Determination of Satellite-Derived PM2.5 for Kampala District, Uganda
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Date
2022
Journal Title
Journal ISSN
Volume Title
Publisher
Geomatics
Abstract
Ground monitoring stations are widely used to monitor particulate matter (PM2.5). However,
they are expensive to maintain and provide information localized to the stations, and hence are
limited for large-scale use. Analysis of in situ PM2.5 shows that it varies spatially and temporally with
distinct seasonal differences. This study, therefore, explored the use of satellite images (Sentinel-2
and Landsat-8) for determining the spatial and temporal variations in PM2.5 for Kampala District in
Uganda. Firstly, satellite-derived aerosol optical depth (AOD) was computed using the Code for High
Resolution Satellite mapping of optical Thickness and aNgstrom Exponent algorithm (CHRISTINE
code). The derived AOD was then characterised with reference to meteorological factors and then
correlated with in situ PM2.5 to determine satellite-derived PM2.5 using geographically weighted
regression. In the results, correlating in situ PM2.5 and AOD revealed that the relationship is highly
variable over time and thus needs to be modelled for each satellite’s overpass time, rather than having
a generic model fitting, say, a season. The satellite-derived PM2.5 showed good model performance
with coefficient of correlation (R2) values from 0.69 to 0.89. Furthermore, Sentinel-2 data produced
better predictions, signifying that increasing the spatial resolution can improve satellite-derived
PM2.5 estimations.
Description
Keywords
Aerosol optical depth (AOD), Particulate matter (PM2.5), Remote sensing
Citation
Atuhaire, C.; Gidudu, A.; Bainomugisha, E.; Mazimwe, A. Determination of Satellite-Derived PM2.5 for Kampala District, Uganda. Geomatics 2022, 2, 125–143. https:// doi.org/10.3390/geomatics2010008