The Grey Bruce Region is under a special air quality statement.
Environment Canada says the smoke from forest fires is causing or expected to cause poor air quality and reduced visibility.
“Air quality and visibility due to wildfire smoke can fluctuate over short distances and can vary considerably from hour to hour,” says the agency.
It adds as smoke levels increase, health risks increase as well.
The agency recommends limiting time outdoors and to consider reducing to rescheduling outdoor sports, activities and events.
The smoke may result in eye, nose and throat irritation, as well as headaches or a mild cough.
“More serious but less common symptoms include wheezing, chest pains or severe cough. If you think you are having a medical emergency, seek immediate medical assistance,” says Environment Canada.
Environment Canada says the smoke may last until Monday for parts of southern Ontario.