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

Smoke from wildfires in Manitoba, a Western province facing its worst fire season in 30 years, has created hazardous air quality conditions across Eastern Canada and the United States.

With wildfire smoke in the forecast, track the drop in air quality across dozens of PurpleAir sensors with our live, updating maps! New data arrives every 30 minutes. Current air quality at dozens of individual PurpleAir sensors, with latest estimated smoke extent.