Search Icon
HomeClean Air informationForecastsAboutClean Air calculator

Where does air pollution come from?



What's polluting the air? Air pollution comes from lots of different sources and can be found in both rural and urban areas.


Where does outdoor air pollution come from?

Road transport, including cars and delivery vehicles, is the main source of Nitrogen Dioxide.


Household burning, such as the use of wood stoves and open fires, is the biggest contributor to  Particulate Matter pollution. 


The biggest source of Sulphur Dioxide is from energy generation and industry, and the largest source of VOCs is the solvents in household products.


Farming is the main source of ammonia and pollutants are also created from other sources of transport such as planes, trains and boats. 

An illustration showing where air pollution can come from

This image shows the various sources of outdoor air pollution

Where does indoor air pollution come from?

Air pollution isn’t just about the outdoor world. There are many sources of indoor air pollution that can harm health. Studies have found that as much as 90% of the day is spent indoors so it is important to consider how to create clean air at home. Children for example spend most of their time indoors, with just 68 minutes spent outside on an average day. Too many of our homes and schools are damp and poorly ventilated – this may be damaging the health of children.

Sources of indoor air pollution:


Cooking, smoking and burning solid fuels (e.g. wood, coal,  and charcoal), which generate particulate matter (PM), as well as other pollutants such as nitrogen dioxide (NO2) and carbon monoxide (CO).


Domestic appliances (boilers, heaters, fires, stoves and ovens), which burn carbon containing fuels (coal, coke, gas, kerosene/paraffin and wood) that can emit carbon monoxide (CO) as well as other pollutants if not properly maintained or vented.


New furniture and furnishings, which can be sources of pollutants such as volatile organic compounds (VOCs) or formaldehyde.


Building materials (including fittings and flooring), which can emit volatile organic compounds.


Consumer products, including household (e.g. paints, aerosols, cleaning products and candles) and personal care products (cosmetics, hair sprays), which can emit volatile organic compounds and semi-volatile organic compounds (SVOCs).


Flame retardants, pesticides and disinfectants, which can release semi-volatile organic compounds.


Biological sources, including mould, house dust mites, bacteria, pests and pet dander which can also lead to poorer indoor air quality.


Naturally occurring pollutants can also lead to poor indoor air quality. For example, radon is a colourless, odourless radioactive gas that is formed by the decay of elements that occur naturally in rocks and soils, and can also be found in certain building materials and water. If you're concerned about Radon, you can get more information and advice at UKradon.


Back to top



If you would like to find out more about where all the stats, facts and figures have come from, see our references page