After planning out how the sensor would work, the pair turned to the resources at MakerLabs, a community workspace in their native Vancouver, British Columbia, for further development. “We used basically everything in the building,” says Hart. A group of physicists renting space on the top floor worked with them to build an accurate air pollution monitor smaller than anything on the market. Industrial designer Afshin Mehin helped make the device beautiful. The size of an Oreo cookie, the sensor measures particulate matter, a key air pollution component, as well as ultraviolet light.