Radon is a colorless, odorless, and tasteless radioactive gas that naturally forms from the decay of uranium in soil, rock, and water. It occurs both in outside air and in buildings and can be harmful to health in high concentrations. According to the World Health Organization (WHO), no more than 100 radon atoms may decay in one cubic meter per second. This means that a reference value of 100 Bq/m³ must not be exceeded.
The classification used for the analysis of a location’s susceptibility to radon is based on data from the Federal Office for Radiation Protection, which provides information on the average radon concentration of indoor air in buildings.