Understanding Aerosol Interactions in the Atmosphere: A Case Study of Kumasi, Ghana

Abstract

Atmospheric aerosols influence regional climate systems; however, their effects remain underexplored in West African cities. This study assessed aerosol interaction in the atmosphere of Kumasi, Ghana, using satellite-derived datasets from MERRA-2, GEOS-CF, and ERA5 from September to December 2022. The study examined temporal variations in aerosol concentration, spatial variability across urban, peri-urban, and rural sites, and relationships between aerosols, SSR, and temperature. A quantitative observational research design was adopted using data from four monitoring locations: Fumesua Community, Fumesua Farm, Sokwai Community, and Sokwai Farm. Quality control procedures included modified z-score outlier screening and physical consistency checks, while descriptive statistics, ANOVA, correlation analysis, and polynomial regression were applied. Aerosol concentration increased sharply from 5 − 25 𝜇𝑔/𝑚³ in September to 80 − 125 𝜇𝑔/𝑚³ in December, exceeding WHO thresholds during the Harmattan season. Spatial variations were statistically insignificant (𝐹 = 0.7027, 𝑝 = 0.6699), indicating the dominance of regional atmospheric processes over local emissions. Aerosols exhibited an inverse relationship with SSR (R² = 0.59 − 0.60) and a bi-phasic association with temperature (R² = 0.78), with warming at low-to-moderate concentrations and cooling at high concentrations (> 80 𝜇𝑔/𝑚³). SSR and temperature showed consistently strong positive correlations (R² = 0.82 −0.84). The study concludes that aerosol loading significantly alters climate variables in Kumasi and highlights the need for coordinated mitigation measures. Limitations include the four month timeframe and absence of ground-based validation. The research offers baseline evidence to support national air quality and climate adaptation planning.