Large wildfires in Canada and Minnesota have been sending plumes of smoke into the atmosphere, turning the sky shades of yellow or orange from the U.S. Midwest to the East Coast, and prompting countless air-quality alerts.

Wildfires in Canada are pouring thick clouds of smoke into the US and will usher in unhealthy air quality for millions of people in Northeast and Midwest.

Wildfires in Canada are pouring thick clouds of smoke into the US and will usher in unhealthy air quality for millions of people in Northeast and Midwest.