To Study Pittsburgh's Air Pollution, Activists Turn Bikes Into Smog-Sensing Machines

Dec 17, 2015

Sometimes in the field of citizen science, scientific instruments can start to look a little like that science fair project you did back in the 6th grade.

“Yeah, this is Home Depot creativity night gone wild,” Jamin Bogi says, looking down at the air quality monitors he’s been handing out to volunteers. With plenty of PVC pipe, Velcro and rubber cement, these monitors definitely have a DIY flare. But the air quality sensor inside is actually pretty high tech.

“They have a laser inside that shoots around and bounces off of particulate matter,” he says. “And then it counts the number of particles in the air.”

This story was produced by The Allegheny Front, a public radio program based in Pittsburgh that covers environmental issues. 

For the last couple of years, Bogi has been giving these monitors out to cyclists as part of a project run by the Group Against Smog and Pollution, or GASP, a nonprofit based in Pittsburgh, a city with some of the worst air pollution in the country. Bogi mounts the monitors to volunteers' handlebars, and then people just ride their bikes all around the city the way they normally would. Meanwhile, those lasers take an air sample once every 10 seconds to track the pollution along the route.

GASP's air quality monitor is a mix of high and low tech: PVC pipes, Velcro and rubber cement make up a DIY bracket that holds a sensor that measures air quality using lasers.
Credit Lou Blouin / The Allegheny Front

“Then we take all the data and put it on a map and color code it," Bogi says. "And in the end, someone on a bicycle or walking or jogging can get a quick glimpse of where might have less pollution, where might have more pollution, and make choices based on that data.”

An online map that helps people plan less-polluted exercise routes is just one of the payoffs of the project. GASP recently did a more targeted ride to try to get a handle on just how much of the city’s air pollution comes from vehicles as opposed to factories and power plants. For this, they had to get a little creative: They took advantage of an event in Pittsburgh called Open Streets. During this event, several major roads were opened up to bikes, street yoga and just about anything but cars.

“So we had our volunteers put our monitors on their bikes and go up and down the route twice. They did that during an Open Streets event. And they did it on another day when traffic was back to normal.”

And the result? GASP’s monitors found pollution levels were about four times higher with cars than without. And this kind of street-level data from specific sites can have big implications as the city plans new infrastructure. For example, Bogi says they’re seeing that having protected bike lanes that separate bikes from cars by just a few feet—or planting tree buffers between bike trails and nearby highways—can significantly reduce your pollution exposure.

GASP hopes the data they’re collecting can help justify projects like that. For now, it’s more rides and more data—and hopefully unveiling a version 2.0 of their monitor that relies on a little less rubber cement.

To read more about GASP's bicycle air-monitoring program, or to view their interactive air-quality map, visit