Toronto is facing a severe environmental crisis as wildfire smoke and an intense heatwave combine to create hazardous conditions across Canada’s largest city. Smoke drifting south from wildfires burning in northwestern Ontario pushed Toronto’s air quality to the worst among major cities worldwide on Wednesday morning, prompting Environment and Climate Change Canada (ECCC) to issue an Orange Air Quality Health Alert.
According to the national weather agency, wildfire smoke has spread across the entire Greater Toronto Area (GTA) and is expected to linger over many communities through Thursday, resulting in persistently poor air quality.
Data from global air quality monitoring platform IQAir showed that, at around 8:00 a.m. on Wednesday, Toronto recorded the world’s most polluted air among major cities. In response, health authorities urged residents to avoid unnecessary time outdoors and refrain from strenuous physical activities to reduce exposure to harmful pollutants.
Medical experts warned that wildfire smoke may cause irritation of the eyes, nose, and throat, as well as headaches and mild coughing. Individuals experiencing more serious symptoms—including shortness of breath, wheezing, chest pain, or persistent coughing—have been advised to seek immediate medical attention.
Authorities also emphasized that older adults, pregnant women, infants and children, and people with chronic respiratory or other underlying health conditions face a higher risk from smoke exposure and should take extra precautions.
Residents have been encouraged to remain indoors whenever possible, keep windows and doors closed, minimize outdoor activities, stay in air-conditioned or cooler environments during the heatwave, and drink plenty of water to avoid dehydration.
Due to deteriorating air quality, the City of Toronto announced that all outdoor field trips and registered outdoor activities under its CampTO summer program would be cancelled, postponed, or moved indoors on Wednesday.
The city also remains under an active heat warning. Temperatures were forecast to reach 33°C, with humidity making it feel closer to 36°C. Environment and Climate Change Canada warned that the combined effects of extreme heat and wildfire smoke pose an elevated risk to public health.
Source: Environment and Climate Change Canada (ECCC).