February 5, 2019

Latinos and African-Americans in California Breathe about 40 Percent More Vehicle Pollution than White Californians

Scientists Quantify Extent of Pollution Disparity Throughout State

OAKLAND, Calif. (February 5, 2019)—African American and Latino Californians are exposed to about 40 percent more fine particulate matter (PM2.5) from cars, trucks and buses than white Californians, according to an analysis released today by the Union of Concerned Scientists (UCS).

The study looked at emissions from vehicle tailpipes and vehicle refueling, and estimated pollution exposure at the census tract level. The study found African Americans are exposed to 43 percent higher levels, and Latinos 39 percent higher levels of air pollution from vehicles than white Californians, respectively.

Some PM2.5 is formed from burning gasoline or diesel in an engine, but most PM2.5 is formed when pollutants react in the atmosphere. Among all air pollutants, PM2.5 has the biggest impact on human health. The particles are so small – 20 times smaller than the width of a human hair – they can penetrate deeply into the lungs and bloodstream. Exposure to PM2.5 is linked to both acute and chronic heart and lung ailments, asthma attacks, increased hospitalizations, lung cancer and death.

“Residents in the communities most affected have known for generations there was a disproportionate amount of air pollution in their neighborhoods,” said David Reichmuth, senior engineer at UCS and author of the new study. “This modeling allows us to quantify the extent of the disparity across the state. California has made enormous strides over the past several decades to reduce overall pollution from vehicles, but this data shows people of color still breathe higher amounts of pollution.” On average, across the state, the study found air pollution is lower where the percentage of white Californians is higher.

The large disparity in pollution exposure between racial and ethnic groups was similar to disparities found between geographic areas and income levels in California. Residents of Los Angeles County are exposed to 60 percent more vehicle pollution than the state average and 250 percent more than residents of the San Francisco Bay Area. However, pockets of the Bay Area, such as West Oakland or San Jose, have dirty air on par with average areas of Los Angeles, according to the study. Meanwhile, across the entire state, Central Bakersfield has the highest concentration of PM2.5 from vehicles.

The lowest earning California households (earning less than $20,000 per year) are exposed to 25 percent more PM2.5 pollution than the highest earning California households (earning more than $200,000 per year). The study also found that Californians in households without a personal vehicle are exposed to 19 percent more PM2.5 pollution than the state average because they tend to live in urban areas surrounded by traffic.

“People who deliberately or because of financial circumstances do not own a car and do not contribute directly to vehicle air pollution experience more of that pollution. The irony should not be lost on local leaders and clean air advocates,” said Reichmuth.

Vehicle emissions also include carbon dioxide that contributes to climate change.

The UCS analysis recommends continuing and expanding current state policies aimed at reducing vehicle pollution in over-burdened communities to lessen the severe disparity between racial groups and people of various income levels across the state.

“We have the advantage in this state of already having innovative rules and policies in place that have made us leaders in electrifying transportation and reducing emissions,” said Reichmuth. “But we need to do more to make sure all Californians breathe clean air. With an unabated housing crisis in this state and more dense development coming near high-traffic corridors, we should prioritize clean vehicle programs that benefit the communities most burdened by air pollution.”

The Union of Concerned Scientists puts rigorous, independent science to work to solve our planet's most pressing problems. Joining with people across the country, we combine technical analysis and effective advocacy to create innovative, practical solutions for a healthy, safe, and sustainable future.