Canada fires trigger air quality alerts in upper US

 Wildfire smoke chokes Edmonton, Canada, in 2023.
Wildfire smoke chokes Edmonton, Canada, in 2023.

What happened

Several states across the northern U.S. were placed under air quality alerts on Monday as smoke from dozens of wildfires burning throughout western Canada pushed south.

Who said what

More than 140 active fires in British Columbia, Alberta, Saskatchewan and the Northwest Territories have burned at least half a million acres this spring, much of it "over the past week," AccuWeather meteorologist Brandon Buckingham said. In the U.S., fine particle levels tied to the wildfire smoke are "expected to reach the red air quality index (AQI) category, a level considered unhealthy for everyone" in southern Minnesota, said the Minnesota Pollution Control Agency. Similar alerts were in effect across Montana, the Dakotas and Wisconsin.

Air pollution from wildfires is considered particularly dangerous because tiny particles in smoke, "about 4% of the diameter of an average human hair, are small enough to reach deep inside the lungs," NBC News said.

What next?

This is "likely to be a very bad forest fire season," Canadian Prime Minister Justin Trudeau said. "People are worried what the summer might bring."