Radon in the soil

Transport of Radon in soil

Part of the radon originating from the decay of radium located in rocks and soil particles is emitted in the pore volume of soil and stones. Due to atmospheric conditions (temperature, air pressure, weather), the radon concentration in a depth of less than one meter varies considerably. With increasing depth, the radon concentration rises to a saturation value.

The permeability of the soil plays a decisive role. Generally, starting from a depth of one meter, the radon concentration in the soil air changes only in a minor way. Due to the half-life (circa 1,600 years) of Radium-226, the parent of radon, the radon soil air concentration is stable over a long term. If the radon concentration of a particular site is known, new measurements are only necessary after significant interventions done in the underground.

Cracks and rifts simplify the transport of radon in the underground. Therefore the local radon concentration can be much higher in the proximity of chasms, subsidences or boundaries between different rocks.

Furthermore, radon can be dissolved in groundwater and transported through the geological underground.