A new study led by researchers at the University of Toronto’s Faculty of Applied Science & Engineering reveals that emissions from nearby traffic can greatly increase concentrations of key air pollutants. The research indicates that almost one-third of Canadians are exposed to a pollutant “soup” – especially during winter while particle emissions from brakes and tires are on the rise.
The findings of the report and its recommendations were discussed at a national meeting in Toronto on November 4, 2019. The research received support from the Natural Sciences and Engineering Research Council of Canada and Canada Foundation for Innovation and was undertaken in collaboration with Environment and Climate Change Canada, Ontario’s Ministry of the Environment, Conservation and Parks, and Metro Vancouver.
The report is the culmination of a two-year study monitoring traffic emissions in Toronto and Vancouver – the two Canadian cities with the highest percentage of residents living near major roads.
“There’s a whole soup of pollutants within traffic emissions,” says Greg Evans, a professor in the U of T department of chemical engineering and applied chemistry who led the study, Evans says that this “soup” of pollutants includes nitrogen oxides, ultra-fine particles, black carbon, metals, carbon monoxide and carbon dioxide. Exposure to these emissions has been associated with a wide range of health issues, including asthma, cancer and cardiovascular mortality.
The following highlights were presented in the report:
- Traffic in cities – Busy roads affect nearby air quality, especially during morning rush hour. The researchers measured concentrations of ultra-fine particles and found that average levels of ultra-fine particles near highways were four times higher than at sites far removed from traffic
- Large trucks – The report highlights the dangers of diesel trucks, which represent a minority of the total trucks on roads and highways, but emit diesel exhaust at disproportionately high levels.
- Wind and winter – Winter weather brings an increase in near-road concentrations of nitrogen oxides and ultra-fine particles. Wind conditions affect pollutant levels; concentrations were up to six times higher when monitoring the downwind side of a major road.
- Tire and brake wear – As brake pads on cars and trucks are worn down, the materials they’re made of turn to dust and go straight into the air. These non-tailpipe emissions, from brakes, tires and the road itself, are increasing because cars are getting larger and heavier.
The report concludes by offering recommendations to all levels of government. Researchers hope the report will lead to establishing a nation-wide road pollution research network that can advise policymakers, engage companies and the public, and lead to standards and laws that will better protect the health of Canadians.
To read the full report, click here.