As wildfire smoke blankets parts of Ontario, bringing poor air quality to Toronto, health experts say Canadians should be paying as much attention to air quality forecasts as they do the weather.

While smoke-filled skies are an obvious warning sign, some of the most harmful pollutants are invisible.

“Sometimes it’s obvious when there is smoky air outside with soot on your garden furniture and barbecue,” says Dr. Samir Gupta, a respirologist and clinician scientist at St. Michael’s Hospital and the University of Toronto. “A lot of times the air quality is poor, but you can’t actually see it, and that’s where we worry even more.”

One of the biggest concerns during wildfire smoke events is fine particulate matter, known as PM2.5. These microscopic particles can travel deep into the lungs, and some “nanoparticles” are small enough to enter the bloodstream. What makes PM2.5 especially concerning is that people cannot see it or smell it, meaning they may be exposed without realizing. For people living with chronic disease, that exposure can increase the risk of serious health effects. 

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Air quality affects more than your lungs

Wildfire smoke is often associated with respiratory illness, but Gupta says the effects can extend well beyond the lungs. Through the bloodstream, PM2.5 can affect really any organ in the body.

People living with asthma and chronic obstructive pulmonary disease (COPD) face an increased risk of flare-ups during these events. Wildfire smoke can also increase the risk of cardiovascular events, including heart failure, heart attacks and even stroke.

Gupta notes that wildfires can affect pregnancy, diabetes control, and cause complications of kidney disease. While the lungs, heart and brain are considered the organs most affected by wildfire smoke and extreme heat, exposure may also have an impact on the placenta, developing fetus, skin and other organs. 

Know the warning signs

For people wondering when poor air quality becomes a medical concern, Gupta points to one symptom in particular: shortness of breath.

“Shortness of breath can signal that the lungs or heart are struggling to cope with smoke exposure,” Gupta says. “In some cases, a person’s first asthma or respiratory flare-up may occur during a wildfire smoke event.”

Anyone experiencing new or worsening breathing difficulties should seek medical attention.

Make air quality part of your daily routine

Most people check the forecast before deciding what to wear or whether to bring an umbrella. Gupta believes checking the Air Quality Health Index (AQHI) should become just as routine.

Available through Environment Canada forecasts and many weather apps, the AQHI can help people decide whether to modify their plans, spend less time outdoors, or avoid strenuous activities.

“You should be looking at the air quality to decide how much time you’re going to spend outside,” Gupta says. Even healthy individuals may want to rethink outdoor exercise when air quality is poor.

If you have a chronic condition, have a plan

People living with chronic illnesses should consider speaking with their healthcare provider about how air pollution may affect their condition and what steps to take when air quality deteriorates.

Gupta recommends asking:

  • How does poor air quality affect my condition?
  • What symptoms should I watch for?
  • At what air quality level should I modify my activities?
  • Do I have an action plan if my symptoms worsen?

Wildfire smoke events frequently occur alongside periods of extreme heat, creating additional challenges for people with chronic disease and those taking medications that can affect the body’s ability to cope with hot weather.

The combination of smoke and heat can place additional strain on the body, making it especially important for vulnerable individuals to plan ahead and understand their risks.

A new reality

As wildfire season becomes a more regular part of Canadian summers, awareness and preparation are increasingly important. 

Gupta’s message is simple: Know your personal tolerance for poor air quality and adjust activities accordingly. Air quality should be treated much like temperature or UV levels – a daily health indicator that can help people make safer decisions about their activities and, in turn, reduce the health risks associated with smoke exposure. After all, some of the biggest risks from poor air quality are the ones people can’t see.  

By Hannah Nickle

Photo by Kevin Van Paassen

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