High concentrations of radon are of concern because worldwide studies have linked it with lung cancer. People exposed to high levels are more prone to lung cancer and smokers are at greater risk.
Radon is a natural radioactive gas found in soil and rocks. It has no colour, taste or smell. Levels vary from country to country, between regions and even between neighbouring houses. It is quickly diluted to the atmosphere in open spaces, but the situation can be different in the enclosure of a home. Typically, this occurs when radon moves from a region of high pressure within the soil into the marginally lower pressure in homes, brought about by such factors as wind and temperature and heating the home.
The Health Protection Agency (HPA) oversee radon gas surveillance in the UK. They can carry out tests at the request of householders but the particular results of such tests remain confidential between the householder and the HPA. House sellers are not legally obliged to volunteer any information they have about radon tests on their properties but if you ask for it they must tell you.
Radon monitoring devices are small, simple pieces of equipment that are left in a relevant location in a building, usually for about three months, before being sent off to a lab to work out what the Radon levels are.
Further information is available on the HPA website.