Relationship between radon concentrations in indoor air and in soil gas

In the Ljubljana region, 53 schools were selected for measurements of radon concentrations in soil gas close to a school building, and indoor radon concentrations in one of the ground-floor classrooms of each building. The aim was to establish a relationship between radon concentrations in indoor air and in soil gas from the ground on which the building is situated. Soil gas radon concentrations between 2 and 14 kBqm super(-3) were found. Indoor radon concentrations ranged from 20 to 1,440 Bqm super(-3), with seven values exceeding 200 Bqm super(-3). It is concluded that good quality of the construction elements ensure low indoor radon concentration, regardless of high soil gas radon level.