Evaluation of low-cost optical particle counters for environmental and occupational exposures

ECU Author/Contributor (non-ECU co-authors, if there are any, appear on document)

Swastika NA Regmi (Creator)

Institution

East Carolina University (ECU )

Web Site: http://www.ecu.edu/lib/

Abstract: Low-cost optical particle counters are easy to operate, portable, compact in size, inexpensive, and most widely used in particulate matter (PM) monitoring. This study evaluated the accuracy, bias, and precision of four commercially available low-cost sensors (OPC-N3 from Alphasense, SPS30 from Sensirion, AirBeam2 from HabitatMap, and PMS A003 from Plantower) for measuring mass concentrations of particulate matter in environmental and occupational settings. The mass concentrations (PM1, PM2.5, PM4, and PM10) reported by low-cost sensors and a medium-cost device pDR-1500 were compared with GRIMM MiniWRAS as the reference instrument. Three different aerosols were generated: Salt, Arizona Road Dust, and Poly-alpha-olefin-4 oil using three different aerosol generation systems. In environmental settings, for all aerosol types, the mass concentrations measured by OPC-N3 (r=0.99), SPS30 (r=0.99) were highly correlated with the reference instrument, while the AirBeam2 (r=0.65-0.97) and PMS A003 (r=0.22-0.97) were less correlated for environmental settings. In occupational settings, for all aerosol types, the mass concentration measured by all the low-cost sensors and medium-cost device, OPC-N3 (r=0.88-1.00), SPS30 (r=0.99), AirBeam2 (r=0.99), PMS A003 (r=0.96-0.99) and pDR-1500 (r=0.99) were highly correlated with the reference instrument for occupational settings. However, a significant variation in slope and intercept values was observed between environmental and occupational settings. For environmental settings, 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, 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 bias were considerably high for all aerosol types and PM metrics. For occupational settings, all the low-cost sensors and pDR-1500 showed a high bias for all PM metrics. For intra-instrument precision, SPS30 exhibited high precision for salt within the recommended range (CV<10%) compared to other low-cost sensors and aerosol types. Among all the sensors, AirBeam2 and PMS A003 demonstrated extremely low precision compared to OPC-N3 and SPS30 for all aerosol types and different concentrations in environmental settings. Similarly, for occupational settings, SPS30 showed high precision for all aerosol types and PM metrics, but the remaining low-cost sensors showed low precision with %CV exceeding the recommended range (CV<10%) for all aerosol types. The findings suggest that SPS30 and OPC-N3 can provide a reasonable estimate of mass concentrations if calibrated differently for environmental and occupational settings using site-specific calibration factors.

Additional Information

Publication

Thesis

Language: English

Date: 2020

Keywords

Optical Particle Counters, Low-cost Sensors, Particulate Matter Sensors, Performance Evaluation, Air Quality Monitoring Sensors

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