Air pollution causes degradation of air quality. It is a widely acknowledged fact that air pollution has adverse effects on human health and on both natural and built environment. Today, air pollution is recognised as being the single​ largest environmental health risk in the European Union and has been classified by the International Agency for Research on Cancer of the WHO, as a leading environmental cause of cancer deaths​.

Some atmospheric emissions are capable of exerting their adverse effect on both human health and the environment directly, while other emissions to the atmosphere are transformed into pollutants through complex atmospheric reactions.

In addition to the affects​ of direct inhalation, air pollutants can make it into the human body through the food chain or water, once they deposit and accumulate in the environment.