Analysis of ambient PM2.5 sources in a fish-smoking settlement and a major highway crossroads in the Central Region, Ghana

Abstract

Fine particulate (PM2.5) is a potentially toxic entity with diverse sources. This study measured ambient PM2.5 concentrations and identified the major sources at the Winneba Highway Intersection (WHI) and the Apam Fish-smoking Community (AFC). Particulate samples were collected using a Gent sampler fitted with a Gast pump and a stacked filter unit for particle deposition onto nuclepore filters. Sampling was conducted thrice weekly from July 2022 to June 2023 for 24-h periods. Elemental composition was determined using an Ag-anode X-ray fluorescence spectrometer and a smoke stain reflectometer. Source apportionment was performed using Positive Matrix Factorisation (PMF), while air quality was evaluated using the Air Quality Index (AQI). Results showed clear temporal variability in PM2.5 concentrations across seasons. AQI ratings indicated moderate air quality during both dry and wet periods, implying potential health risks for sensitive populations. PMF analysis identified five major contributing sources at each site. At WHI, PM2.5 was primarily attributed to soil and resuspended road dust (33.55%), sea salt and resuspended dust (28.75%), combustion emissions (14.06%), minor industrial activities (12.87%), and long-range transport (10.77%). At AFC, the dominant sources were soil dust (26.33%), sea salt (24.03%), resuspended dust (21.25%), fossil fuel combustion (14.76%), and biomass burning (13.67%). Combined anthropogenic emissions accounted for 26.93% of PM2.5 at WHI and 28.4% at AFC. These findings highlight the significant contribution of both natural and human activities to PM2.5 pollution in coastal Ghanaian communities. Effective mitigation strategies should prioritize cleaner fuel use and environmentally sustainable transportation systems.