Radon is a naturally occurring radioactive gas that has no taste, smell or colour. It is produced by the radioactive decay of naturally occurring uranium which is found in very small quantities in all soils or rocks. Radon can migrate through fissures and pores in the rock and soil to reach the surface where it is quickly diluted in the air. However, radon that enters enclosed spaces like buildings can sometimes reach relatively high concentrations.
When radon decays it forms tiny radioactive particles which may be inhaled into the lungs. Anyone who is exposed to high concentrations of radon over a long period of time is at an increased risk of developing lung cancer. This risk is greatly increased if the person is also a smoker.
Radon levels inside a property vary depending on the types of underlying rock and factors related to the construction of the property, how it is ventilated and how it is used.
Radon is measured in Becquerels per cubic metre (Bq/m3). Affected Areas are designated where there is predicted to be greater than a 1% probability of the Action Level being exceeded. In residential property the Action Level is 200Bq/m3 and in commercial premises it is 400Bq/m3. The average level in UK homes is 20 Bq/m3. Work carried out jointly by the Health Protection Agency and British Geological Survey has resulted in the production of an Atlas that indicates the probability of the radon level in a property exceeding the Action Level.
The World Health Organisation has recently introduced a new Target Level of 100Bq/m3. The Target Level is regarded as the ideal outcome for remediation works in existing buildings and protective measures in new buildings. If the result of a radon assessment is between the Target and Action Levels, action to reduce the level should be seriously considered.
Radon in Domestic Dwellings
In Argyll the geology is complex and the potential for radon to affect property varies widely and although the Radon Atlas can only provide an indication of whether a property is likely to be affected by radon. Householders can commission a report from UKradon which will tell you the estimated probability that this particular address or an address to be built on a plot of land is above the Action Level for radon. However, it is important to note that the only way to find out whether a property is above or below the Action Level is to carry out a radon measurement. It is a simple process to carry out a radon measurement using two simple detectors and further details can be found on the UKradon website. The Action Level refers to the annual average concentration in a home, so radon measurements are carried out with two detectors (in a bedroom and living room) over three months to average out short-term fluctuations.
If the result of a radon test shows that the Action Level has been exceeded it is strongly recommended that work is undertaken to reduce levels to as low as practical taking into account the type and construction of the property. The Building Research Establishment has provided guidance to builders and householders on methods of reducing radon in the home.
Radon in Commercial Premises
The amount of radon that collects in a building depends on its location, structure and how it is used. Work environments vary greatly in size and nature, but excessive radon levels can occur in almost any type of workplace and employers have a legal duty under the Health and Safety at Work Act to protect their employees. This should include potential radon exposures and usually requires testing in any workplace premises that are in radon Affected Areas. To find out if the premises are in an Affected Areas an employer can obtain a Radon Risk Report. If the results of testing indicate an elevated level then remedial action will be needed and in most cases this will involve carrying out minor building works to reduce the radon to an acceptable level.
A guide is available from the Health and Safety Executive (HSE) which describes how to measure radon levels in workplaces and the practical cost effective methods that are available for reducing radon levels in workplace buildings. Further advice on measurement and technical solutions for dealing with radon in the workplace is contained in BRE Report BR 293 Radon in the workplace
Radon in New Buildings
Contact your local Building Standards office for advice on the construction of new buildings in radon Affected areas.