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.

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.

Air quality alerts are in effect on Tuesday in 10 states as toxic smoke from hundreds of wildfires burning in Canada continues to waft into the United States, creating hazy, gray skies over major metropolitan areas, including New York City.