Radon in indoor air

Radon is an odourless and colourless gas naturally present in soil and rocks. It seeps through cracks in the foundations of homes and can accumulate in the premises. As it is unstable, radon disintegrates and emits radiation which is the second cause of lung cancer after smoking.

Every year, 200 to 300 people die in Switzerland because of radon¹. These deaths could be avoided by reducing the concentration of radon in homes. This reduction may be carried out in a simple manner (ventilation, installation of an extractor fan) or in a more complex manner (sealing the soil, draining the floor) depending on the case.

As radon is colourless and odourless, the only way to detect its presence is to perform analyses. A radon mapping consultation in Switzerland (the Federal Office of Public Health's site) can be used to find out the risk depending on the region lived in, but cannot quantify the concentration in your house because variations in the soil or the construction may lead to enormous differences, even between two neighbouring houses.

The maximum concentration of radon in living areas is set at 1,000 Bq/m³ (becquerels per cubic metre of air, a unit used to measure the quantity of radon contained in a volume of air) and the official guideline value that must not be exceeded is 400 Bq/m³. However, recent studies from the World Health Organisation have shown that the toxicity of radon has been underestimated and the Federal Office of Public Health has published recommendations advising that the threshold of 300 Bq/m³ is not exceeded.