California Air Resources Board

Recent and historical State Implementation Plan (SIP) activities for 8-hour ozone, PM2.5, PM10, and lead in the South Coast Air Basin and the Coachella Valley. 

• 2024 South Coast PM2.5 Plan
• 2022 Air Quality Management Plan for the 70 parts per billion 8-hour Ozone Standard in the South Coast Air Basin and Coachella Valley
• 2022 Coachella Valley 75 ppb 8-Hour Ozone Reasonable Further Progress SIP
• 2021 South Coast PM2.5 Redesignation Request and Maintenance Plan
• 2021 South Coast PM10 Maintenance Plan
• 2020 South Coast PM2.5 SIP Revision
• 2020 Coachella Valley Extreme 8-Hour Ozone Plan
• 2019 South Coast 8-Hour Ozone SIP Update
• 2019 South Coast PM_2.5 Contingency Measure
• 2018 South Coast SIP Revisions and Updates
• 2016 Ozone and PM_2.5 for the South Coast Air Basin and Coachella Valley
• 2016 South Coast AQMP Reasonably Available Control Technology SIP Demonstration
• 2015 Minor Revision to the South Coast 2012 PM_2.5 Plan
• 2014 Updates to the 1997 8-Hour Ozone Standard SIPs: Coachella Valley and Western Mojave Desert 8-Hour Ozone Nonattainment Areas
• 2012 South Coast Ozone and PM_2.5 Plans
• 2012 Lead SIP for Los Angeles County
• 2011 8-Hour Ozone and PM_2.5 Revisions
• 2011 PM_2.5 Progress Report
• 2010 South Coast Air Basin PM10 Maintenance Plan
• 2010 Coachella Valley PM10 Maintenance Plan 
• 2008 Ozone Early Progress Plans
• 2007 South Coast and Coachella Valley 8-Hour Ozone and PM_2.5 Plan
• 2005 Carbon Monoxide Plan
• 2003 1-Hour Ozone and PM10 Plan

What is residential waste burning?

Residential waste burning, for the purposes of this Air Toxic Control Measure (ATCM), is defined as the outdoor burning of waste, other than natural vegetation, generated by one- or two-family residences. 

Individual local air district rules address the types of residential waste that are allowed to be burned. Typically, these materials could include garbage, paper, cloth, and wood wastes burned in 55-gallon drums referred to as burn barrels. Local air district rules vary throughout the State. Prior to 2003, nine of the local air districts restricted outdoor burning at residences to natural vegetation only, and then, only under certain conditions. The remaining air districts allowed residential waste burning of materials other than natural vegetation. Six air districts allowed the burning of all types of materials, including household garbage, in all or part of the air district. The remaining air districts did not allow the burning of household garbage but allowed the burning of other materials such as paper, cardboard, cloth, and wood products in all or part of the air district. About 2.2 million people lived in areas where air districts allowed some form of residential waste burning.

Why is CARB focusing on residential waste burning?

The U.S. EPA has identified residential waste burning as a major source of polychlorinated dibenzo-p-dioxins and dibenzofurans (collectively referred to as dioxins). Dioxins in particular are the most potent carcinogens identified to date by the ARB as toxic air contaminants. In addition to dioxins, many other toxic air contaminants are generated from residential waste burning, including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), benzene, and 1,3-butadiene. 

These toxic air contaminants may result in substantial health impacts, ranging from headaches, dizziness, rapid heartbeat, and liver and kidney damage to cancer. Other air pollutants found in smoke produced from residential waste burning include carbon dioxide, oxides of nitrogen, and particulate matter. Most of the particulate matter emitted from residential waste burning is small enough to be inhaled and can be especially harmful to people with existing respiratory illness, the aged, and the very young. Exposure to such particles may worsen existing disease conditions and can produce symptoms ranging from breathing difficulties to increased respiratory infection and even death.

At a meeting on June 28, 2001, the Board directed staff to develop an ATCM for residential waste burning, after several local air districts asked CARB to take the lead with a statewide measure. At a public hearing on February 21, 2002, the Board approved an Airborne Toxic Control Measure to Reduce Emissions of Toxic Air Contaminants from Outdoor Residential Waste Burning. Restricting the outdoor burning of non-vegetation waste to very low population density areas will decrease the overall emissions statewide and lessen the adverse impacts to community health from household waste burning, especially in densely populated incorporated places.

What does the ATCM do?

The ATCM is a statewide control measure to reduce air toxic emissions and protect community health. Provisions that took effect on January 1, 2004, include:

• Eliminating outdoor residential burning of all household waste except vegetation;
• Eliminating the use of burn barrels because they facilitate the illegal burning of waste materials;
• Requiring all residential burning to take place on a day authorized for burning by an air district; and
• Providing exemptions in areas with very low population density that lack alternatives for waste disposal.

The temporary exemption areas referenced above were approved by air district Governing Boards and confirmed by CARB in 2003. Exemption area designations are reevaluated every ten years.

What are the exemptions and how will they be applied?

Only one- and two-family residences in the specifically identified and approved exemption areas can utilize the exemptions. There are only two potential exemptions:

1. Permission to burn dry, non-glossy paper and cardboard, and/or
2. Limited use of a burn barrel or backyard incinerator.

The ATCM requires exemption areas be limited to very rural areas throughout the State as determined by population density. CARB used data from the most recent U.S. decennial census (2000) to determine population density, or persons per square mile, in census zip code tabulation areas. No exemptions are allowed in incorporated places or areas where the population density is greater than 10 persons per square mile. The exemption areas follow easily recognizable boundaries, such as zip codes, and can be further refined by air districts using a suitable mapping unit, such as census blocks. 

Burn barrels may continue to be used in any jurisdiction where a local ordinance or other enforceable mechanism requiring their use is already in effect as of January 1, 2002, unless it is subsequently rescinded or revoked. Conversely, an air district may not seek an exemption for the use of burn barrels in any jurisdiction that bans their use through air district rules, local ordinances, or other enforceable mechanisms in effect on January 1, 2002, or thereafter. Air districts may not request exemptions for the burning of paper and cardboard if it is already prohibited under air district rules in effect as of January 1, 2002, nor request an exemption for any jurisdiction where a local ordinance or other enforceable mechanism is already in effect prohibiting these materials.

Air districts do not have to request exemption areas and many of them implemented the statewide ATCM by prohibiting burn barrels and incinerators and allowing only vegetation burning in piles on the ground at residences. A few air districts already prohibited some or all of these activities in heavily populated areas.

What authority does CARB have to regulate residential waste burning?

In 1983, the California Legislature established a two-step process (AB 1807) of risk identification and risk management to address the potential health effects from airborne toxic substances and to reduce their risks. 

1. CARB and Office of Environmental Health Hazard Assessment (OEHHA) determine if a substance meets the definition of a toxic air contaminant, and to what extent. 
2. If a substance is determined to be a toxic air contaminant, CARB begins the process of risk management.  In this step, the CARB evaluates the need, feasibility, and cost of reducing emissions of a particular substance. 

CARB identified benzene as a toxic air contaminant in 1984. Dioxins were identified as toxic air contaminants by the CARB on July 25, 1986, and OEHHA has concluded that dioxins are a potential human carcinogen with no identifiable threshold. In 1992, CARB identified 1,3-butadiene as a toxic air contaminant. PAHs and PCBs are considered hazardous air pollutants by the U.S. EPA and in 1993, CARB also identified them as toxic air contaminants.

Public Hearing Information

• Formal Regulatory Documents
• Board Hearing Transcripts - February 21, 2002
• Staff Presentation

The Draft version of the California Air Resources Board 2025 Annual Network Plan, covering monitoring operations in 26 Air Districts in California is now available for public review. The public review period ends on June 22, 2025. Any comments or questions regarding the network report should be directed to:

Jin Xu, Manager, Air Quality Analysis Section

Federal regulations require that the Annual Network Plan be submitted to the U.S. Environmental Protection Agency (U.S. EPA) after the 30-day public review period. Any comments received during the review period will be forwarded to the U.S EPA along with the Annual Network Plan.

Draft Annual Network Plan

Draft Appendices

Webinar

CARB Annual Network Plan

Note that there are 35 air districts in California. Nine air districts that conduct ambient are quality monitoring are developing separate Annual Network Plans covering the ambient monitoring within their jurisdictions. This Annual Network Plan covers the 26 air districts for which the local air agencies are not drafting a separate report.

For additional information on California's monitoring network, visit Monitoring Site Information.

Appendix E: Figures and Tables in Chapters 1 through 4

1. Figures
2. Tables
3. Glossary of Air Quality Terms

Appendix D: Natural Sources

1. Introduction
2. Biogenic Sources
3. Geogenic Sources
4. Wildfires

Figures in Appendix D

D-1 Statewide Biogenic Emissions
D-2 Wildfires 2001 - 2010

Tables in Appendix D

Appendix C: Surface Area, Population, and Average Daily Vehicle Miles Traveled

1. Introduction
2. California Population and Vehicle Miles Traveled
3. Surface Area by County
4. Population and Vehicle Miles Traveled by County, Air Basin, and Air District

Figures in Appendix C

No figures in Appendix C

Tables in Appendix C

Appendix B: County Level Emissions and Air Quality by Air Basin

1. Introduction
2. Emission Inventory
   1. 2012 Emissions
   2. VOCs
   3. NO_x
   4. SO_x
   5. PM_2.5
   6. PM₁₀
   7. Diesel PM
   8. Ammonia (NH₃)
3. Air Quality
   1. Great Basin Valleys Air Basin
   2. Lake County Air Basin
   3. Lake Tahoe Air Basin
   4. Mojave Desert Air Basin
   5. Mountain Counties Air Basin
   6. North Central Coast Air Basin
   7. North Coast Air Basin
   8. Northeast Plateau Air Basin
   9. Sacramento Valley Air Basin
   10. Salton Sea Air Basin
   11. San Diego Air Basin
   12. San Francisco Bay Area Air Basin
   13. San Joaquin Valley Air Basin
   14. South Central Coast Air Basin
   15. South Coast Air Basin

Figures in Appendix B

No figures in Appendix B

Tables in Appendix B

Appendix A: Air Quality Trend Data by Pollutant: Ozone, PM_2.5, CO, NO₂, SO₂

1. Introduction
2. Ozone
3. PM_2.5
4. Carbon Monoxide
5. Nitrogen Dioxide
6. Sulfur Dioxide

Figures in Appendix A

No figures in Appendix A

Tables in Appendix A

Chapter 4: Regional Trends and Forecasts

1. Introduction
2. South Coast Air Basin
   1. Introduction
   2. Emissions Trends and Forecasts
      1. Basinwide Trends/Population and Vehicle Miles Traveled
      2. Ozone Precursor Emissions
      3. Directly Emitted PM_2.5 Emissions
      4. Diesel PM Emissions
      5. Ammonia Emissions
   3. Air Quality
      1. Ozone
      2. Particulate Matter (PM_2.5)
      3. Nitrogen Dioxide
3. San Francisco Bay Area Air Basin
   1. Introduction
   2. Emissions Trends and Forecasts
      1. Basinwide Trends/Population and Vehicle Miles Traveled
      2. Ozone Precursor Emissions
      3. Directly Emitted PM_2.5 Emissions
      4. Diesel PM Emissions
      5. Ammonia Emissions
   3. Air Quality
      1. Ozone
      2. Particulate Matter (PM_2.5)
      3. Nitrogen Dioxide
4. San Joaquin Valley Air Basin
   1. Introduction
   2. Emissions Trends and Forecasts
      1. Basinwide Trends/Population and Vehicle Miles Traveled
      2. Ozone Precursor Emissions
      3. Directly Emitted PM_2.5 Emissions
      4. Diesel PM Emissions
      5. Ammonia Emissions
   3. Air Quality
      1. Ozone
      2. Particulate Matter (PM_2.5)
      3. Nitrogen Dioxide
5. San Diego Air Basin
   1. Introduction
   2. Emissions Trends and Forecasts
      1. Basinwide Trends/Population and Vehicle Miles Traveled
      2. Ozone Precursor Emissions
      3. Directly Emitted PM_2.5 Emissions
      4. Diesel PM Emissions
      5. Ammonia Emissions
   3. Air Quality
      1. Ozone
      2. Particulate Matter (PM_2.5)
      3. Nitrogen Dioxide
6. Sacramento Valley Air Basin
   1. Introduction
   2. Emissions Trends and Forecasts
      1. Basinwide Trends/Population and Vehicle Miles Traveled
      2. Ozone Precursor Emissions
      3. Directly Emitted PM_2.5 Emissions
      4. Diesel PM Emissions
      5. Ammonia Emissions
   3. Air Quality
      1. Ozone
      2. Particulate Matter (PM_2.5)
      3. Nitrogen Dioxide

Figures in Chapter 4

South Coast Air Basin

4-1 Air Basin Map
4-2 Percent Growth in Population and VMT
4-3 NO_x Emission Trends
4-4 VOC Emission Trends
4-5 Directly Emitted PM_2.5 Emission Trends
4-6 Diesel PM Emission Trends
4-7 Ammonia Emission Trends
4-8 Ozone Air Quality Trend
4-9 Ozone Contour Map - 1992
4-10 Ozone Contour Map - 2011
4-11 PM_2.5 Air Quality Trend
4-12 NO₂ Air Quality Trend

San Francisco Bay Area Air Basin

4-13 Air Basin Map
4-14 Percent Growth in Population and VMT
4-15 NO_x Emission Trends
4-16 VOC Emission Trends
4-17 Directly Emitted PM_2.5 Emission Trends
4-18 Diesel PM Emission Trends
4-19 Ammonia Emission Trends
4-20 Ozone Air Quality Trend
4-21 PM_2.5 Air Quality Trend
4-22 NO₂ Air Quality Trend

San Joaquin Valley Air Basin

4-23 Air Basin Map
4-24 Percent Growth in Population and VMT
4-25 NO_x Emission Trends
4-26 VOC Emission Trends
4-27 Directly Emitted PM_2.5 Emission Trends
4-28 Diesel PM Emission Trends
4-29 Ammonia Emission Trends
4-30 Ozone Air Quality Trend
4-31 Ozone Contour Map - 1992
4-32 Ozone Contour Map - 2011
4-33 PM_2.5 Air Quality Trend
4-34 NO₂ Air Quality Trend

San Diego Air Basin

4-35 Air Basin Map
4-36 Percent Growth in Population and VMT
4-37 NO_x Emission Trends
4-38 VOC Emission Trends
4-39 Directly Emitted PM_2.5 Emission Trends
4-40 Diesel PM Emission Trends
4-41 Ammonia Emission Trends
4-42 Ozone Air Quality Trend
4-43 PM_2.5 Air Quality Trend
4-44 NO₂ Air Quality Trend

Sacramento Metropolitan Area

4-45 Air Basin Map
4-46 Percent Growth in Population and VMT
4-47 NO_x Emission Trends
4-48 VOC Emission Trends
4-49 Directly Emitted PM_2.5 Emission Trends
4-50 Diesel PM Emission Trends
4-51 Ammonia Emission Trends
4-52 Ozone Air Quality Trend
4-53 PM_2.5 Air Quality Trend
4-54 NO₂ Air Quality Trend

Tables in Chapter 4