Emissions and Health
Air pollution is one of the worst environmental hazards in urban areas of developing countries and transport is one of its main sources. Typically, vehicles constitute the largest source of pollutants as compared to other sectors like industries, power generation, heating (World Bank, 2006). Vehicles, which use fossil fuels, emit oxides of nitrogen, carbon monoxide, hydrocarbon and particulate matter like PM10 and PM2.5. Sizeable quantities of chemicals like aldehyde and lead are also emitted by vehicles. Besides this, vehicle emissions are known to contribute significantly to the production of aerosols (a suspension of fine solid or liquid droplets in a gas), which are formed when emissions from vehicles combine with the air and create a haze or fog. Sulfates are areosols produced from the combustion of fossil fuels. The pollutants emitted and their quantity depend largely on the quality of fuel used, vehicle technology and its maintenance.