Dumpsite Emissions in Southwestern Nigeria: Assessing the Relationships Between Atmospheric Conditions, Ghgs and Air Pollutant

Seasonally, this study investigates the relationship between atmospheric parameters (temperature, relative humidity and oxygen) levels of greenhouse gases (GHGs: CH4 and CO2), criteria air pollutants (CAPs: PM2.5, PM10, O3, CO, SO2, and NO2), and other gaseous pollutants (HCHO, NO, NH3, and VOC) at selected dumpsites in metropolitan cities of southwestern Nigeria. The city’s dumping sites (State) were Olusosun Ojota (Lagos), Saje Abeokuta (Ogun), Agodi Ibadan (Oyo), Akure (Ondo), Ado Ekiti (Ekiti), and Osogbo (Osun). The portable meteorological station (Kestrel model: 3000 NV, Boothwyn, USA) measured atmospheric parameters, while the Multimeter BOSEAN T Z01 and AEROQUAL 500 series air quality meter measured the pollutants’ levels. Utilizing correlation heat maps, the analysis revealed significant associations between meteorological parameters and pollutant emissions. During the dry season, methane (CH₄) and carbon dioxide (CO₂) exhibited strong positive correlations with temperature (r = 0.99 and 0.65, respectively), driven by microbial activity under anaerobic conditions. Ammonia (NH₃) and nitric oxide (NO) showed close linkages with CH₄ and CO₂ (r = 0.80–0.88), suggesting shared nitrogen transformation pathways. In the wet season, temperature similarly influenced CH₄ (r = 0.99) and CO₂ (r = 0.81), while combustion related pollutants like nitrogen dioxide (NO₂) and sulfur dioxide (SO₂) displayed near perfect correlations (r = 1.00). Ozone (O₃) exhibited strong inverse relationships with precursors (CO, NO) due to photochemical dynamics. Findings show temperature, microbial processes, and combustion drive pollutant emissions, stressing the need for region-specific waste strategies to mitigate air quality and climate impacts in tropical urban areas.