Do you ignore heat and smog alerts and still jog outdoors?

If you are healthy, this is probably fine, but here’s a tip from an expert in air pollution: “Jog in the morning because exposure is quite a lot lower on highly polluted days,” says Dr. Greg Evans, professor of engineering and applied chemistry at University of Toronto and director of the Southern Ontario Centre for Atmospheric Aerosol Research.

“Exposure to pollutants is the worst in the mid to late afternoon.” The bonus of exercising in the morning, of course, is that it’s cooler and heat stress isn’t as much of a factor.


Are you a commuter? Evans warns that the suburbs don’t necessarily have cleaner air. “Often, air quality in surrounding communities is as bad or worse than downtown Toronto. For example, Oakville or Oshawa are not necessarily better.”

Air pollution is thought to exacerbate respiratory and heart problems, so people who are vulnerable should heed warnings carefully. His advice for the rest of us?

“Take extra water breaks. The heat and humidity coupled with air pollution mean you need to take it a bit easier. We’re not invincible,” says Evans.

Air quality in Ontario has actually improved over the last 10 years. That’s the good news. The bad news is we’re not seeing the equivalent reduction in health effects. Over time, it takes less pollution to make people sick.

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