Measuring Air Quality for Advocacy in Africa (MA3): Feasibility and Practicality of Longitudinal Ambient PM2.5 Measurement Using Low-Cost Sensors.

Babatunde I Awokola,Gabriel Okello,Annette Erhart,Sean Semple,Christopher P Jewell,Kevin J Mortimer

doi:10.3390/ijerph17197243

Abstract

Ambient air pollution in urban cities in sub-Saharan Africa (SSA) is an important public health problem with models and limited monitoring data indicating high concentrations of pollutants such as fine particulate matter (PM2.5). On most global air quality index maps, however, information about ambient pollution from SSA is scarce. We evaluated the feasibility and practicality of longitudinal measurements of ambient PM2.5 using low-cost air quality sensors (Purple Air-II-SD) across thirteen locations in seven countries in SSA. Devices were used to gather data over a 30-day period with the aim of assessing the efficiency of its data recovery rate and identifying challenges experienced by users in each location. The median data recovery rate was 94% (range: 72% to 100%). The mean 24 h concentration measured across all sites was 38 µg/m3 with the highest PM2.5 period average concentration of 91 µg/m3 measured in Kampala, Uganda and lowest concentrations of 15 µg/m3 measured in Faraja, The Gambia. Kampala in Uganda and Nnewi in Nigeria recorded the longest periods with concentrations >250 µg/m3. Power outages, SD memory card issues, internet connectivity problems and device safety concerns were important challenges experienced when using Purple Air-II-SD sensors. Despite some operational challenges, this study demonstrated that it is reasonably practicable and feasible to establish a network of low-cost devices to provide data on local PM2.5 concentrations in SSA countries. Such data are crucially needed to raise public, societal and policymaker awareness about air pollution across SSA.

Highlights

Exposure to ambient air pollution is increasingly recognized as a serious threat to human health [1].The Lancet commission on air pollution in 2017 suggested that approximately 92% of pollution-related deaths occur in low-and-middle-income countries (LMICs) [2]
The magnitude of the risk attributable to ambient air pollution is largely unknown in sub-Saharan Africa (SSA) and largely extrapolated from data obtained from LMICs outside SSA or from household air pollution studies in SSA
Of the seventeen clinical and basic science researchers who participated in the air quality monitoring (AQM) workshop [30], thirteen representing seven SSA countries participated and contributed data to the study (Table 1)

Summary

Introduction

Exposure to ambient air pollution is increasingly recognized as a serious threat to human health [1].The Lancet commission on air pollution in 2017 suggested that approximately 92% of pollution-related deaths occur in low-and-middle-income countries (LMICs) [2]. High-income countries (HICs) have seen major improvements in health impacts attributable to reduced ambient air pollution over recent decades These health impacts include reduced risks of premature death associated with exposure to ambient fine particle pollution [7,8], reduced risks of premature mortality [9], reduced number of people with illnesses [10,11], reduced number of emergency visits; and reduced number of lost school- and work days [9]. These recent achievements are mainly due to the increasing body of evidence on air quality in indoor and outdoor spaces and increasing public awareness and advocacy on the health impacts of air pollutants. These were supported by the development of rigorous evidence-based national and supranational public health policies, such as

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