Radon, a naturally occurring radioactive gas that is
produced by the radioactive decay of uranium in rock,
soil, and water, is of great concern because of the potential
for the gas to become concentrated in buildings and
homes. The higher the uranium levels in the rocks, the
greater the chances that a home or building may have
radon gas contamination. Once the parent material
decays into radon, it dissolves into the water contained
in the pore spaces between soil grains. A fraction of
the radon in the pore water volatilizes into the soil atmosphere
gas, rendering it more mobile via gas-phase
diffusion.