Low-cost sensors for measuring airborne particulate matter: Field evaluation and calibration at a South-Eastern European site.

Low-cost sensors are useful tools for the collection of air quality data, augmenting the existing regulatory monitoring networks and providing an unprecedented opportunity to increase their spatial coverage. This study presents a calibration process of a low-cost PM sensor (PurpleAir PA-II, PAir) in ambient conditions in the city of Patras, Greece, during 18 months of 2017-2018. The hourly PM and PM measurements using the original sensor values were reasonably well correlated (R = 0.