Quantifying the Exposure of Unhealthy to Hazardous PM2.5 and PM10 Concentrations to Adult and Children Populations in Senegal during Four Significant Dust Events

Air pollution is responsible for one in nine deaths globally and may get worse over time with the growth of Megacities population. Saharan dust aerosols pose as a natural hazard and can significantly reduce air quality. We examine four multi-day dust events in Senegal during December 2016, 2017, February and March 2019. Because of limited surface measurements across Senegal and Africa in general, we use the Weather Research and Forecasting (WRF) model to predict PM_2.5 and PM₁₀ concentrations across Senegal during the four dust events. The simulated values are put into a GIS framework, and we use 2015 estimated population to determine the exposure to the total population and to children under age 5. The most severe of the four storms occurred in December 2017, however the February 2019 dust event occurred during the Presidential elections in Senegal resulting in an estimated 4 million voters being exposed to unhealthy air quality. We find that the dust storm from the period of 19-30 December 2017 exposed large segments of the population to unhealthy PM₁₀ (> 255 μg-m^-3) and PM_2.5 (> 55.5 μg-m^-3) concentrations. During this period, 86% of the total population and 84% of children under 5 were exposed to unhealthy PM₁₀ dust concentrations for more than seven (7) days. Further, 100% of the total population and children under 5 were exposed to unhealthy PM_2.5 dust concentrations for more than seven (7) days. We present simulated spatial patterns of exposure in the 14 administrative districts of Senegal for the four storms in our presentation.