Impact of air pollution on mortality: Geo-epidemiological study in French-speaking Africa

Abstract

According to the World Health Organization, air pollution is responsible for 90 % of deaths in Africa. However, limited data on exposure to air pollution is available, and studies are rare, particularly in French-speaking Africa. This study aims to investigate the impact of air pollution on mortality in 12 French-speaking African countries (Algeria, Burkina Faso, Burundi, Cameroon, Guinea, Ivory Coast, Madagascar, Mali, Morocco, Democratic Republic of Congo, Senegal, Tunisia). Using data from the Institute for Health Metrics and Evaluation (IHME), annual concentrations of the PM_2.5 pollutant from different cities were integrated into a spatial interpolation model (IDW) at the scale of each country. The interpolation was validated using cross-validation models. For each of the considered cardiorespiratory diseases (LRI, stroke, COPD, IHD), the attributable mortality fraction was estimated using literature data and population exposure calculated using demographic data from each country. Large variations in ambient PM_2.5 concentration between the 12 countries are observed, with concentrations ranging from 1.76 μg/m³ in Morocco to 64.99 μg/m³ in Cameroon. Concentrations are higher in West Africa than in Central or North Africa. In 2019, 136 457 deaths attributable to air pollution were recorded in the 12 countries: 40.8 % from ischemic heart disease, 38.5 % from stroke, 13.2 % from lower respiratory infections and 7.5 % from chronic obstructive pulmonary disease. Our model allowed us to obtain a spatial distribution and the number of deaths related to air pollution. However, the estimation of the health impact from air pollution could be improved by more systematic and comprehensive local exposure assessments from a robust air quality monitoring system.

Keywords: Air pollution; Cardiorespiratory diseases; PM2.5; Spatial interpolation.

Fig. 1

Diagram of the method used The general framework is described on Fig. 1.

Fig. 2

Map of Africa. Shaded countries are the French-speaking country we considered.

Fig. 3

Map of PM_2.5concentration distribution (in μg/m³) in 12 Francophone African countries a.Algeria, b.Burkina Faso, c.Burundi, d.Cameroon, e.Ivory Cost, f.Guinea, g.Madagascar, h.Mali, i.Morocco, j.Democratique Republic of the Congo, k.Senegal, l.Tunisia.