A review on ambient and indoor air pollution status in Africa

Abstract In spite of the global outcry for urgent action against air pollution, most African countries lack functional air quality monitoring stations and data there from; making air quality management difficult. Therefore, stand-alone studies are reviewed to provide information on air pollutant levels, sources, spatial and seasonal variation across the continent. Air quality studies are limited in Africa. Available data show that vehicular traffics, industries, wildfire and biomass burning are significant sources of PM, CO, NO2, SO2 and VOCs in the continent. Sahara Desert is an important source of PM in the region especially during harmattan periods. The air levels of pollutants exhibit seasonality and is inversely impacted by increased precipitation rate and wind speed. Exceedances of WHO AQG are common in both season. The reported annual and 24-h mean concentrations of ambient PM are respectively lower than the relevant WHO AQG in only 10 and 13% for PM2.5, and 0% and 12% for PM10. Only a third of the towns have ambient CO concentrations below the 24-h WHO (7 mg/m³) AQG. Benzene levels at nearly all (96%) sites are a factor 2–920 times larger than 0.17 μg/m³ associated with an excess lifetime risk 1/1000 000. The mean concentrations of indoor PM, CO, NO2 and SO2 exceed the relevant WHO AQG and much more in firewood-fueled poorly-ventilated kitchens in the rural areas, implying a potentially high exposure to women and children in Africa.