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Air pollution

What is air pollution?

An air pollutant is anything  in the air that could harm people’s health. There are many pollutants in the air.

Some are more harmful than others. Particulate matter, nitrogen dioxide and ozone are particularly damaging types of air pollution.

You can also read about indoor air pollution.

Levels of air pollution vary across the UK. Higher levels are generally found in most UK towns and cities. This is where sources of pollution, such as road traffic, are more concentrated. In the country, farming can also be a source of air pollution.

The amount of air pollution can also change depending on the weather and the season. For example, it’s harder for pollution to disperse during still, sunny weather in summer and still, foggy weather in winter. This means pollution becomes more concentrated causing a high pollution episode. These episodes often affect towns and cities, but they can also affect areas of the countryside as the wind can blow pollution across the country.

See an up-to-date pollution forecast for your area on DEFRA's UK air page.

Car exhaust causing air pollution

Next: Where does air pollution come from? >

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Download our air pollution information (150KB, PDF)

Last medically reviewed: April 2020. Due for review: April 2023

This information uses the best available medical evidence and was produced with the support of people living with lung conditions. Find out how we produce our information. If you’d like to see our references get in touch.