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THE SWISS RADON PROGRAMME

G. Piller, G.A. Roserens and W. Zeller
Swiss Federal Office of Public Health, Division of Radiation Protection, CH-3003 Bern
Tel: +41 31 324 10 41
Fax: +41 31 322 83 83
E-mail: georges.piller@bag.admin.ch
Web: www.admin.ch/bag

The very high indoor radon concentrations found in the western part of Switzerland in the early
80th were at the origin of an extended research programme between 1987 and 1991. The results
obtained showed a real need for a further detailed radon programme. This should be based on the
state of knowledge, take economical aspects into account and be practically orientated. The main
aim is to deal with elevated concentrations. Thus three principal pillars were defined to achieve this
goal: legislation, communication and formation.
In 1994, the Swiss Legislation on Radiological Protection fixed a limit value of 1000 Bq/m 3 and a
guideline value of 400 Bq/m 3 for residential and recreational premises. After the investigation of
about one half of the 3000 municipalities, areas with high concentrations were found principally in
Alpine and Jura regions. But, values overcoming the limit were also found on the Swiss Plateau. In
more than 90% of the measured houses, the radon concentration is situated below the guideline
value, but in about one percent the radon concentration exceeds the limit. The arithmetic mean
value is 75 Bq/m 3 for inhabited rooms.
The communication with different target groups regarding radon and its harmful effects on health
is very important too. House owners must be motivated to perform measurements and to carry out
remedial work if necessary.
Finally, construction experts must know the different possibilities to reduce the radon gas
concentrations in the residential and recreational premises. Therefore, an efficient collaboration
with educational establishments and the different professional associations has to be realised.