Canadian wildfire smoke is affecting air quality across parts of the U.S. Here's who's at risk and how to protect yourself.

Millions of people in the Great Lakes, Northeast and mid-Atlantic states muddled through another day of unhealthy air from uncontrolled wildfires on Friday.

The thick smoke enveloped the nation’s capital in a gloomy, eerie haze and prompted Major League Baseball’s Cleveland Guardians to postpone their game against Pittsburgh Pirates in Ohio.