Students in STIA 315 built 15 of these monitors using the Maker Hub. Each one costs approximately $150, and is able to monitor PM2.5, a dangerous air pollutant, as well as temperature and relative humidity. The monitors use solar PV for power, and can be used outside. Monitors like this can supplement measurements by EPA-grade air quality monitors (which can cost up to $20,000) and help people improve their understanding of the local air pollution they are exposed to.
STIA 315: International Air Quality Lab