Multiple U.S. states and Canadian provinces are experiencing poor air quality from wildfire smoke. Here's where.

Wildfire smoke degrades air quality in swaths of Ontario, with Toronto ranking among the worst in the world on Monday.

Canadian wildfire smoke lingers in Michigan. Officials issued an air quality advisory in southeast Michigan for July 15.

The Bay Area Air Quality Management District and Alameda County District Attorney Ursula Jones Dickson filed a joint civil ...