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Understanding the Sources of Urban Air Quality Using Low-Cost Air Quality Sensors
LAURA YANG, David Hagan, Jean Rivera-Rios, Zahra Shivji, Eben Cross, Chris Peng, Jennifer Kaiser, Nga Lee Ng, Georgia Institute of Technology
Abstract Number: 321
Working Group: Instrumentation and Methods
Abstract
Advances in low-cost sensor (LCS) technologies for measuring air quality have provided the public with readily accessible information on their exposure to detrimental air pollutants. Previously, LCS were primarily used to measure air pollution levels, but more recent literature suggests that source apportionment analysis of pollutants is possible. The primary objective of this study is to investigate the sources of urban air pollutants using LCS. The second objective is to determine the capabilities of the different sensors in measuring particulate matter (PM) in an urban area. From November to December 2020, we deployed QuantAQ LCS that measure both gases (CO, NO, NO2, and O3) and PM along with Purple Air LCS and various research-grade instruments (Aerosol Chemical Speciation Monitor (ACSM), Scanning Mobility Particle Sizer (SMPS), O3 and NOx monitors) in Atlanta, GA. The unsupervised algorithm non-negative matrix factorization (NMF) was then employed to resolve factors that describe the Atlanta air quality. We compare the capability of optical particle sensors and nephelometers and the performance of QuantAQ LCS and Purple Air LCS in measuring PM. We identified three factors (CO-dominated, O3-dominated, and particle factor) with different temporal trends and properties. The CO-dominated factor correlates well with combustion-related organic aerosol (OA) factors (hydrocarbon-like, biomass burning, and cooking OA) resolved from positive matrix factorization (PMF) analysis of ACSM data. Moreover, the particle factor correlates with inorganics measured from the ACSM. Results from this study exhibit that LCS not only can be used to provide basic mass concentration information but also can be used for in-depth source apportionment studies even in an urban setting with complex pollution mixtures and relatively low aerosol loadings.