Nearly half of U.S. kids are breathing unhealthy air, report says. These are the cleanest and most polluted cities. - CBS News

A new American Lung Association report finds that ozone and particle pollution make the air unhealthy for about 152 million Americans, including nearly half of U.S. children and teens. The analysis highlights widespread unhealthy air across many cities and links particle pollution — much of which can come from wildfire smoke — and ozone formed during heat events as key drivers. Those findings amplify public-health concerns raised by recent research tying prolonged wildfire smoke exposure to increased cancer risk and by forecasts of persistent heat and dangerous wildfire conditions that can worsen smoke and pollution.