Since 2000, the American Lung Association’s “State of the Air” report has examined air pollution in communities nationwide, first looking solely at ozone, which at ground level is the main ingredient in smog, and in 2004 adding particle pollution, including dust and smoke. This year’s report is based on 2019-2021 data from the U.S. Environmental Protection Agency’s Air Quality System.

Although 23 of the 25 cities with the worst daily particle pollution were in the West, the cities with the worst year-round particle pollution were all over the country. These cities, such as Detroit and Pittsburgh, have high power plant emissions and local industrial and mobile pollution sources, the report says.

Bakersfield, California, which is north of Los Angeles, was the most polluted city for daily particle pollution and tied for most year-round particle pollution with Visalia, California, situated in the San Joaquin Valley.

This year’s report shows falling ozone levels nationwide, which it attributes to emissions controls and, particularly in the Eastern U.S., the economy’s transition away from coal.

The report named Los Angeles the U.S. city with the worst ozone pollution, which may not come as a surprise considering it has held that position every year but one since the first State of the Air report.

Climate change is complicating Western communities’ efforts to address ozone pollution, the report says, because it contributes to weather conditions associated with higher ozone levels, such as higher temperatures; dry, sunny skies; and more frequent air stagnation.

“Simply, climate change is undercutting the progress we would have made,” the report says.

People of color were more than 3.7 times as likely as White people to live in a county with failing grades for daily particle pollution, year-round particle pollution and ozone pollution, the report says.

In addition to taking the steps recommended in the report, local governments could protect people’s health during wildfires by teaching them how to monitor and respond to unhealthy air quality, said Liz Scott, the American Lung Association’s national director, advocacy, healthy air, in an interview. She also said local governments could establish community centers with air filtration systems and ensure people have access to protective equipment such as N95 masks.

Read the full article about the air pollution gap by Ysabelle Kempe at Smart Cities Dive.