Quirks & Quarks

Pollution sniffing investigators find air near roads is high in contaminants

A report found a 'soup' of pollutants from traffic on major Canadian roads.

A report found a 'soup' of pollutants from traffic on major Canadian roads.

Dr. Greg Evans led the national study on traffic emissions near major roadways in collaboration with Environment and Climate Change Canada, the Ontario Ministry of the Environment, Conservation and Parks, and Metro Vancouver. (Roberta Baker, University of Toronto Engineering)

A report on air pollution published this week found a 'soup' of pollutants from traffic on major Canadian roads. The researchers think this should raise serious health concerns as a third of Canadians live near a busy road.

The pollutants include nitrogen oxides, ultrafine particles, black carbon, metals, carbon monoxide and carbon dioxide. These materials have been associated with a wide range of health issues, including asthma, cancer and cardiovascular problems. 

Dr. Greg Evans, a professor in Chemical Engineering at the University of Toronto and the director of the Southern Ontario Centre for Atmospheric Aerosol Research, led the study. He and his team set up six air quality stations in Toronto and Vancouver next to major roads that included expressways, main city roads like Yonge Street in Toronto and Clark Drive in Vancouver, and a major truck route. 

They found that large diesel trucks are the leading polluters, despite their comparitively small numbers on roads and highways. Currently, Canada doesn't have standards for diesel emissions from trucks, according to Evans. But based on levels of black carbon, the concentration of diesel exhaust near major roads have exceeded standards that have been established elsewhere. For example the levels were higher than guidelines proposed for workers in the Netherlands.

"[The levels we found] could indicate there's an increased incidence of cancer," said Evans.

While newer vehicles have advanced pollution control systems, Evans says many older trucks lack these systems, and some unscrupulous operators tamper with the treatment system to save on fuel costs. 

"They just don't appreciate that when their truck drives by a playground, the children on that playground are going to inhale those emissions about 40 seconds later," said Evans. 

Other sources of pollutants highlighted in the study include non-tail pipe emissions generated by brake and tire wear.  These include particles of various metals that make up the brakes, and these levels have risen in recent years as people have purchased heavier vehicles which cause faster brake wear.

Evans says all three levels of government need to work together to address these problems. His suggestions include removing trucks from roads near playgrounds or only allowing well-maintained trucks to use those roads.

"There are easy ways we can improve now that we're aware of the problem." 



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