• 05.04.16

This App Helps Cyclists Avoid A City’s Most Polluted Streets

Riders in Toronto can now plan the cleanest route, even if it isn’t the fastest.

This App Helps Cyclists Avoid A City’s Most Polluted Streets
Photo: Flickr user Simon Carr

As if having to deal with distracted drivers and even-more distracted pedestrians wasn’t dangerous enough, cyclists also have to suck in the exhaust fumes of the cars that choke our city roads. But if you ride in Toronto, you can use a handy new tool to plan the cleanest route from A to B, although it will seldom be the most direct.


The irony of bike lanes is that they are almost always on busy roads, because those are the roads where we need more protection. But bike lanes also attract cyclists, which means that infrastructure designed to protect us is also forcing us into some of our cities’ dirtiest air.

Civil engineering professor Marianne Hatzopoulou, of Toronto University, studied the problem by fitting air monitors to cyclists and measuring the results of riding down 380 miles of Montreal bike lanes. Then she did the same for Toronto, in a study that monitored the air quality in summer and winter, only using cars instead of bikes. The cars drove for six hours a day, in two three-hour stints, and Hatzopoulou took the data and turned it into an online app—the Clean Ride Mapper—which lets you plan the cleanest route through the city.

The cleanest route isn’t always the quietest. The architecture of the streets makes a big difference, with pollution building up between tall buildings and dissipating better in more open areas, even though the traffic is denser. That’s why Hatzopoulou’s map is helpful, even if you know the city well. It shows both the fastest route and the cleanest, so you can choose your trip to balance the two. In fact, for frequent cyclists, the most useful part of the map might be the overlay which shows the levels of ultra-fine particles. Thus, you can update your own internal bike map to avoid the worst roads and favor the cleanest.

The real problem, though, is cars in cities. No matter how much we encourage cycling, or other forms of city-friendly transport, there are still too many cars. “We’re encouraging densification and also encouraging all modes of active transportation,” Hatzopoulou told Toronto Metro, “but we’ve done nothing to reduce the number of cars on the road. So all we’re doing is putting cyclists and pedestrians closer to the pollution.”

About the author

Previously found writing at, Cult of Mac and Straight No filter.