Inequitable Exposure to Air Pollution from Vehicles in California (2019)

Who bears the burden?
We quantified Californians' exposure to dangerous air pollution. Particulate matter disproportionately affects Californians of color and low-income communities.

En español: La injusta exposición a la contaminación del aire por tráfico vehicular en California  

Latinos, African-Americans, Asian-Americans and low-income communities are exposed to substantially more air pollution from cars, trucks and buses than other demographic groups in California. For many years, this has been a known fact among affected communities, whom have experienced first hand the dangerous impacts of air pollution, like lung and heart ailments, asthma, and premature death.

We quantified the exposure of these groups to particulate matter (PM2.5)  from on-road sources and compared it to other demographic segments. Beyond the scope of this analysis, emissions from ports, agricultural practices, dust, and other sources are well known to contribute to poor air quality and negative health outcomes for affected areas. 

What is PM2.5 pollution?  Fine particles — less than one-tenth the diameter of a human hair — pose a serious threat to human health, as they can penetrate deep into the lungs. Some PM2.5 is formed during the burning of gasoline and diesel in an engine, while additional PM2.5 is created in the atmosphere from the reaction of exhaust gases and other air pollutants. Diesel exhaust is a major contributor to PM pollution. 

Key Findings 

  • On average, African American Californians are exposed to PM2.5 pollution that is 43 percent higher than that for white Californians.
  • Latino Californians are exposed to PM2.5 pollution 39 percent higher, on average, than that for white Californians.
  • The lowest-income households in the state live where PM2.5 pollution is 10 percent higher than the state average.
  • The highest income households live where PM2.5 pollution is 13 percent below the state average.
  • Californians living in households without a personal vehicle are also exposed to much higher levels of vehicle pollution than other households because they tend to live in urban areas surrounded by vehicle traffic.

Explore the data 

Click on the map to see the exposure to air pollution from vehicles in different parts of the state. You can zoom-in to the street level, and click on areas of interest to view the exposure to air pollution as compared to the state average, and their demographic composition. 

Download the data > 

Opportunities to Reduce Harmful Impacts of Vehicle Use

Electrification of vehicles: Electrifying both passenger and freight vehicles could greatly reduce emissions. Battery-electric and fuel cell vehicles in particular have no tailpipe emissions (however, there are minor amounts of PM2.5 emissions from tire and brake wear) and completely avoid the need for, and emissions associated with, gasoline refueling.  Electricity generation and hydrogen production can produce emissions; however, California has renewable content standards for both hydrogen for transportation and electricity that will limit additional emissions.  

More efficient and lower-emissions conventional vehicles: More efficient and lower-emission conventional vehicles are also important for reducing air pollution. Gasoline vehicles with higher fuel economy need less refueling, potentially reducing the amount of volatile organic compounds evaporating during refueling and from spillage. And fuel-saving technologies, such as start-stop systems that reduce idling, can also contribute to reduced tailpipe emissions. 

Decrease the amount of driving: Incentivizing driving less is also a potential strategy to reduce harmful air pollution and improve public health. Land use decisions are important to reducing the need for driving, and policies that encourage use of public transit, walking, or biking in the place of private passenger auto use could reduce PM2.5 generation. This is especially true if the transit options are low-emission, such as electric rail and buses. 

Targeted actions: State and local governments must target actions to reduce emissions in and near densely populated neighborhoods and in the communities of color and low-income communities. Existing actions such as California’s Clean Vehicle Rebate Project, low- and zero-emissions vehicle regulations, regional Sustainable Communities Strategies, and the Sustainable Freight Action Plan exemplify steps the state has taken to reduce air pollution from vehicles. Policymakers have also taken specific actions aimed at reducing burdens on the most heavily affected communities, for example, by instituting requirements for the government to invest a minimum percentage of revenue generated from the state’s cap-and-trade program in disadvantaged communities. Clean vehicle incentive programs—which provide greater financial incentives for lower-income households and for deployments in marginalized communities—as well as programs to accelerate the retirement of the oldest, highest polluting vehicles are also being implemented.  

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