Air quality statement for Ottawa lifted but heat warning remains in effect

Hazy conditions at the Central Experimental Farm in Ottawa. July 15, 2025. (Ted Raymond/CTV News Ottawa)

The air quality in Ottawa is starting to improve after a smoky, hazy start to the day.

A special air quality statement that came into effect Monday was lifted at around 10 a.m. Tuesday, as air quality showed signs of improving.

A heat warning remains in effect for Ottawa, with hot, humid weather and a high humidex in the forecast.

The forecast for Tuesday is sunny with local smoke. The high is 32 C with a humidex of 40. The UV index is 9, or very high.

The air quality health index (AQHI) at 10 a.m. was 5, or a moderate risk, after briefly dropping to 4 an hour earlier. It is forecast to fall to 3, or low risk, on Wednesday.

“You may experience mild and common symptoms such as eye, nose and throat irritation, 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,” Environment Canada says of the smoke.

The heat, however, also presents risks.

“Watch for the early signs of heat exhaustion in yourself and others. Signs may include headache, nausea, dizziness, thirst, dark urine and intense fatigue. Stop your activity and drink water,” the heat warning says.

Meteorologist Crawford Luke says if you have to choose between staying indoors to avoid the haze or going outside to find a way to cool off, choose to cool off.

“The public health messaging is to treat the heat warning as the more serious one,” he told CTV News Ottawa on Monday. “If that means you need to jump in a lake or a pool or something to keep cool, that’s the recommendation from them. It’s the more immediate health threat.”

The sky will remain clear, but hazy, Tuesday night. The overnight low is 20 C.

Wednesday’s forecast is mainly sunny with a high of 33 C and a humidex of 41.

The heat warning for Ottawa is expected to end Thursday night. Thursday’s forecast is cloudy with a 30 per cent chance of showers and a high of 30 C, while Friday’s high is 26 C, which is closer to the seasonal norm.

With files from CTV News Ottawa’s Kimberley Johnson