Imperial College London
Sierra Clark

Sierra Clark

Faculty of Medicine, School of Public Health

Honorary Research Associate
 
 
 
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Contact

 

sierra.clark

 
 
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Location

 

171Norfolk PlaceSt Mary's Campus

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Summary

 

Publications

Citation

BibTex format

@article{Alli:2021:1748-9326/ac074a,
author = {Alli, AS and Clark, S and Hughes, AF and Nimo, J and Bedford-Moses, J and Baah, S and Wang, J and Vallarino, J and Agyemang, E and Barratt, B and Beddows, A and Kelly, F and Owusu, G and Baumgartner, J and Brauer, M and Ezzati, M and Agyei-Mensah, S and Arku, RE},
doi = {1748-9326/ac074a},
journal = {Environmental Research Letters},
pages = {1--12},
title = {Spatial-temporal patterns of ambient fine particulate matter (PM2.5) and black carbon (BC) pollution in Accra},
url = {http://dx.doi.org/10.1088/1748-9326/ac074a},
volume = {16},
year = {2021}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Background: Sub-Saharan Africa (SSA) is rapidly urbanizing, and ambient air pollution has emerged as a major environmental health concern in SSA cities. Yet, effective air quality management is hindered by limited data. We deployed robust, low-cost and low-power devices in a large-scale measurement campaign and characterized within-city variations in fine particulate matter (PM2.5) and black carbon (BC) pollution in Accra, Ghana. Methods: Between April 2019 and June 2020, we measured weekly gravimetric (filter-based) and minute-by-minute PM2.5 concentrations at 146 unique locations, comprising of 10 fixed (~1-year) and 136 rotating (7-day) sites covering a range of land-use and source influences. Filters were weighed for mass, and light absorbance (10−5m−1) of the filters was used as proxy for BC concentration. Year-long data at four fixed sites that were monitored in a previous study (2006-2007) were compared to assess change in PM2.5 concentrations. Results: The mean annual PM2.5 across the fixed sites ranged from 26 μg/m3 at a peri-urban site to 40 μg/m3 at commercial, business, and industrial (CBI) areas. CBI areas had the highest PM2.5 levels (mean: 37 μg/m3), followed by high-density residential neighborhoods (mean: 36 μg/m3), while peri-urban areas recorded the lowest (mean: 26 μg/m3). Both PM2.5 and BC levels were highest during the dry dusty Harmattan period (mean PM2.5: 89 μg/m3) compared to non-Harmattan season (mean PM2.5: 23 μg/m3). PM2.5 at all sites peaked at dawn and dusk, coinciding with morning and evening heavy traffic. We found about a ~50% reduction (71 vs 37 μg/m3) in mean annual PM2.5 concentrations when compared to measurements in 2006-2007 in Accra. Conclusion: Ambient PM2.5 concentrations in Accra may have plateaued at levels lower than those seen in large Asian megacities. However, levels are still 2- to 4-fold higher than the WHO guideline. Effective and equitable policies are needed to reduce pollution
AU  - Alli,AS
AU  - Clark,S
AU  - Hughes,AF
AU  - Nimo,J
AU  - Bedford-Moses,J
AU  - Baah,S
AU  - Wang,J
AU  - Vallarino,J
AU  - Agyemang,E
AU  - Barratt,B
AU  - Beddows,A
AU  - Kelly,F
AU  - Owusu,G
AU  - Baumgartner,J
AU  - Brauer,M
AU  - Ezzati,M
AU  - Agyei-Mensah,S
AU  - Arku,RE
DO  - 1748-9326/ac074a
EP  - 12
PY  - 2021///
SN  - 1748-9326
SP  - 1
TI  - Spatial-temporal patterns of ambient fine particulate matter (PM2.5) and black carbon (BC) pollution in Accra
T2  - Environmental Research Letters
UR  - http://dx.doi.org/10.1088/1748-9326/ac074a
UR  - https://iopscience.iop.org/article/10.1088/1748-9326/ac074a
UR  - http://hdl.handle.net/10044/1/89363
VL  - 16
ER  -
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