"Despite decades of environmental efforts, over 40% of Americans — more than 137 million people — live in cities and states with poor air quality, a new report says. And, in addition to cars and factories, wildfires are increasingly contributing to unhealthy air.
For the past 22 years, the American Lung Association has produced its annual State of the Air report, which analyzes the air quality on a local level for communities across the country. This year's study found that more Americans were exposed to unhealthy air, at times deemed hazardous, compared to previous years.