toxics Website
  Information and details on air toxics from the U.S. Environmental Protection Agency
• Air Actions, Region 9
  List of most recent air actions implemented or passed in the SCAG region.

U.S. Department of Transportation

• Federal Highway Administration, Transportation Conformity
  Ensures Federal funding and approval for transportation activities are consistent with air quality goals in nonattainment and maintenance areas.
• Federal Highway Administration, MAP-21
  The Moving Ahead for Progress in the 21st Century Act (MAP-21) provides funding for surface transportation programs in 2013 and 2014.
• Federal Highway Administration, SAFETEA-LU
  The Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (SAFETEA-LU) guaranteed public transportation funding totaling $244.1 billion and marked the largest surface transportation investment in the Nation’s history.
• Federal Transit Administration
  Direct website to the Federal Transit Administration.

California Air Resources Board

• ARB Formal Rulemaking Activity
  Presented is a list of the Air Resources Board (ARB) rulemaking activity; ARB is responsible for conducting rulemakings to adopt and amend regulations covering a variety of areas.
• Air Quality and Land Use Handbook: A Community Health Perspective (March 2005)
  The handbook intended to serve as a general reference guide for evaluating and reducing air pollution impacts associated with new projects that go through the land use decision-making process.
• CARB 2020 Mobile Source Strategy
  CARB staff is developing the 2020 Mobile Source Strategy to take an integrated planning approach to identify the level of transition to cleaner mobile source technologies needed to achieve all of California’s targets.
• EMFAC202Y Updates
  July 30, 2020
• EMFAC2021  
  (US EPA Approved) 
• EMFAC2017
  (US EPA Approved)
• EMFAC2014
  (US EPA Approved)
• School Health, The Children’s School Bus Exposure Study
  Informs communities about children’s exposure to pollutants during school bus commuting and simple steps to reduce exposure.
• Strategies to Reduce Air Pollution Exposure Near High-Volume Roadways: Technical Advisory
  This Technical Advisory was released in April 2017 as a supplement to ARB’s Air Quality and Land Use Handbook: A Community Health Perspective. It is intended to provide planners and other stakeholders involved in land use planning and decision-making with information on scientifically based strategies to reduce exposure to traffic emissions near high-volume roadways in order to protect public health and promote equity and environmental justice.

California Department of Transportation

• Air Quality Analysis and Coordination
  The Caltrans Headquarters Air Quality Branches manage Department air quality analysis and Transportation Conformity policy, assist Caltrans District Office Environmental and Planning staff with regional and project-level air quality issues, consult and coordinate with State, Federal, and regional air and transportation planning agencies, build and maintain air quality analysis tools and guidance, and manage research studies related to transportation air quality issues.

Air Quality Districts

• Antelope Valley Air Quality Management District
  Direct link to the Antelope Valley Air Quality Management District webpage.
• Imperial County Air Pollution Control District
  Direct link to the Imperial County Air Pollution District webpage.
• Mojave Desert Air Quality Management District
  Direct link to the Mojave Desert Air Quality Management District webpage.
• South Coast Air Quality Management District (SCAQMD)
  Direct link to the South Coast Air Quality Management District webpage.
  • SCAQMD, Air Quality Management Plans
    ​SCAQMD is responsible for preparing an overall plan (AQMP) update to meet federal requirements and/or incorporate the latest planning information concerning its air district region.
  • SCAQMD Guidance Document for Addressing Air Quality Issues in General Plans and Local Planning (May 2005)
• Ventura County Air Pollution Control District
  Direct link to the Ventura County Air Pollution Control District webpage.

Universities and Research Centers

• UCLA Center for Occupational & Environmental Health
  Air Pollution Helping to assess exposure and understand the health effects of air pollution in Southern California.
• Southern California Particle Center
  Investigating the underlying mechanisms that produce the health effects associated with exposure to particulate matter.

Non-Governmental Organizations

• Surface Transportation Policy Partnership
  Surface Transportation Policy Partnership (STPP) is a diverse, nationwide coalition working to ensure safer communities and smarter transportation choices that enhance the economy, improve public health, promote social equity, and protect the environment.
• Coalition for Clean Air
  Coalition for Clean Air is dedicated to restoring clean, healthy air to California by advocating for effective public policy and practical business solutions.
• Environmental Defense Fund
  Guided by science and economics, the Environmental Defense Fund aims to find solutions to the most serious environmental problems.
• American Lung Association, State of the Air
  The American Lung Association aims to protect people from air pollution impacts that lead to lung disease and other related harmful effects.

Air Quality Plans 

Air Quality Management Plans (AQMPs) / 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: 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 Bain is under the jurisdiction of the Imperial County Air Pollution Control District and the South Coast Air Quality Management District.  

Areas in California that are designated as 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 (CARB) website.