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“Receiving this appointment is an opportunity to advance research in an area of growing concern for rapidly expanding world cities,” said Hatzopoulou, who was named CRC in Transportation and Air Quality. The CRC program aims to help Canada attract and retain research leaders in engineering and the natural sciences, health sciences, humanities and social sciences. (Photo by Tyler Irving)

Cyclists face a difficult dilemma: on one hand, cycling is good for your health and the environment; on the other, cyclists are more exposed to risks such as accidents and air pollution. New research from U of T Engineering is helping cyclists map cleaner routes to minimize this exposure.

“In general, the benefits of cycling certainly outweigh the risks,” says Professor Marianne Hatzopoulou (CivE). “If you are a healthy person, you are better off to continue cycling than stop.” Nevertheless, when it comes to air pollution, cyclists are at a disadvantage.

“Studies have shown that the concentration of air pollutants tends to be higher inside vehicles than outside them,” says Hatzopoulou. “However, cyclists have a higher breathing rate, which means that they inhale more of these pollutants, and they go deeper into the lungs.”

Such pollutants include ultra-fine particles, as well as nitrogen oxides. Hatzopoulou cites studies associating increased exposure to these pollutants with respiratory problems and certain types of cancer. Her own research has shown that they can even have immediate, measurable effects on the cardiovascular system.

To help address this challenge, Hatzopoulou has created a tool called the Clean Ride Mapper for both Toronto and Montreal. It is essentially a Google Map with an extra layer representing the average concentration of pollutants in a given area, as measured by her team and collaborators. Using this data, algorithms can be constructed to work out not only the shortest route between two points, but also the one that exposes the cyclist to the lowest levels of air pollution.

Hatzopoulou and Anowar outfit a bicycle with equipment to detect the concentration of pollutant particles in the nearby air. (Photo: Tyler Irving)
Hatzopoulou and Anowar outfit a bicycle with equipment to detect the concentration of pollutant particles in the nearby air. (Photo: Tyler Irving)

Hatzopoulou intends to further refine the maps — for example, by incorporating real-time pollution concentrations instead of static data — but lately she has been pondering another question: are such tools actually useful to cyclists?

“There are a lot of factors that influence the choice of a cycling route besides pollution,” she says. “For example, there is safety, separation from traffic, elevation, distance, etc. Which ones would cyclists be willing to trade off in order to decrease their pollution exposure?”

Sabreena Anowar (CivE), a post-doctoral researcher on Hatzopoulou’s team, is working on an answer. She’s designed a survey that proposes several different cycling routes and asks cyclists to choose which one they would prefer.

“No route is perfect,” says Anowar. “They all vary in terms of traffic volume, pollution, elevation, travel time and other attributes.” By measuring which routes people would choose for either a recreational ride or a commuting ride, Anowar and Hatzopoulou hope to better understand how cyclists factor the risks of pollution into their activities. This in turn can help improve the design of tools like the interactive maps.

The survey was launched in Toronto, Montreal, Orlando, Austin, New York in collaboration with researchers in those cities. It will be open at least until June, and Anowar and Hatzopoulou are hoping to get at least 3,000 participants. In addition to their own research, Anowar says that the data could also be useful for city planners. “It will help identify how people value road infrastructure like separated lanes or signage,” says Anowar. “If we build more infrastructure like this, perhaps we can encourage people to cycle more.”

To help Hatzopoulou and Anowar in their research, complete the online survey for either a recreational ride or a commuting ride.

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