The risk of radon induced lung cancer in rental accommodation

The radon concentration in the indoor air was measured in 221 rental accommodations located in 53 buildings, including 28 multi-occupant houses and 25 single-family terraced houses constructed between 1850 and 2010. The overall annual mean value of the concentration of radon in the indoor air was 30.7 Bq/m3. The annual mean value of the concentration of radon in the indoor air exceeded 100 Bq/m3 in 5.9% of the accommodations, all located in single-family terraced houses. For single-family terraced houses the annual mean value of the concentration of radon in the indoor air exceeded 100 Bq/m3 in 52% of the houses and 12% exceeded 200 Bq/m3. Approx. 77% of the accommodations exceeding 100 Bq/m3 for the concentration of radon in the indoor air had a content between 100 and 200 Bq/m3 and 23% had a content exceeding 200 Bq/m3. Significant differences in the concentration of radon in the indoor were found in accommodations located in multi-occupant houses. Additionally, the risk of the concentration of radon in the indoor air exceeding 100 Bq/m3 in accommodations in multi-occupant houses was found to be very low, but if any the risk was highest in accommodations on the ground floor in a building constructed with slab on ground.