WRF-Chem Performance Evaluation and Source Estimation of Simulated PM2.5 in West African Cities

West Africa is an intense emitter of both anthropogenic and natural particulate pollution, both of which have been shown to have adverse health effects on human populations. With some of the world’s largest pollutant sources, such as Saharan dust and biomass burning, coupled with rapid urbanization, exploding population growth, and extreme poverty, West African pollution is complex. Despite its nuances, particulate pollution is not well characterized throughout the region, partially due to a lack of air quality monitoring networks. The recent emergence of PM2.5 measurements provided by the Environmental Protection Agency presents a unique opportunity to increase our understanding of particulate pollution in West African cities. These observational data sets along with the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) can be used to further our understanding of the sources and processes governing particulate pollution across West African cities. As a first step, we evaluate WRF-Chem primary PM2.5 speciation in Ilorin, Nigeria and the total PM2.5 mass in seven West African cities during 2021 using the Goddard Chemistry Aerosol Radiation and Transport (GOGART) aerosol scheme coupled with Model for OZone and Related chemical Tracers (MOZART) chemistry. The differences between simulated and observed PM2.5 will be presented. Additionally, we will provide a first-order estimate of the relative importance of PM2.5 sources in each city, including sea salt, biomass burning, urban emissions, and Saharan dust.