A new report on air quality across the U.S. offers a cloudy prognosis on the long-term health of about 156 million residents who live in areas that received an "F" in smog and soot pollution.

Since 2000, the American Lung Association has released an annual State of the Air report analyzing air quality data across the United States. This year’s report, released on Wednesday, found the highest number of people exposed to unhealthy levels of air pollution in a decade.

Air pollution levels keep getting worse for more people in the US, according to a new report, and experts say the Trump administration’s proposed deregulation plans will make it even harder for people to get clean air.