Environmental Variation of PM 2.5 Concentrations and Their Relationship to Meteorological Parameters in Southern Ghana

Evidence shows that cities in sub-Saharan African (SSA) countries are experiencing high levels of air pollution with significant consequences for public health. This burden could become worse unless data-driven mitigation policies are implemented to improve the situation. The purpose of the study was to analyze the impact of meteorological events on seasonal variations in ambient PM _2.5 concentrations in the Greater Accra Metropolitan Area. This study involved the secondary analysis of PM _2.5 concentrations and meteorological data from 2019 to 2023 to provide comprehensive information on air pollution variation along major roads in the rapidly growing SSA city of Accra. The results obtained indicate that the median concentrations of PM _2.5 at Mallam Market in 2022 peaked at 300µg/m³ during the dry season relative to the wet season. The First Light season was an exception, with median concentrations higher in the rainy season (200µg/m³). Compared to the dry season, the wet season was associated with significantly higher PM _2.5 levels from 2021 to 2023 at all locations. PM _2.5 levels reduced by 19–24% for every 1 ^o C increase in temperature (IRR:0.76–0.81) and 26–38% for every 1mm of rainfall (IRR: 0.62–0.74). However, PM _2.5 levels increased 10–16% for every 1% rise in humidity (IRR: 1.10–1.16). These findings indicate that humidity was a significant factor influencing the high PM _2.5 concentrations during dry and wet seasons. This highlights the urgent need for continuous air quality and weather monitoring, alongside stricter compliance with regulations on vehicular emissions and road construction.Clinical trial number: not applicable