These US cities have the worst air quality this year

The view of downtown Los Angeles is obscured by smog, heat and haze from Panorama Nature Preserve in Fullerton Wednesday, April 10, 2024. (Allen J. Schaben / Los Angeles Times via Getty Images)

Nearly half of Americans are living in places with unhealthy levels of pollution, despite decades of efforts to reduce what’s causing it, a new report found. 

The American Lung Association’s "State of the Air" 2025 report found that 156.1 million Americans live in places that get failing grades for ozone or particle pollution. That’s nearly 25 million more than last year and more than any report in the past 10 years. 

What’s causing more air pollution?

Dig deeper:

Extreme heat, drought and wildfires are contributing to worsening levels of air pollution across much of the U .S ., "exposing a growing proportion of the population to ozone and particle pollution that put their health at risk," the report says. 

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The report also found that once again, "the burden of living with unhealthy air is not shared equally." 

What they're saying:

"Research has shown that communities of color are disproportionately exposed to unhealthy air and are also more likely to be living with one or more chronic conditions that make them more vulnerable to air pollution, including asthma, diabetes and heart disease," the authors wrote. "Notably, Hispanic individuals are nearly three times as likely as white individuals to live in a community with three failing grades."

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2025’s Most Polluted Cities by Ozone

Big picture view:

The "State of the Air" report looks at two of the most widespread and dangerous air pollutants: fine particles and ozone. The data are collected at official monitoring sites across the United States by federal, state, local and Tribal governments. This year’s report uses data from 2021, 2022 and 2023, the most recent three years of nationwide air pollution data publicly available.

Local perspective:

In "State of the Air" 2025, the metropolitan areas that ranked worst in the country for ozone pollution, short-term particle pollution and year-round particle pollution haven’t changed since last year. 

Bakersfield, California, ranks worst for short-term particle pollution for the third consecutive year. It’s the sixth year in a row that Bakersfield has had the worst levels of year-round particle pollution. 

Los Angeles, meanwhile, is still the city with the worst ozone pollution in the nation, as it has been in 25 of the 26 years of American Lung Association Reporting. 

Air pollution health effects

Why you should care:

Breathing in polluted air over a long period of time can cause respiratory illness, Alzheimer’s disease and cancer, said Fatimah Ahamad, chief scientist and air pollution expert at Malaysia-based Sunway Centre for Planetary Health. The World Health Organization estimates that air pollution kills around 7 million people each year.

The Source: This report includes information from the American Lung Association's State of the Air 2025 report and The Associated Press. 

Environment