California has dramatically improved its air quality, but racial disparities persist

Black and Latino communities in California breathe the dirtiest air despite state policies that have successfully restricted vehicle emissions, according to a study.

The study, published in Science Advances on Wednesday, found racial disparities in exposure to vehicle air pollution from 2000 to 2019.

Although fine particulate matter in the air was reduced by 65% in the state during the 19-year period, there is still a disparity in air quality between white communities and communities of color.

The 2000 to 2019 time frame was studied because the state’s regulatory agencies pursued aggressive policies to reduce emissions across the entire on-road vehicle fleet, according to the study.

“California has been remarkably effective at controlling pollution from on-road emission sources, from cars and light-duty trucks to heavy-duty vehicles,” said Joshua Apte, the study’s senior author and an associate professor of civil and environmental engineering at UC Berkeley in a statement. “This is a tremendous win for public health, but our work isn’t done because there’s been no narrowing of the relative gap between the most exposed and least exposed racial and ethnic groups.”

Emissions from cars, or light-duty vehicles in general, are the biggest source of exposure for communities of color, according to the study.

Air pollution exposure disparities are larger by race or ethnicity because of historical racism and racist practices such as housing discrimination and highway relocation. The practices segregated cities and placed high-pollution sources near communities of color, according to the study.

“Highways are disproportionately concentrated in some neighborhoods and not others, and we have to spread that burden around more equally if we want to ultimately get rid of these disparities,” Apte said.

How does air pollution affect people’s health?

Short-term exposure to fine particulate matter in the air can cause premature mortality, increased hospital admissions for heart or lung causes, asthma attacks, and other issues, according to the California Air Resources Board.

Long-term exposure to air pollution has been linked to premature death in people who have chronic heart or lung disease and reduced lung function growth in children, according to the board.

What has California done to reduce air pollution?

California requires cleaner fuels and advanced emissions controls for cars on the road.

California also plans to ban the sale of new gas cars by 2035 and require all vehicles to be electric or hydrogen-powered.

California is the nation’s most populous state, with 39 million people, and accounts for 10% of the U.S. car market.

According to the Department of Energy, California had the most electric vehicles (EVs) in the United States, with approximately 1.2 million registrations as of December 2023.

Will electric vehicles help reduce air pollution?

Even if we transition to all-electric vehicles, air pollution will not be eliminated because tires and brakes will still emit emissions, Apte said.

“As long as vehicles and vehicle emissions are disparately concentrated in overburdened communities, those communities are going to have a higher share of the overall exposure,” he said. “California’s increasing focus on policies that can bring down emissions in places that are historically overburdened, such as accelerated retirement of dirty old vehicles that operate near ports and rail yards, is one way to address these disparities.”