Finnish homes have high radon contents

The radon content of indoor air is easy to measure. The average radon content of Finnish homes is 120 becquerels per cubic metre (Bq/m3). It is estimated that there are 70,000 Finnish homes in detached, semidetached and terraced houses where the maximum value set by the Ministry of Social Affairs and Health for the radon content (400 Bq/m3) is exceeded. Radon is formed when the uranium contained in the ground and in the bedrock undergoes radioactive decay. The fact that Finish homes may have the highest concentrations of radon in the world stems from three reasons: geology, building methods and climate. Sand and gravel eskers that are easily permeated by gases are an inexhaustible source of air rich in radon. The material for the Finnish radon study, published originally in summer 1996, has now been reanalysed. According to the new calculations, about 250 Finns per year develop lung cancer because of exposure to radon in indoor air. Radon poses a higher risk to smokers than to nonsmokers. When smoking is stopped, the risk of lung cancer attributable to radon is also reduced. (orig.)