Meteorological Influences on Solid Waste Decomposition and Pollution Dispersion: A Case Study of Ado-Ekiti, Ekiti State, Nigeria

Open dumpsites remain the predominant municipal solid waste disposal method in many tropical secondary cities, yet their emissions are often treated as temporally uniform in environmental assessments. This study evaluates the influence of seasonal meteorological variability on waste decomposition and pollutant dispersion in selected open dumpsites in Ado-Ekiti, Nigeria. 12-month monitoring program integrated field meteorological measurements, waste characterization, methane flux estimation, particulate matter monitoring, Gaussian plume dispersion modelling, and multivariate statistical analysis. Results reveal clear seasonal contrasts. Wet-season conditions increased waste moisture content (up to 61%) and accelerated decomposition rates (k = 0.082 month⁻¹), resulting in significantly higher methane emissions. Conversely, dry-season Harmattan winds elevated particulate matter concentrations (PM₁₀ up to 118 µg/m³) and enhanced downwind dispersion under stable atmospheric conditions. Meteorological variables collectively explained 69–74% of emission variability (p < 0.05), confirming strong climatic control over both gas generation and pollutant transport. The findings demonstrate that tropical open dumpsites operate as seasonally dynamic emission systems. Effective mitigation therefore requires climate-responsive landfill engineering, seasonal monitoring frameworks, wind-informed zoning, and improved greenhouse gas inventory methodologies for tropical urban environments.