Radon is a radioactive inert gas that is formed when uranium decays. Norway is among the countries in the world where indoor radon reaches its highest concentrations.
Illustration: DSA/Monica Egeli
About 10 per cent of Norway's housing stock has a radon concentration higher than 200 Bq/m3. In the great majority of cases the ground beneath buildings is the main source of elevated radon levels.
Radiation doses from radon are larger than doses from all other naturally occurring or man-made ionising radiation. Indoor radon is estimated to cause about 300 cases of lung cancer in Norway each year. The World Health Organisation (WHO) concludes that radon is the second most important cause of lung cancer, and that only smoking represents a higher lung cancer risk.
It is not possible to determine radon concentration in a home without taking measurements of indoor air. The Norwegian Radiation and Nuclear Safety Authority (DSA) requires this to be done using a track-etch detector. In living rooms with an annual average radon concentration over 100 Bq/m3, countermeasures are recommended to reduce the concentration. The concentration (annual average) should always be less than 200 Bq/m3.
What is the government doing?
The DSA has a public responsibility for radon, and research work and studies are conducted in fields dealing with this theme. Great importance is given to make information available. The DSA also supports the efforts of local authorities and others in mapping radon-prone areas and implementing counter-measures.
Local authorities are required to maintain an overview of the radon problem in their area. They are also required to ensure that radon levels remain below the intervention level in their buildings, e.g. schools, day care centres, municipal buildings and workplaces.