Air pollution is a major problem all over the world today probably the single biggest contributor to the problem is the motor vehicle. However, there are many other man-made sources, such as industrial factories, power stations, mining, building, and the burning of fossil fuels and wood in homes around the world. There are natural sources of air pollution too; volcanoes and forest fires produce a lot of pollutants. However, it is the increasing number and use of motor vehicles that is doing the most damage, and logically, where there are more cars, there is more pollution, that is, in the major cities of the world