(503d) Development of a Calibration Chamber to Evaluate the Performance of Low-Cost Particulate Matter Sensors

Abstract

Low-cost particulate matter (PM) air quality sensors are becoming widely available and are being increasingly deployed in ambient and home/workplace environments to provide highly resolved spatiotemporal PM concentrations. However, PM measurements from these sensors are often of questionable quality, and the sensors need to be characterized individually for the conditions of use. In this study, we designed and evaluated a cost-effective calibration chamber capable of continuously providing a uniform PM concentration to multiple low-cost PM sensors. The chamber development and assessment were based on a Computational Fluid Dynamics (CFD) model and a rigorous experimental protocol. We also used this new chamber to calibrate 242 Plantower PMS 3003 PM sensors from two manufacturing batches (I and II) by exposing them to two aerosol types: ammonium nitrate and alumina oxide. Our CFD models and experiments demonstrated that the chamber is capable of providing uniform PM concentration to 8 PM sensors at once within 6% error and with excellent reliability (intraclass correlation coefficient > 0.771). The study identified two malfunctioning sensors and showed that the remaining sensors have high linearity compared to a DustTrak reference monitor that was calibrated for each aerosol type (R²>0.978). Finally, the results revealed statistically significant differences between the responses of batch I and II sensors to the same aerosol (P-value<0.001) and the batch I sensors to the two different aerosol types (P-value<0.001). This chamber design and evaluation protocol can provide a useful tool for those interested in laboratory characterization of low-cost air quality sensors in a systematic and rigorous manner.

Drs. K. Kelly and P.-E. Gaillardon have an interest in the company Tetrad: Sensor Network Solutions, LLC, which commercializes solutions for environmental monitoring.