Smoke from Canadian wildfires set off multiple air quality alerts on Thursday across the Midwest and the Canadian prairies, stretching eastward to Toronto.

“There’s a pretty large swath of smoke actually over the central part of the country right now, and you can see that coming down from central Canada,” said Dave Radell, a meteorologist with the National Weather Service in New York.

The smoke is expected to remain over the northern and central Plains for the next couple of days, he said, adding that there was a chance it could drift toward the East Coast during the later part of the weekend and into early next week.

In Canada, where fires have scorched millions of acres, air quality alerts were issued for multiple provinces, including parts of Manitoba, Ontario and Saskatchewan.

Every air quality monitor in Minnesota is reporting red or unhealthy conditions for everyone, said Matt Taraldsen, supervisory meteorologist at Minnesota Pollution Control Agency.