Abstract View
Effect of Relative Humidity on the Performance of Five PM Sensors
PENG WANG, Feng Xu, Huanqin Wang, Da-Ren Chen, Virginia Commonwealth University
Abstract Number: 138
Working Group: Instrumentation and Methods
Abstract
With the increasing awareness of adverse PM effect on the public health, air quality, atmospheric visibility and climate change, PM sensors with the initial costs significantly less than scientific ones have been widely proposed in the air quality monitoring network to measure the PM mass concentration. The study on the performance of these cost-effective PM sensors has been reported in literature. Many of these studies investigated low-cost sensors under the lab setting with relative humidity well controlled. However, the humidity is always present in the ambient. The effect of relative humidity on the readouts of low-cost PM sensors has not been reported yet. In this work, the performance of five widely used PM sensors were investigated using lab-generated particles under various humidity. As the reference, a tapered element oscillating microbalance (TEOM) was included. The effect of particle hygroscopicity, size and components on the performance of selected PM sensors was systemically studied. It was found the relative humidity has negligible effect on the selected PM sensor readings for hydrophobic particles, while measurable effect was observed on the readings of selected PM sensors when the relative humidity to some extent. More, the reading of PM sensors shows a different linear relationship with the TEOM reading for hydrophilic particles of different sizes and compositions under different relative humidity. Our investigation suggests that Low-cost PM sensors required to be calibrate under different relative humidity conditions and the recording of relative humidity of the ambient is necessary when applied PM sensors in the fields (for getting accurate PM data).
Keywords: Low-cost sensors; Relative humidity; Hygroscopicity; Particulate components