Framing
Air pollution is the second leading risk factor for death globally. In 2021, air pollution (mostly particulate matter of diameters 2.5 micrometers and smaller, or PM2.5) contributed to 8.1 million deaths around the world. Particulate matter and ozone (O3), which are both U.S. EPA criteria air pollutants, pose the greatest health risks, which is why we decided to focus on these pollutants as air pollution indicators. Sources of PM2.5 include vehicle exhaust, agriculture and livestock, construction, and industrial processes. In California in recent years, smoke from wildfires has caused spikes in PM2.5 pollution. Ground-level ozone is formed when nitrogen oxides (NOx) and volatile organic compounds (VOCs) are exposed to sunlight. NOx and VOCs similarly come from vehicles, power plants, refineries, and other sources.
Policy spotlight
* The Mulford-Carrell Air Resources Act of 1967 created the California State Air Resources Board (CARB). Since its creation, CARB has set state standards and monitored air quality. * With Assembly Bill 617 of 2017, CARB established the Community Air Protection Program to improve local air quality measurements and reduce exposure in the communities most affected by air pollution. * Advanced Clean Cars (ACC) and the 2035 Gas Car Ban of 2022 are estimated to reduce over 4,000 tons of fine particulate matter (PM2.5) and other harmful air pollution such as greenhouse gases from 2026 to 2040. * AB 32 Global Warming Solutions Act of 2006 is an important piece of legislation setting greenhouse gas emissions reduction targets, often linked with local air quality improvement efforts.
Justice lens
* Redlining from the 20th century continues to impact Black, Hispanic, and low-income populations today. Formerly redlined neighborhoods have higher pollution burdens, less vegetation, and elevated temperatures, compared to city averages. * Studies consistently show a higher air pollution burden for low-income and people of color communities. According to a 2021 CalEnviroScreen Analysis of Race and Ethnicity, people of color, especially Latino and Black people, disproportionately reside in areas with high pollution burden in California. * A comprehensive 2024 study conducted by UC Berkeley public health researchers found that minority populations were more likely to be exposed to elevated concentrations of PM2.5 and nitrogen dioxide (NO2), however pollution burden seems to be improving over time. Unfortunately, the Indigenous or Native American demographic group was not disaggregated in these studies.
Source & citation
Content on this page draws from The California Doughnut Snapshot and Report, used under CC-BY 4.0.
Aritza, A. and Kraus-Polk, J. et al. (2025). The California Doughnut Snapshot and Report. Zenodo. https://doi.org/10.5281/zenodo.17540639