Ambient and laboratory evaluation of a low-cost particulate matter sensor

K E Kelly; J Whitaker; A Petty; C Widmer; A Dybwad; D Sleeth; R Martin; A Butterfield

doi:10.1016/j.envpol.2016.12.039

Ambient and laboratory evaluation of a low-cost particulate matter sensor

Environ Pollut. 2017 Feb:221:491-500. doi: 10.1016/j.envpol.2016.12.039. Epub 2016 Dec 21.

Authors

K E Kelly¹, J Whitaker², A Petty³, C Widmer³, A Dybwad⁴, D Sleeth⁵, R Martin⁶, A Butterfield³

Affiliations

¹ University of Utah, Department of Chemical Engineering, 3290 MEB, 50 S. Central Campus Dr., Salt Lake City, UT, United States. Electronic address: kerry.kelly@utah.edu.
² University of Utah, Department of Electrical and Computer Engineering, 2110 MEB, 50 S. Central Campus Dr., Salt Lake City, UT, United States.
³ University of Utah, Department of Chemical Engineering, 3290 MEB, 50 S. Central Campus Dr., Salt Lake City, UT, United States.
⁴ PurpleAir, 15183 Moab Way, Draper, UT, United States.
⁵ University of Utah, Rocky Mountain Center for Occupational and Environmental Health, 391 Chipeta Way, Suite C, Salt Lake City, UT 84108, United States.
⁶ Utah State University, Department of Civil and Environmental Engineering, Utah Water Research Laboratory, 8200 Canyon Road, Logan, UT 84322, United States.

Abstract

Low-cost, light-scattering-based particulate matter (PM) sensors are becoming more widely available and are being increasingly deployed in ambient and indoor environments because of their low cost and ability to provide high spatial and temporal resolution PM information. Researchers have begun to evaluate some of these sensors under laboratory and environmental conditions. In this study, a low-cost, particulate matter sensor (Plantower PMS 1003/3003) used by a community air-quality network is evaluated in a controlled wind-tunnel environment and in the ambient environment during several winter-time, cold-pool events that are associated with high ambient levels of PM. In the wind-tunnel, the PMS sensor performance is compared to two research-grade, light-scattering instruments, and in the ambient tests, the sensor performance is compared to two federal equivalent (one tapered element oscillating microbalance and one beta attenuation monitor) and gravimetric federal reference methods (FEMs/FRMs) as well as one research-grade instrument (GRIMM). The PMS sensor response correlates well with research-grade instruments in the wind-tunnel tests, and its response is linear over the concentration range tested (200-850 μg/m³). In the ambient tests, this PM sensor correlates better with gravimetric methods than previous studies with correlation coefficients of 0.88. However additional measurements under a variety of ambient conditions are needed. Although the PMS sensor correlated as well as the research-grade instrument to the FRM/FEMs in ambient conditions, its response varies with particle properties to a much greater degree than the research-grade instrument. In addition, the PMS sensors overestimate ambient PM concentrations and begin to exhibit a non-linear response when PM_2.5 concentrations exceed 40 μg/m³. These results have important implications for communicating results from low-cost sensor networks, and they highlight the importance of using an appropriate correction factor for the target environmental conditions if the user wants to compare the results to FEM/FRMs.

Keywords: Air quality; Cold-air pool; Low-cost sensors; Particulate matter.

MeSH terms

Air Pollutants / analysis*
Environmental Monitoring / instrumentation*
Environmental Monitoring / methods
Laboratories
Particle Size
Particulate Matter / analysis*
Seasons
Wind

Substances

Air Pollutants
Particulate Matter

Grants and funding

U54 EB021973/EB/NIBIB NIH HHS/United States