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Breathe easier: Smog-free days the norm as city's air quality improves

It wasn’t that long ago that Toronto was plagued with smog alerts, but the times they are a changin’.

Last year the city was smog alert free for the first time in 20 years and with only one special air quality statement issued so far this year, it seems like those days may be a thing of the past. But why?

Smog warnings and advisories are issued by the Ontario Ministry of the Environment when the air quality index is forecasted to reach or exceed 50. Although the amount of smog varies from location to location, according to their data, air quality has improved steadily since 1988.

“It is a trend that we have been seeing over the last several years,” Ministry spokesperson Kate Jordan explained.

Some experts credit the closure of coal-fired power plants and initiatives like Drive Clean with reductions of primary pollutants.

“Drive Clean does reduce smog-forming pollutants by more than one-third,” Jordan said. “As well, investments in public transit and stronger air standards.”

The Drive Clean program was created by the province in 1999 in an effort to reduce harmful exhaust emissions.

Jordan said the province’s move to renewable energies such as solar and wind has also helped the process.

According to the ministry, the contaminants that create smog are released during the combustion of fossil fuels in our vehicles, power plants, factory boilers and homes. They are also released by industrial processes, the evaporation of liquid fuels and the use of solvents and other volatile products such as oil-based paints. And more than half of our smog problem comes from pollution sources in the United States.

But it isn’t just government initiatives that have helped reduce smog days. Weather has a lot to do with it, CityNews meteorologist Adam Stiles explained.

“If you get a stagnant pattern in the atmosphere where there’s not a lot of storms coming through and cleaning the air and changing the wind direction, when you’re locked under a big ridge of high pressure, that’s typically when you start to see the poor air quality,” he explained.

Toxic pollutants from factories in the Rust Belt (Detroit, Akron, Cleveland, etc.) can quickly make things worse for air quality in Toronto if the wind is right.

“You need to tap into that southwest flow to really tap into all that gunk in the air,” Stiles said. “When you start adding multiple cities and pollutants, even though you’re travelling it over further distances, it still gets caught into the air pattern.”

Stiles said it gets particularly bad when there’s a steady stream of southwesterly wind, which the GTA hasn’t had this summer.

“We just really haven’t had a prolonged pattern,” he explained. “If you have it locked in for a couple of days, you’re going to start to see the air quality diminishing.”

“Having no smog days is a good thing. We had a very cool July. Our July was way below seasonal, a lot of northerly wind days, a lot of easterly wind days,” he continued.

Here are some negative effects air pollution and smog can have:

  • Make it harder to breathe
  • Irritate your lungs and airways
  • Worsen chronic diseases such as heart disease, chronic bronchitis, emphysema and asthma
  • Each person reacts differently to air pollution. Children, seniors and those with diabetes, heart or lung disease are most sensitive to the adverse health effects of air pollution.


Those with diabetes or lung and heart issues are at higher risk when smog is high. As well seniors and children must take precautions when going out on days with high levels of air pollution.