Assessing Vehicular Particulate Matter Emissions, Exposure and Health Risks in Thiès, Senegal

Abstract

African cities are growing at a fast pace. The demographic growth rate of about 2% per annum is a key driving factor of the accelerated urbanization. In developing cities, proliferation of small businesses is seen on major roads, where imported vehicles with old and inefficient internal combustion engines move and emit large quantities of pollutants. In the center of Thiès (Senegal), a route of about 10 km long was considered to evaluate concentrations of suspended particles. Between 16th – 31st of May 2024, a portable optical particle counter, a Particle Plus 8301-AQM1 was used to measure particles concentrations at 10 urban sites, and health risk assessment was performed. Average PM2.5 concentration exceeded the threshold value (15 µg.m-3) by 2 up to 5 folds, and that of PM10 (45 µg.m-3), from 5 up to 16 folds. Particle size distribution showed predominance of coarse particles (86%) over fine particles (14%). Hazard quotient (HQ) varied between 1.7 – 4.0 for PM2.5 and in the range 4.2 – 12.4 for PM10 showing that those working or living on or near roads could develop non-carcinogenic diseases. Life Cancer Risk (LCR) was above 10-4, meaning there is an existing probability that those exposed to the recorded level of PM2.5 could develop cancer diseases. The study concludes that governments in African developing nations along with local authorities should inform city dwellers and develop policies that include smart transportation, electrification, pavement of roads and strict control of fuels quality to tackle air pollution in urban areas.