Radon gas

Radon gas emanates naturally from rocks and soils in the ground, mixes with air and rises to the surface where it is quickly diluted in the atmosphere. Concentrations in the open air are very low. However, radon that enters enclosed spaces, such as buildings, can reach relatively high concentrations in some circumstances.

  • Radon is a naturally occurring radioactive gas.
  • It comes from the minute amounts of uranium that occur naturally in most rocks and soils.
  • It has no odour, taste or colour (at standard temperature and pressure).
  • It can only be detected by using specialist equipment.
  • Radon is present throughout the country and in Thanet at levels that pose a low risk.

Radon gas is generated by the breakdown of radioactive radium, which in turn is the decay product of uranium, found in the earth’s crust [1]. It is present in small quantities in most soils and rocks, although the amount varies from place to place. It is particularly prevalent in granite and limestone areas, but not exclusively so. Radon levels vary not only between different parts of the country, but even between neighbouring buildings. Most homes even in the higher radon affected areas will not have a radon problem.

[1] N.N. Greenwood and A. Earnshaw (1994) ‘Chemistry of the Elements’, Oxford: Pergamon Press, 1454-55.




Public Health England (formerly the Health Protection Agency) measures radon levels in Becquerel per cubic metres of air (Bq m-3) and have advised the government that a reading of 200 Bq m-3 in homes should be considered the ‘Action Level’. This is the level at which action should be taken to reduce the radon concentration.


Public Health England and the British Geological Survey have jointly produced new information on radon Affected Areas in England and Wales. A new atlas was published on 12 Nov 2007 giving an overview of ‘Radon Affected Areas’ by km2 of the national grid. The atlas is indicative rather than definitive (ie. it refers to the maximum percentage band that exists within each km2 grid). This material replaces the existing Radon Atlas of England and Wales. These maps may be viewed at http://www.ukradon.org/


According to the new indicative atlas, most of the Thanet District now falls within a ‘Radon Affected Area’ (defined as an area where there is a 1% or more risk of homes being above the 200 Bq m-3 ‘Action Level’), and it highlights maximum percentage bands of 1-3% for most 1-km2 grids of the Thanet District.

However, this does not automatically mean that an individual property within these 1-km2 grids will have a radon problem. More accurate radon potential estimates for an individual home can be obtained through the following website: http://www.ukradon.org/


Exposure to high concentrations of radon can pose serious risks to health.

If you breathe in high concentrations of radon decay particles they can damage your lung tissue. The radiation decay products ionize genetic material, causing mutations that sometimes turn cancerous. Radon exposure is the second major cause of lung cancer after smoking[2].

[2] Catelinois, O; Rogel A; Laurier D et al. (May 2006) ‘Lung Cancer Attributable to Indoor Radon Exposure in France: Impact of the Risk Models and Uncertainty Analysis’, Environmental Health Perspectives 114 (9): 1361–1366: National Institute of Environmental Health Science


Air from the soil seeps into the lower pressure area of the house through cracks and gaps in the floor or walls. In some areas, this air will contain Radon gas. These Radon levels may become concentrated inside buildings and rise above the ‘Action Level’.


The estimated radon potential for an individual home can be obtained through the following website for a small fee. http://www.ukradon.org/

The government recommends that people in affected areas test their houses for radon. The test involves monitoring radon in the home with a simple, safe device for a period of three months. It costs around £40 and is available to anyone.

Test Kits are available from the http://www.ukradon.org/

The government, Public Health England and the Building Research Establishment (BRE) all recommend that if householders’ indoor radon levels are found to be above the ‘Action Level’ they should take radon reduction measures as soon as practical – and then take the test again to give themselves peace of mind that the measures have worked.


If you require any more information about Radon in the Thanet District you can contact the Environmental Protection Team on 01843 577000.

Advice can also be obtained regarding Radon in the Workplace from: http://www.hse.gov.uk/radiation/ionising/radon.htm


It is your average exposure to Radon that matters. Short-term exposure to high levels is not significant, if over the long term your average exposure is low. This means that if you have detected a problem, you can plan a solution that suits you, your house and your Radon level. Having decided on a solution, you should implement it as soon as practicable. The best approach is to stop Radon entering the house. If this is not possible, you need to be able to remove it when it gets in.

The aim is to reduce indoor radon levels to well below the ‘Action Level’. There are a number of ways in which this can be achieved.

  • Details are contained in a publication entitled: ‘Radon – a guide to reducing levels in your home
  • Following publication of updated BRE guidance, there are no special requirements for radon protection in new buildings and extensions in Thanet. For more information, you can call the Radon Hotline at the Building Research Establishment on 01923 664707.

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