Lung doses from radon in dwellings and influencing factors

Factors influencing the population doses from inhalation of radon and its decay products in Norwegian dwellings are discussed. Radon concentrations in the indoor air can show large variations depending on the type of building materials (containing radon) used in the construction of the walls and also on the ventilation rate. The ventilation rate is in turn dependent on factors such as wind speed and direction and the temperature. The radon exhalation rate through the walls is dependent on atmospheric pressure. It was shown that the effective dose equivalent from inhalation of radon daughters in concrete houses increased by a factor of 20 as the ventilation rate decreased by a factor of 10. The current population effective dose equivalent from inhalation of radon daughters in Norwegian houses is about 3 mSv/year which is the largest contributor to the population exposure. (UK)