Sources of air pollution

Although air pollution comes from different sources, most is caused by road traffic. This is detailed further in the pages on our Clean Air Zone web pages.

The other main sources of man-made air pollution are industrial emissions, bonfires and domestic solid fuel burning.

All combustion (burning) processes in air produce oxides of nitrogen (NOX), but we mainly measure levels of nitrogen dioxide (NO2). Road transport is the main source, followed by the electricity supply industry and other industrial and commercial activities.

Particulate matter is made up of a range of materials from both human-made and natural sources. In the UK the biggest human-made sources are the burning of fuels and transport. Road transport gives rise to particles from engine emissions, tyre and brake wear and other non-exhaust emissions. The increase in domestic wood burning for space heating, or as a lifestyle trend, gives rise to emissions of fine particulate matter both within the household and to the locality – this is a growing cause for concern.

In the UK, sulphur dioxide (SO2) emissions mostly comes from burning fuels containing sulphur, such as coal and heavy oils used in power stations and refineries.