The Impact of Vehicle Engine Characteristics on Vehicle Exhaust Emissions for Transport Modes in Lagos City

ABSTRACTThe study delves into how vehicle engine characteristics impact the release of air pollutants from various vehicle fleets in Lagos, Nigeria. It involved the direct measurement of emissions from the exhaust pipes of 88 vehicles using gas analyzers. The vehicle fleets encompassed motorcycles, tricycles, private cars, minibuses, large buses, and trucks. A statistical analysis was conducted on carbon monoxide (CO) and nitrogen oxide (NOx) emissions to develop a model equation based on vehicle type, engine type, vehicle age, and purchase status. Results indicate that personal cars and minibuses predominantly emit CO from gasoline engines, whereas large buses and trucks significantly contribute to NOx emissions from diesel engines. Further scrutiny revealed that 66% of the vehicles examined were over 10 years old, resulting in a 65% increase in emission levels. Approximately 60% of gasoline and 75% of diesel vehicles exceeded the permissible emission limits, leading to air quality deterioration and heightened health risks. The study underscores the risks associated with ageing vehicles and different engine types, emphasizing the imperative for a gradual transition to low-carbon or electric vehicles in developing African cities to combat air pollution and mitigate health hazards.