Smoke from Canadian wildfires is causing air quality concerns for millions of Americans in the Midwest and Northeast.

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.

The smoke floating over the border shared between America and Canada is now impacting air quality in states as far south as Texas, AirNow's data shows. The EPA has declared the air quality in states ...