Assessing inter-sensor variability and calibration of low-cost IAQ sensors through co-location with reference devices

Low-cost sensors for measuring different airborne pollutants have become rapidly available to consumers to assess air quality in the built environment. However, its quick emergence has resulted in concerns about reliability and performance. This study analyzed the performance of twenty single-brand low-cost sensors, Fosensor FS00802G, at varying particle concentrations. Testing took place in a controlled chamber and 0.5% of sodium chloride (NaCl) was used as the aerosol to conduct two experiments. Two PM 2.5 concentration ranges were tested: 0 to 2000 µg⋅m-3, and 0 to 7000 µg⋅m-3.

All twenty sensors, had low accuracy and high precision, and low intra-sensor variability. However, the sensors consistently underreported PM2.5 and PM10, and over-reported PM1 mass concentrations at low concentrations with respect to the reference instruments (DustTrak and Aerodynamic Particle Sizer; TSI). Despite the variations in quantitative agreements, at lower concentrations, the sensors had a high coefficient of determination with the reference instruments and were able to detect sources at higher concentrations. This suggests that the sensors can be calibrated prior to sampling in high-concentration environments; however, frequent calibration may be required for highly polluted areas.