The Cornwall Radon Gas Centre

Contractor to:

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Special Needs Centres

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Architects

Builders

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What Is Radon?

Radon is formed during the radioactive decay of uranium into a non-radioactive isotope of lead. This whole process takes many millions of years. Radon, unlike its parent and daughter isotopes, behaves as a gas and is no longer locked up in the rocks and soils of our planet. Once the radon atom is formed, it migrates (the rate will depend on the soil structure) through the ground to the surface and becomes part of the air we all breathe. The radioactive particles of radon and its daughters may become concentrated in enclosed environments such as buildings or caves. Radon is a colourless and odourless gas. You cannot taste it or hear it seeping into your home. Although it is commonly associated with granite areas, it is the uranium content of the rock or soil that is important, together with the ground structure.

Porous, cracked or fissured rocks or soils will allow soil gasses and released radon to move more easily though them, thus the amount of radon reaching the surface may be independent of the source concentration. Uranium can occur in areas where there is no granite, such as Derbyshire where the associated rock type is limestone, or Northamptonshire (ironstone) and Somerset (red sandstone).

Uranium was present when our planet was formed. It is at the head of a chain of unstable isotopes which are losing mass and energy to eventually achieve a stable form of lead. During this ‘decay series’ the original uranium atom will become different elements which include radium and radon. It will take many billions of years for all the uranium to become lead.

Buildings

The most common reason for radon contamination is the pressure difference generated by wind effects and the higher temperature inside a building creating a chimney or suction effect. External air is drawn though the soil, collecting any radon present, into the building via floor and wall joints/cracks.

Water

Radon will dissolve into groundwater and can be transported some way from the source. When the water is exposed to air the radon is released. If a well or bore hole is supplied from such water, the use in an enclosure such as a dwelling or greenhouse will release radon into that environment. Showers and sprays are a prime release method and the greater the water usage, the greater the potential radon problem.