Evaluation of Cairpol and Aeroqual Air Sensors in Biomass Burning Plumes

Cairpol and Aeroqual air quality sensors measuring CO, CO2, NO2, and other species were tested on fresh biomass burning plumes in field and laboratory environments. We evaluated the sensors by comparing 1 min sensor measurements to collocated reference instrument measurements. The sensors were evaluated based on the coefficient of determination (r(2)) between the sensor and reference measurements, as well as by the accuracy, collocated precision, root mean square error (RMSE), and other metrics. In general, CO and CO2 sensors performed well (in terms of accuracy and r(2) values) compared to NO2 sensors. Cairpol CO and NO2 sensors had better sensor-versus-sensor agreement (i.e., collocated precision) than Aeroqual CO and NO2 sensors of the same species. Tests of other sensors (e.g., NH3, H2S, VOC, and NMHC) provided more inconsistent results and need further study. Aeroqual NO2 sensors had an apparent O-3 interference that was not observed in the Cairpol NO2 sensors. Although the sensor accuracy lags that of reference-level monitors, with location-specific calibrations they have the potential to provide useful data about community air quality and personal exposure to smoke impacts.