Air quality advisories have been issued for much of northwestern Ontario.
It is because of smoke that is drifting in from nearby fires and others burning across western Canada.
The advisories cover almost all of the remote north, south to some areas in the west end of the Rainy River District, west to the Manitoba border and east to Upsala.
Environment Canada says the elderly, pregnant women, infants, young children and people with an existing illness or chronic health condition could be most susceptible.
People who work outdoors are being advised to reduce or reschedule strenuous activities outdoors and seek medical attention if experiencing symptoms.
Smokey conditions could continue all weekend long in some areas.
