Poorer, more polluted Toronto neighbourhoods have higher childhood asthma rates: Study

TORONTO — Children living or born in poorer or more polluted Toronto neighbourhoods are more likely to develop childhood asthma, new research suggests.

Researchers from St. Michael’s Hospital identified clusters of high rates of atopic asthma rates — asthma related to allergies:

  • Parkdale-Little Portugal;
  • The intersection of the Don Valley Parkway and the westbound Gardiner Expressway;
  • The intersection of the DVP and Highway 401;
  • and Cliffside-Scarborough village.

“Such clusters support the notion that early life factors at the neighbourhood level are relevant to the development of childhood asthma,” said Dr. Ketan Shankardass, the study’s lead author.


About 70 per cent of the children involved in the study moved out of their birth neighbourhood, suggesting that air pollution during pregnancy and shortly after birth was related to a higher likelihood of developing asthma later in life.

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While the areas were concentrated around heavily trafficked roadways, researchers said traffic-related pollution wasn’t the only factor. “Persistent air pollution” from factories in industrial areas of Scarborough contributed to high asthma rates, they found.

Income was a factor, too, Shankardass said: Families in the areas of Parkdale-Little Portugal and Scarborough with high childhood asthma rates also have lower incomes than the Toronto-area median.

The houses in these neighbourhoods are also older, which makes them host to environmental hazards mold and cockroaches.

Shankardass advises people living in areas with higher air pollution to make an effort to spend time in parks and green spaces with fresh air.

“There’s a lot of things families can do to reduce the impact of that type of hazard: They can take care when they decide where they’re going to spend time outdoors,” he said.

“They should try to find places where they’re not directly breathing in a lot of traffic pollution, if you can.”

This study was funded by Health Canada, Natural Resources Canada and the Canadian Institutes for Health Research.