English (en-CA) · EVENING EDITION · ENVIRONMENT AND HEALTH

Wildfire smoke is sharply worsening air quality in southern Ontario. Environment and Climate Change Canada forecasts very high risk in Toronto overnight.

Updated July 15, 2026 at 9:10 p.m. ET · About 3 minutes

The facts

• At 5 p.m., the federal government forecast a maximum of 10+, or very high risk, for Toronto Wednesday night.
• The maximum is forecast at 9, high risk, Thursday, then 8 Thursday night and 4, moderate risk, Friday.
• People with heart or lung conditions, children and older adults are among those most vulnerable.
• For Montreal and Quebec City, official forecasts reviewed Wednesday evening remained at level 2, or low risk.

The context

The smoke is coming from active fires in central Canada, including Ontario. It reduces visibility and can carry fine particles over long distances. Conditions may change quickly with the wind, so forecasts should be checked before outdoor activity.

Why it matters

People at risk should reduce or reschedule strenuous outdoor activity. The general population should consider doing the same if symptoms such as coughing or throat irritation occur. Keeping windows closed when smoke is heavy and using a cleaner indoor-air space can also reduce exposure.

This is a health forecast, not medical advice. Seek professional care for serious or persistent symptoms.

Sources

• Environment and Climate Change Canada — Toronto AQHI, forecast issued July 15, 2026 at 5 p.m. ET.
• Environment and Climate Change Canada — Montreal AQHI, accessed July 15, 2026.
• Reuters, July 15, 2026 report on wildfire smoke.

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