What is Radon?

Radon (symbol Rn) is a chemical element with atomic number 86 and atomic weight 222. It is a radioactive, colourless, odourless and tasteless noble gas. It has a density of 9.73 kg/m³ which makes Radon one of the densest substances that remains a gas under normal conditions.

According to the World Health Organisation (WHO), radon is the second leading cause of lung cancer after smoking, responsible for an estimated 3% to 14% of lung cancer cases worldwide. The gas is produced naturally from the radioactive decay of uranium and thorium present in soils, rocks and building materials. It can accumulate in enclosed spaces such as homes, basements, schools and workplaces, making regular monitoring essential for health and safety compliance.

Detecting radon requires specialised instruments. Common methods include scintillation-based detectors, ionisation chambers and nuclear track etch detectors. At Advatech UK we supply radiation sensors suitable for radon detection and measurement, supporting both professional environmental monitoring and personal safety applications. Many countries have established regulatory limits for radon concentration in indoor environments, and regular testing is recommended to ensure compliance and protect occupants from prolonged exposure.

Learn about Radon - a naturally occurring radioactive gas formed from the decay of thorium and uranium. Health risks, detection and mitigation. Thorium and uranium are the two most common radioactive elements on Earth with their naturally occurring isotopes having very long half-lives (many billions of years). As radon itself decays, it produces other radioactive elements called radon progeny (formerly called daughters) or decay products. Its most stable isotope, 222Rn, has a half-life of 3.8 days.