Persistent urban PM_2.5 pollution in Accra, Ghana: spatiotemporal patterns, meteorological and anthropogenic drivers, and associated health risks

Fine particulate matter (PM₂.₅) pollution poses a serious environmental and public health threat in rapidly urbanizing regions in Africa, yet high-quality, long-term measurements remain rare across sub-Saharan Africa. This two-year study (2021–2022) delivers one of the few spatiotemporally resolved PM₂.₅ datasets in Ghana, generated using USEPA Federal Reference Method (FRM) gravimetric samplers. Over 300 samples were collected at three contrasting sites in Accra, Ghana: Adabraka (AD), adjacent to the Agbogbloshie e-waste burning area; Dansoman (DA), a mixed residential–commercial neighborhood; and Legon (UG), a suburban reference site. Mean 24-h concentrations exceeded WHO guidelines by a factor of about 3–4 at all sites, with AD recording the highest levels (60.76 µg/m³ in 2021; 60.54 µg/m³ in 2022) due to persistent, localized emissions. While interannual variability was minimal, spatial contrasts were pronounced, reflecting stable and dominant anthropogenic sources. Principal component analysis identified temperature (positive correlation) and relative humidity (negative correlation) as key meteorological drivers of PM₂.₅ variability. Health risk assessment indicated hazard quotients (HQ) above 1 for both adults and children, with markedly higher risks in children due to physiological and behavioral factors. Beyond its local implications, this dataset fills a critical regional gap, providing a benchmark for validating satellite-based estimates and regional chemical transport models, and informing targeted interventions in resource-limited regions.