What is radon and why is it a problem?
Radon is a radioactive gas produced by radioactive decay of radium, which itself comes from the decay of uranium. The production of radon gas depends on the concentration of these radionuclides in rocks and soils. The distribution of radon is hence related to the underlying geology. Higher levels tend to be from very old rocks, usually granitic in origin. Radon gas from these rocks can be trapped in poorly ventilated buildings, thus giving the occupants a larger than normal radiation dose.
