The Flatburn "Open Source City Scanner" Looks to Put High-Accuracy Air Quality Monitors Everywhere

Researchers at the Massachusetts Institute of Technology (MIT), the University of Colorado Denver, the Norwegian University of Science and Technology, and Tufts University have released an open source "city scanner" with which they hope to build detailed maps of air quality around the world.

"The goal, explains Carlo Ratti, director of the Senseable City Lab at MIT where the project was developed, "is for community groups or individual citizens anywhere to be able to measure local air pollution, identify its sources, and, ideally, create feedback loops with officials and stakeholders to create cleaner conditions."

The heart of the initiative is Flatburn, a low-cost yet highly-accurate air quality sensor which can be used anywhere — from being installed on buildings to being mounted to the roof of a car. Powered by a battery topped up by a solar panel, the Flatburn detectors have already proven capable: testing in 2021 showed sensors deployed in New York and Boston could keep up with considerable more expensive alternatives while measuring particulate matter (PM) and nitrogen dioxide levels in the atmosphere, when calibrated using a novel machine learning model.

"After following their deployment for a few months we can confidently say our low-cost monitors should behave the same way [as standard detectors]," says An Wang, co-author of the paper detailing the project. "We have a big vision, but we still have to make sure the data we collect is valid and can be used for regulatory and policy purposes."

Even prior to this, though, the team is eager to see the device in the hands of citizen scientists — and has released its design for all to build. "Hopefully with the release of the open source Flatburn we can get grassroots groups, as well as communities in less developed countries, to follow our approach and build and share knowledge," Wang explains of the thinking behind the release.

The open source Flatburn is based around a Particle Boron development board, which provides a Nordic nRF52840 microcontroller and cellular modem, connected to sensors including temperature, humidity, gyroscope, and accelerometer. The main unit connects to sensor board which houses a Bosch BME280 humidity sensor and an Alfasense Analog Front End (AFE) board with sensors for monitoring PM and nitrogen dioxide pollution levels as well as noise pollution. Everything is then tidied up in a 3D-printed housing, with optional magnets for mounting to vehicles — a harsh environment the team admits reduces a Flatburn's operational lifespan to around six months.

More information on Flatburn is available on the Senseable City Lab website, while the design files, firmware, schematics, and 3D-printable chassis files are all available on GitHub under the permissive MIT license.