Where Do Noble Gases Occur?
With the exception of radon, all noble gases are contained in the air in small amounts around a total of 1 percentage by volume. They are gained by fractioned distillation of liquefied air. The most abundant noble gas in the air is argon with a 0.9 percentage by volume. Helium can be found in some natural gas reservoirs. Large amounts of helium exist on the sun, where it is formed by nuclear fusion of hydrogen. The short-lived radon is generated by radioactive fission. In some places – near Bad Gastein, Austria, for example – it escapes from the rocks in larger quantities.
