As Canada grapples with one of its worst wildfire seasons on record, smoke from the blazes have prompted air quality alerts across the U.S.

Smoke from Canadian wildfires is causing air quality concerns for millions of Americans in the Midwest and Northeast.  Air quality alerts were in effect Tuesday in several states, including Michigan and New York.

Millions in the United States are facing another day of hazy skies fueled by hundreds of smoky wildfires burning across North America, impacting air quality in parts of the U.S. and raising health concerns.