Radon concentrations in living spaces
Radon is a naturally occurring radioactive noble gas in the soil, it is invisible, odorless as well as tasteless. Radon concentrations in the soil can vary greatly depending on the soil conditions. The radon activity concentration is measured in Becquerel (Bq). Radon enters buildings through leaks in building components adjacent to soil, where it can accumulate due to low air exchange. On average, about 1% of the radon gas concentrations present in the soil can be detected in buildings with leaks.
According to the Federal Office for Radiation Protection, about 5% of all lung cancer deaths in Germany can be attributed to radon. This makes radon the second most important risk factor for lung cancer after smoking.
Radon itself is not causative for the lung diseases, but the secondary products such as polonium, bismuth and lead, which are formed by the decay. These attach themselves to dust particles in the air, are inhaled, and accumulate in lung tissue, where they decay further. There is no threshold below which there is no risk. The reference limit for indoor radon is 300 Bq/m3. According to the WHO, as little as 100 Bq/m3 poses a health risk.