A low-cost monitor for simultaneous measurement of fine particulate matter and aerosol optical depth – Part 1: Specifications and testing

Eric A Wendt,Daniel D Miller-Lionberg,Jeffrey R Pierce,Jessica Tryner,Azer P Yalin,Casey W Quinn,Shantanu Jathar,Christian L'Orange,Bonne Ford,John Volckens

doi:10.5194/amt-12-5431-2019

Abstract

Abstract. Globally, fine particulate matter (PM2.5) air pollution is a leading contributor to death, disease, and environmental degradation. Satellite-based measurements of aerosol optical depth (AOD) are used to estimate PM2.5 concentrations across the world, but the relationship between satellite-estimated AOD and ground-level PM2.5 is uncertain. Sun photometers measure AOD from the Earth's surface and are often used to improve satellite data; however, reference-grade photometers and PM2.5 monitors are expensive and rarely co-located. This work presents the development and validation of the aerosol mass and optical depth (AMOD) sampler, an inexpensive and compact device that simultaneously measures PM2.5 mass and AOD. The AMOD utilizes a low-cost light-scattering sensor in combination with a gravimetric filter measurement to quantify ground-level PM2.5. Aerosol optical depth is measured using optically filtered photodiodes at four discrete wavelengths. Field validation studies revealed agreement within 10 % for AOD values measured between co-located AMOD and AErosol RObotics NETwork (AERONET) monitors and for PM2.5 mass measured between co-located AMOD and EPA Federal Equivalent Method (FEM) monitors. These results demonstrate that the AMOD can quantify AOD and PM2.5 accurately at a fraction of the cost of existing reference monitors.

Highlights

Fine particulate matter air pollution (PM2.5) is a leading contributor to premature death and disease globally (Brauer et al, 2016; Forouzanfar et al, 2016)
The AMOD design was based on a low-cost gravimetric sampler known as the ultrasonic personal aerosol sampler (UPAS), which was developed through prior work (Volckens et al, 2017)
Close agreement was observed between the AMOD and AErosol RObotics NETwork (AERONET) monitors for aerosol optical depth (AOD)

Summary

Introduction

Fine particulate matter air pollution (PM2.5) is a leading contributor to premature death and disease globally (Brauer et al, 2016; Forouzanfar et al, 2016). Satellite observations have been used to estimate PM2.5 levels at the Earth’s surface. These estimates have facilitated global estimates of air pollution’s impact on public health, especially in remote and resource-limited environments (Brauer et al, 2016). Satellite-based observations provide an estimate of aerosol optical depth (AOD), a dimensionless measure of light extinction in the atmospheric column. Satellite-derived AOD retrievals are used to estimate PM2.5 concentrations at the Earth’s surface (van Donkelaar et al, 2006, 2010; Lv et al, 2016).

Objectives

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Conclusion