You can often see it coming out of chimneys. Carbon monoxide is a pollutant that is mainly produced by cars . It has no colour or smell but can be very poisonous. Nitrogen oxides are emitted from cars and power stations . Very high amounts can be recorded in cities during rush-hour traffic.
Sulphur dioxide is a colourless gas that is mainly given off from power stations.
It combines with water in the air to produce acid rain . Particulates are small bits of solid or liquid matter, for example soot, dust, fumes and aerosols carried in the air. They are produced by factories, cars and coal burning in some homes. Ozone, a form of oxygen, is more commonly associated with the ozone layer, which protects life on Earth from the Sun's harmful rays. Near the ground however, it is a harmful pollutant made in the air when other pollutants mix together in sunlight.