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Laboratory Evaluation of Low-cost Optical Particle Counters for Environmental and Occupational Exposures
SINAN SOUSAN, Swastika Regmi, Yoo Min Park, East Carolina University
Abstract Number: 143
Working Group: Aerosol Exposure
Abstract
Low-cost optical particle counters effectively measure particulate matter (PM) mass concentration and are easy to operate, portable, and compact. However, calibration differences between environmental and occupational settings have not been demonstrated. This study evaluated four commercially available PM low-cost sensors (OPC-N3 from Alphasense, SPS30 from Sensirion, AirBeam2 from HabitatMap, and PMS A003 from Plantower) in environmental and occupational settings. The mass concentrations (PM1, PM2.5, PM4, and PM10) of three aerosols (salt, Arizona road dust, and Poly-alpha-olefin-4 oil) were measured and compared with the GRIMM MiniWRAS as the reference instrument. For all aerosol types, the OPC-N3 and SPS30 were highly correlated (r=0.99) compared to the AirBeam2 (r=0.65-0.97) and PMS A003 (r=0.22-0.97), for environmental settings. In contrast, the OPC-N3 correlation varied (r=0.88-1.00), but the SPS30 and AirBeam2 exhibited high correlation (r=0.99), as did the PMS A003 (r=0.96-0.99), for occupational settings. Response significantly (p <0.001) varied between environmental and occupational settings for most particle sizes and aerosol types. Biases varied by particle size and aerosol type. For environmental settings, the SPS30 exhibited substantially low bias for salt aerosol for PM1 (bias=-6.10) and PM2.5 (bias=-0.82) measurements among all the low-cost sensors. In contrast, the OPC-N3 bias was low for dust (PM1=-4.3 and PM2.5=-10.63) and oil (PM1=1.88 and PM2.5=-8.92). AirBeam2 and PMS A003 biases were considerably high for all aerosol types and PM metrics. For occupational settings, all the low-cost sensors showed a high bias for all PM metrics. For intra-instrument precision, SPS30 exhibited high precision for salt within the recommended range (CV<10%) for environmental and occupational settings compared to other low-cost sensors and aerosol types. These findings suggest that SPS30 and OPC-N3 can provide a reasonable estimate of PM mass concentrations if calibrated differently for environmental and occupational settings using site-specific calibration factors.