Efficacy of Low-Cost Sensor Networks at Detecting Fine-Scale Variations in Particulate Matter in Urban Environments

Abstract

The negative health impacts of air pollution are well documented. Not as well-documented, however, is how particulate matter varies at the hyper-local scale, and the role that proximal sources play in influencing neighborhood-scale patterns. We examined PM2.5 variations in one airshed within Indianapolis (Indianapolis, IN, USA) by utilizing data from 25 active PurpleAir (PA) sensors involving citizen scientists who hosted all but one unit (the control), as well as one EPA monitor. PA sensors report live measurements of PM2.5 on a crowd sourced map. After calibrating the data utilizing relative humidity and testing it against a mobile air-quality unit and an EPA monitor, we analyzed PM2.5 with meteorological data, tree canopy coverage, land use, and various census variables. Greater proximal tree canopy coverage was related to lower PM2.5 concentrations, which translates to greater health benefits. A 1% increase in tree canopy at the census tract level, a boundary delineated by the US Census Bureau, results in a ~0.12 µg/m3 decrease in PM2.5, and a 1% increase in “heavy industry” results in a 0.07 µg/m3 increase in PM2.5 concentrations. Although the overall results from these 25 sites are within the annual ranges established by the EPA, they reveal substantial variations that reinforce the value of hyper-local sensing technologies as a powerful surveillance tool.

PM2.5 Potential Indoor Exposures and Outdoor Concentrations Related to Smoking Prevalence by Zip Code in Three West Coast States

“…More recent studies have found such SES variables as income, education, housing, and ethnic groups to result in increased outdoor PM concentrations [4][5][6][7][8][9][10][11]. However, even with the advent of low-cost monitors, none of these studies were able to show an effect on indoor concentrations [12][13][14][15][16]. In the present study, we aim to use one of the largest studies employing low-cost monitors to explore the effect of smoking on indoor concentrations of more than 4000 residents of three West coast states.…”

Neighborhood-Level Air Pollution Monitoring and Analysis in Massachusetts

“…A study in Texas found that counting re-suspended dust emissions as part of PM 2.5 emissions could increase concentration readings by between 50 to 75 percent [22]. A study in Indianapolis that used low cost sensors found a negative correlation between PM 2.5 and tree canopy percentage, and a positive correlation with PM 2.5 and heavy industry [23]. Temporal and meteorological associations may also play an important role in PM 2.5 levels and deserve to be better understood, as they have been found to be potentially complex and multifaceted in nature.…”

“…This is in contrast to the stationary EPA monitors. Low-cost sensors have already been used in many studies, allowing for citizen scientists to conduct research and measure small-scale air quality variations [23].…”

Aprovechamiento de las tecnologías convergentes para el monitoreo de la contaminación ambiental adoptadas por el sector empresarial

“…De igual forma, el estudio de (Heintzelman et al, 2023) logró determinar que, con el uso de dispositivos electrónicos, sensores a tiempo real conocidos como Purple Air (PA), ubicado en 25 sitios de Indianápolis, Estados Unidos, se determinó que al elevar en 1% los dispositivos PA hacia las copas de los árboles, se disminuye en un ~0,12 g/m 3 en PM2,5; mientras que al elevar la proximidad de dichos sensores a áreas de 'industria pesada', los niveles de contaminación se incrementan en 0,07 g/m 3 en PM2,5. Estos resultados refuerzan la relevancia de este tipo de sensores a tiempo real,y el uso de las tecnologías convergentes a fin de apoyar esfuerzos para la caracterización y control de contaminación.…”