Aerosol Chamber Characterization for Commercial Particulate Matter (PM) Sensor Evaluation

The negative impact of PM2.5 exposure has encouraged the development of scattering-based PM sensors for monitoring the PM level spatially and temporally. These PM sensors excel in terms of cost, operating power, and compactness, but the performance of each model needs to be evaluated individually. The evaluation of a PM sensor can be conducted inside an aerosol chamber by measuring the PM concentration in time series using both the sensor and reference monitors. However, earlier experimental processes were time-consuming, as a long time was needed to decrease the PM concentration by loss mechanisms. We designed an aerosol chamber by introducing an output airflow rate to decay the PM concentration more quickly. The characterization of the chamber yielded an empirical equation to describe the PM concentration decay profile, which can be used to predict the measurement time and the number of data points. The chamber was then utilized to evaluate three PM sensors (Sharp GP2Y1010AU0F, Winsen ZH03A, and Novafitness SDS011). A condensation particle counter (TSI, 3025A) and particle sensor (Honeywell, HPMA115S0-XXX) were employed as reference monitors. The evaluation determined the linearity, calibration curve, and precision of the PM sensors. The evaluated models showed excellent linearity, with R2 values above 0.956. The least square and RMA correlation of the evaluated PM sensors demonstrated the best linearity achieved at a low PM measurement range (0–400 µg m–3). As the Winsen ZH03A and Novafitness SDS011 sensors had coefficients of variation below 10%, both of the sensors have an acceptable precision according to the EPA standard.