air quality index

As the sun rose on Madison, Wis., Thursday morning, the air quality was measured at 242 — a "very un...

Smoke from wildfires in Canada is again blanketing parts of the U.S. with a thick haze that's reduci...

A version of this story originally ran on Feb. 5, 2021 This week, millions of Americans are anxiousl...

Millions of people along the East Coast and further inland woke up to a cloud of hazy air Wednesday ...