Radon, a radioactive gas, moves indoors from soil and rock into buildings. This infiltration is influenced by the air pressure and occurs through building joints, utility openings, cracks, or porous block walls, especially when the pressure inside the building is lower than the soil leading to the accumulation of radon indoors.
Indoor radon levels depend on several factors:
Radium Concentration in Soil and Underlying Rock: The presence of radium in the soil and rock beneath the building is the primary source of radon. Higher radium concentrations result in more radon production.
Radon Release from Parent Material: The ability of radon to escape from the solid material containing radium affects its availability for migration into buildings.
Soil and Rock Permeability: The capacity of radon to move through the rock and soil fractures and pores determines how easily it can enter a building. Porous or fractured materials allow radon to migrate more readily.
In summary, the accumulation of radon indoors is a function of the radium content in the soil, the release of radon from the parent material, and the permeability of the soil and rock. These factors collectively determine the risk and extent of indoor radon contamination.
Full article: Radon Infiltration and Accumulation in Buildings