Toronto’s Air Just Became the Second Worst on Earth – Here’s Why

A blazing wildfire spreads in Canada. Photo by Landon Parenteau from Pexels

Between July 14 and 15, 2026, intense wildfire activity across Canada triggered widespread smoke transport across central and eastern regions. As a result, severe air quality impacts were reported in Ontario and Quebec. On July 15, 2026, Toronto ranked as the 2^nd most polluted major city globally (IQAir), as wildfire smoke caused a sharp deterioration in air quality. 

CAMS (Copernicus Atmosphere Monitoring Service) aerosol forecasts showed very high wildfire smoke concentrations. Specifically, aerosol optical depth (AOD, a measure of how much smoke is in the atmosphere) values reached approx. 0.8–1.0 across parts of Ontario and Quebec. For comparison: values between 0.1 and 0.3 indicate relatively clear air. This indicates that the physical pressure and weight of smoke particles (atmospheric loading) is increasing, contributing to reduced visibility, persistent haze, and elevated health risks. Children, elders, pregnant individuals, and people with existing respiratory and cardiovascular conditions are among the most vulnerable. 

What is Happening? 

• As of 15 July 2026, approximately 148 active wildfires were reported by the Ontario Ministry of Natural Resources. Of these, 69 were classified as not under control. 
• The air in Ontario and Quebec is currently extremely smokey from wildfires, with pollution levels measured at 0.8–1.0 on the Aerosol Optical Depth (AOD) scale through the CAMS. 
• Largest fires: 
  • Red Lake: ~3,079 hectares burned 
  • Lake Nipigon: ~ 1,200 hectares burned 
• Smoke impacts are spreading across northwestern Ontario, including Thunder Bay, Dryden, Kenora, and Red Lake, with smoke transport affecting broader areas of Ontario and Quebec. 

Why This Keeps Getting Worse: Climate Change and Extreme Fire Weather? 

Canada’s wildfire seasons are becoming more dangerous as hotter temperatures & drier conditions create landscapes that are easier to ignite and harder to protect. Hotter conditions dry out forests and vegetation, leaving more dry material that helps fires start and spread quickly. Longer dry periods, reduced snow cover, and more frequent heat extremes are creating conditions where wildfires can grow larger, last longer, and threaten communities, wildlife, and the places people depend on. 

Scientific research indicates that as the climate warms, western and northern Canada will face more extreme fire risks, meaning hotter & drier conditions that make wildfires more likely and harder to control. By the end of the century (2071–2100), many regions could see 20–50% more extreme fire weather days under moderate warming, and over 50% more under higher warming. Thus, this would lead to longer wildfires seasons, more intense fires, poorer air quality, and greater risks to people and ecosystems. 

How Does the Arctic Make Canada Warmer? 

Canada’s wildfire risk is also being reshaped by rapid changes in the Arctic. Rapid Arctic warming is increasing wildfire risks in Canada by causing earlier snowmelt, warmer temperatures, and drier landscapes. In northern regions with permafrost (ground that stays completely frozen at or below 0°C for at least 2 years), thawing ground can cause the soil to harden & trigger vegetation dryness, ultimately leading to more fire vulnerable ecosystems.  

Climate warming is the main cause of permafrost melting, science indicating that in some parts of the Northwest Territories, permafrost could decline from 67% today to 2% by 2100 if warming continues. 

Wildfires can speed up permafrost thaw by burning away vegetation and exposing frozen ground to heat.  Studies in northern Canada show that this can increase the thawed soil layer by about 0.5 metres, making the landscape change, and more prone to future wildfires.  

What Does This Mean for Communities and Ecosystems? 

Human Health Impacts 

• Smoke exposure can trigger breathing problems, worsen asthma, increase respiratory infections, and place extra stress on the heart and lungs. 
• Smoke from wildfires can travel far from the fire zone, affecting air quality in towns and cities far from where fires are burning. 
• Wildfire smoke contains dangerous air pollution, including tiny particles (fine particulate matter, PM₂.₅) that can enter deep into the lungs. 

Environmental Impacts 

• Large wildfires damage forests, wildlife habitats, and the natural places that communities depend on. 
• More frequent and intense wildfires can worsen air pollution, damage ecosystems, and add pressure to natural systems already affected by an overheating planet. 

Economic and Social Impacts 

• Smoke-filled skies can disrupt daily activities, limit outdoor work and recreation, and affect local businesses and tourism. 
• Communities face rising costs from emergency response, healthcare needs, and recovering after wildfire events. 
• Repeated wildfire emergencies place growing pressure on firefighters, healthcare workers, and emergency responders. 

Urgent Response Needed 

What Needs to Change? 

• Strengthen wildfire preparedness through better early warning systems, fire monitoring, and evacuation plans that help protect communities.  
• Protect people from wildfire smoke through better smoke forecasts, clean-air spaces, and clear health guidance.  
• Reduce carbon pollution that is driving rising temperatures and increasing wildfire risks. 
• Protect forests and natural areas through better land management, ecosystem restoration, and Indigenous-led fire stewardship practices (including traditional knowledge, cultural burning, and forest restoration practices to reduce wildfire risks and protect ecosystems). 

What Can YOU Do? 

• Check local air quality alerts during wildfire smoke events (like IQAir in Canada the Government of Canada’s Weather Information service, specifically the Local Air Quality Health Index (AQHI)page). 
• Protect your health by limiting outdoor activity when smoke levels are unhealthy.  
• Use reliable sources for wildfire and air quality information (such as CAMS – Copernicus Atmosphere Monitoring Service).  
• Share accurate information about how hotter conditions, drought, and wildfire smoke are affecting the places where we live. 

Read more: Extreme weather events | Health risks | Climate Risks Daily 

Original source: Wildfire Map Spotlight: Northwestern Ontario wildfires, Canada | IQAir USA