The AirNut sensor is a handheld device that provides real-time measurements of fine particles (PM2.5), Carbon Dioxide (CO2), temperature (C) and relative humidity (%).

AirNut uses light-scattering to measure particles smaller than 2.5 micrometers in aerodynamic diameter. It converts the signal to a PM2.5 mass concentration, sends the data to a server via WiFi and displays the readings on a website and a cell phone application.