Heat, wildfire smoke combine to create dangerous conditions across southwestern Ontario

Heat, wildfire smoke combine to create dangerous conditions across southwestern Ontario

Air quality warning joins heat alert as smoke pushes health risks higher across the region

A heat wave and wildfire smoke are combining to create potentially dangerous conditions across parts of southwestern Ontario on Wednesday.

Environment Canada issued its first air quality warning of the year Wednesday morning as a multi-day heat warning remained in effect across the region.

"Smoke from forest fires in northwestern Ontario will cause poor air quality across much of southern Ontario. Poor air quality will begin this morning and may last into tonight," Environment Canada wrote in its alert. "As smoke levels increase, health risks increase. Limit time outdoors. Consider reducing or rescheduling outdoor sports, activities and events."

Forecasters expect air quality to deteriorate throughout the day across much of southwestern Ontario, including Middlesex, Lambton and Huron counties, as well as parts of Bruce County.

London's air quality health index rating is expected to peak at eight on Wednesday, 10+ on Wednesday night, 10 on Thursday and 10+ on Thursday night.

Index readings of seven through 10 indicate a high risk.

Wildfire smoke can cause eye, nose and throat irritation, headaches and coughing. More serious symptoms include wheezing, chest pain and severe coughing.

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People at greatest risk include older adults, pregnant people, infants and young children, people with chronic illnesses or respiratory conditions, and those who work outdoors.

Environment Canada advises people to limit strenuous outdoor activity, keep windows and doors closed when possible, and prioritize staying cool during the heat event. If time outdoors is unavoidable, a well-fitting N95 respirator or equivalent can help reduce exposure to fine smoke particles.

Environment Canada's air quality warning does not list an expected end time.

The air quality warning comes as southwestern Ontario remains under a heat warning.

London is expected to reach a high of 33 C on Wednesday, with a humidex of 42. The heat warning is expected to end Wednesday evening for London and surrounding areas, although communities closer to Lakes Erie and Ontario could remain under the warning into Thursday or Friday.

Environment Canada says hot, humid conditions can worsen air quality and increase the risk of heat-related illnesses.

Officials urge residents to drink water frequently, avoid strenuous activity during the hottest parts of the day, check on vulnerable neighbours and family members, and never leave children or pets inside parked vehicles.

For more on how locals are coping with the heat, and how you can stay safe, you can read CBC London's story on the situation here.