Radon is a naturally occurring radioactive gas found in the air we breathe. We have always received doses of radiation from it and always will. Radon comes from uranium, which is present to a small extent in all soils and rocks. It seeps out of the ground and can collect in enclosed spaces such as workplaces and homes.

Because some ground types allow air to move more freely than others do, and the amount of uranium in the ground varies from place to place, radon levels are higher in some parts of the country than other, such as Northamptonshire.


Radon decays to form tiny radioactive particles, which can be breathed in. These particles contain radiation, which can cause lung cancer, which may take years to develop. In addition, smoking and exposure to radon are known to work together in greatly increasing the risk of developing lung cancer.

Generally, Radon is only a concern in a building or confined space where there is less ventilation than in the open air. The construction of a building in an important factor because radon seeps up from the ground and is drawn into buildings through cracks in the floors and any gaps (e.g. pipes, cables, drains, etc).

Maps and guidance

Public Health England provides information, advice and testing kits for monitoring Radon.

The darker the colour on radon maps, the greater the chance of a high Radon level in a building. However not all buildings, even in the darkest areas, have high levels.

Last updated 03 May 2023