Low-cost air quality monitors Modeling and characterization of sensor drift in optical particle counters

Low-cost sensors for mass deployment or personal use must often be calibrated to account for poor mechanical and electrical tolerances. Equally important to the initial calibration, however, is the characterization of sensor drift. This paper presents a method for evaluating drift for inexpensive optical air quality sensors. A total of 29 calibrated sensors were circulated through a public lending library over a period of approximately 7.5 months. Following deployment, usage data was collected and each device was recalibrated. The resulting data is used to model drift as a function of time between calibration.