Long-term trend and seasonality of PM$$_{2.5}$$ components over sub-Saharan West Africa sub-region and its implications on selected meteorological variables

Aerosols are an essential component of the atmosphere and have prominent impacts on climatic conditions on both synoptic and regional scales. Their climate impacts are influenced by their concentrations, nature, type, and composition. In the sub-Saharan West African (SSWA) subregion, the West African monsoon (WAM) play prominent roles in the variability of these properties, and hence the trend and intensity of their impacts. Considering the strategic position of the subregion, an in-depth and adequate knowledge of the variability and evolution of atmospheric aerosol and its components would engender accurate and robust research on the contribution of these aerosols to climate conditions and variability of atmospheric variables. In the SSWA region, despite its well-established health and climatic impact, there is a paucity of accurate information on the diurnal, long-term and seasonal variation of PM $$_{2.5}$$ , a prominent component of atmospheric aerosols. This study, which examines the variation of PM $$_{2.5}$$ and its components over a 30-year period in SSWA, establishes the pronounced impacts of seasonality on the loading and nature of the pollutant and its components during the investigated period. In particular, SO $$_{4}$$ and sea salt levels have increased significantly around the coastal areas of the Gulf of Guinea and the Sahara Desert, respectively, especially during the onset (MAM) and peak (JJA) of WAM. During the 30-year period, the concentration of carbon content (BC and OC) of atmospheric aerosol has increased by 30–70%, especially between February and October, months of intense burning of biomass in Central and Southern Africa. These findings give some insight into changes in climatic conditions and the variability of atmospheric variables, both of which are of great importance to pollution modeling, climate modelers, and policy makers.