Laboratory Evaluation of Low-Cost Optical Particle Counters for Environmental and Occupational Exposures.

Swastika Regmi,Sinan Sousan,Yoo Min Park

doi:10.3390/s21124146

Abstract

Low-cost optical particle counters effectively measure particulate matter (PM) mass concentrations once calibrated. Sensor calibration can be established by deriving a linear regression model by performing side-by-side measurements with a reference instrument. However, calibration differences between environmental and occupational settings have not been demonstrated. This study evaluated four commercially available, low-cost PM sensors (OPC-N3, SPS30, AirBeam2, and PMS A003) in both settings. The mass concentrations of three aerosols (salt, Arizona road dust, and Poly-alpha-olefin-4 oil) were measured and compared with a reference instrument. OPC-N3 and SPS30 were highly correlated (r = 0.99) with the reference instrument for all aerosol types in environmental settings. In occupational settings, SPS30, AirBeam2, and PMS A003 exhibited high correlation (>0.96), but the OPC-N3 correlation varied (r = 0.88–1.00). 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. SPS30 and OPC-N3 exhibited low bias for environmental settings, but all of the sensors showed a high bias for occupational settings. For intra-instrumental precision, SPS30 exhibited high precision for salt for both settings compared to the 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.

Highlights

Air pollution is one of the leading causes of death in both developing and economically developed countries
Sensors 2021, 21, 4146For salt aerosol, the mass concentrations representing environmental settings of PM1, PM2.5mc, and PM10 (Figure 2) and occupational settings of PM1, PM2.5, PM4mc, and PM10 (Figure 3) for the low-cost sensors and pDR were compared to the MiniWRAS measures
The SPS30 showed a strong correlation with the reference instrument, with PM1, PM2.5, PM10 (Figure 3) for the low-cost sensors and pDR were compared to the MiniWRAS

Summary

Introduction

Air pollution is one of the leading causes of death in both developing and economically developed countries. The World Health Organization [1] estimated that 7 million deaths worldwide annually are due to air pollution, which results in stroke, ischemic heart disease, lung cancer, chronic obstructive pulmonary disease (COPD), and acute respiratory infections. Particulate matter (PM) is one of the six criteria for air pollutants regulated under the National Ambient Air Quality Standards established by the U.S Environmental. PM poses a significant threat to human and environmental health. Exposure to PM is associated with various cardiovascular and respiratory diseases, and the overall impact of PM on the human body depends on particle size, concentration, and chemical composition [3]

Methods

Results

Discussion

Conclusion