Wildfire smoke from the Prairies drifted into Windsor-Essex over the long weekend prompting Environment Canada to issue a special air quality statement.
Due to hundreds of active wildfires, the weather service had a number of air-quality warnings and statements, stretching from eastern British Columbia and into western Quebec, varying in severity.
The statement said air quality and visibility due to wildfire smoke can fluctuate over short distances and can vary considerably from hour to hour.
Environment Canada meteorologist Brian Owsiak said wildfire smoke may persist for the region through Monday.
"Just given the relatively light wind flow through the weekend, and wind just pulling that smoke south, it is possible that it would last through the holiday Monday," Owsiak said.
Owsiak said it's been a summer of wildfire smoke across Canada.
"The smoke is pretty widespread, certainly through the Prairies, and certainly through northern Ontario, far northern Ontario has improved, at least temporarily as winds there are coming from a different direction where the air is cleaner, but most of Ontario right now is seeing a lot of that wildfire smoke and fairly high concentrations of it as well," he said.
Owsiak said youth, the elderly, and anyone with compromised lung functions are most at risk and should take extra precautions.
"If people can, try to stay indoors, try to reduce physical activity if at all possible, just because the concentrations of smoke are getting high, and it can be dangerous to a persons health," Owsiak said.
Air quality warnings require the air-quality health index rating to be at 10 or higher for at least six consecutive hours.
Meanwhile, special air-quality statements are issued when poor air-quality index ratings are around a seven, but less than 10.
-With files from The Canadian Press