Influence of particle properties and environmental factors on the performance of typical particle monitors and low-cost particle sensors in the market of China

Abstract

The performance of particle measurements based on three types of principles, including tapered element oscillating microbalance (TEOM), beta attenuation monitor (BAM) and light scattering, were investigated with different types of particle (braize, arizona dust and polystyrene spheres), particle sizes (1.1, 2.0, 2.5 and 3.0 μm), and environmental factors (temperature, relative humidity and relatively high particle concentration). Specifically, two middle-cost monitors (LY, LL) and three low-cost sensors (PT, YT, SF) with light scattering were considered.Good correlations with gravimetric were all observed on three principle instruments with three particle types at laboratory tests, except for less concerned intercepts did not meet the requirements of standard HJ 653–2013. Particle properties showed negligible effect on the instrumental measurements based on BAM and TEOM, commonly as high-cost monitors. Interestingly, middle-cost monitors were found to be more sensitive to particle properties versus low-cost sensors using calibration dusts with various properties. Moreover, obvious impacts of particle sizes were observed for all tested light-scattering monitors and sensors. In addition, different trends of sensors measuring PM10/PM2.5/PM1.0 with the increase of particle sizes indicated the poor particle recognition of light scattering principle. Expectedly, poor correlations of sensors were observed in ambient experiments compared with laboratory experiments due to the effect of complex environmental factors. Relative humidity (RH) and temperature (T) were proposed to express synergistic effects on measurements by sensors. Meanwhile, poor correlation and zero drift of YT sensors after high particle concentration exposure experiments revealed high particle concentrations would result in the pollution of low-cost sensors due to the lack of self-cleaning function. In conclusion, to evaluate the performance of sensors for future standard instrumental developments more accurately, both indoor and outdoor assessments should be taken out. The data acquired in this study could provide information for future evaluation of the performance of particle monitors and sensors based on light scattering principle.