Laboratory Evaluation and Calibration of Three Low-Cost Particle Sensors for Particulate Matter Measurement

Abstract

Particle sensors offer significant advantages of compact size and low cost, and have recently drawn great attention for usage as portable monitors measuring particulate matter mass concentrations. However, most sensor systems have not been thoroughly evaluated with standardized calibration protocols, and their data quality is not well documented. In this work, three low-cost particle sensors based on light scattering (Shinyei PPD42NS, Samyoung DSM501A, and Sharp GP2Y1010AU0F) were evaluated by calibration methods adapted from the US EPA 2013 Air Sensor Workshop recommendations. With a SidePak (TSI Inc., St. Paul, MN, USA), a scanning mobility particle sizer (TSI Inc.), and an AirAssure TM PM 2.5 Indoor Air Quality Monitor (TSI Inc.), which itself relies on a GP2Y1010AU0F sensor as reference instruments, six performance aspects were examined: linearity of response, precision of measurement, limit of detection, dependence on particle composition, dependence on particle size, and relative humidity and temperature influences. This work found that: (a) all three sensors demonstrated high linearity against SidePak measured concentrations, with R 2 values higher than 0.8914 in the particle concentration range of 0-1000 mg/m 3 , and the linearity depended on the studied range of particle concentrations; (b) the standard deviations of the sensors varied from 15 to 90 mg/m 3 for a concentration range of 0-1000 mg/m 3 ; (c) the outputs of all three sensors depended highly on particle composition and size, resulting in as high as 10 times difference in the sensor outputs; and (d) humidity affected the sensor response. This article provides further recommendations for applications of the three tested sensors.

Optical Characterization Studies of a Low-Cost Particle Sensor

“…One of the disadvantage is that the response of the low-cost particle sensors varies with particle composition and size distributions, which requires repeated calibration to ensure reliable estimations of mass concentration. This disadvantage has been reported by several groups (Wang et al, 2015;Sousan et al, 2016). However, there is no sufficient study of the reasons and quantification for such variations; nor approaches proposed to enhance the accuracy.…”

“…The signal from the Sharp GP2Y is dependent on the particle composition and size distribution. Our earlier work has demonstrated that for the same mass concentration of different particle types (e.g., NaCl, sucrose, and NH 4 NO 3 ) and size distributions (e.g., 300 nm, 600 nm, and 900 nm polystyrene latex particles), the sensor signal outputs were different (Wang et al, 2015). However, the patterns of the change, together with the necessity of calibration, has not been clearly presented.…”

“…The K values of low-cost particle sensors varying with regards of aerosol composition and size distributions have been reported by several groups (Wang et al, 2015;Sousan et al, 2016). Wang et al (2015) compared the response of three sensors and an instrument (the Shinyei PPD42NS, the Samyoung DSM501A, the Sharp GP2Y, and the SidePak™) to three types of particles (NaCl particles, Sucrose particles, and NH 4 NO 3 particles) and recommended repeated calibration for different types of particles to obtain higher accuracy.…”

“…These units could be assembled for a total cost of USD 50 and used in a distributed manner. In controlled laboratory tests, low-cost particle sensors have shown high linearity and stability in comparison with commercial instruments with a known particle size and composition (Wang et al, 2015;Manikonda et al, 2016;Sousan et al, 2016Sousan et al, , 2017Zikova et al, 2017). Several studies in the literature have reported the combination of low-cost particle sensors with "smart" home devices (e.g., temperature, humidity, carbon monoxide sensors, cameras) to provide more comfortable and energy-efficient homes and workplaces (Ivanov et al, 2002;Chung and Oh, 2006;Kim et al, 2010;Bhattacharya et al, 2012;Kim et al, 2014).…”

“…Sharp GP2Y1010AU0F (Model GP2Y) was selected as the representative low-cost particle sensor due to its high linearity and long-time operational stability in comparison with reference instruments as established in a former study (Wang et al, 2015). To accomplish this, first, experimental studies for calibration were conducted in a chamber with known aerosols.…”