Concentrations ofsix pollutants reduced between 2007 and 2008. Between 1998 and 2008 concentrations of eight pollutants have reduced.
The substances that cause air pollution are called pollutants. If they are pumped into our atmosphere and directly pollute the air are called primary pollutants. Carbon monoxide from car exhausts, sulphur dioxide from the combustion of coal is example for primary pollutants. If primary pollutants in the atmosphere undergo chemical reaction, and further cause pollution, they are secondary pollutants. Photochemical smog is an example for secondary pollutant.
Air pollutants mainly occur as a result of gaseous discharges from industry and motor vehicles. There are also natural sources such as wind-blown dust and smoke from fires. With increasing urbanisation and industrialisation, more pollution has been added to the air by industrial, commercial and domestic sources. When these concentrated gases like Co, Co2, So2, No2, Ozone, and Pm10 exceed safe limits, we have a pollution problem.
Air pollution, particularly in cities, is not a new problem. Back in the middle ages the use of coal in cities such as London was beginning to escalate. In UK the industrial revolution during the 18th and 19th centuries was based on the use of coal. ...