Map reveals varying levels of radioactive gas radon around Dorset. Image: Public Health England. AN interactive map shows the hotspots of a radioactive gas in Dorset which is colourless, odourless and tasteless. Radon is formed by radioactive decay from the small amounts of uranium that can be found naturally in all rocks and soils. This means that it is everywhere. Public Health England, however, states that 'every building contains radon but the levels are usually low. 'The chances of a higher level depend on the type of ground.' The radiation emitted from the elements can increase the risk of cancer and it appears that those living in rural areas are surrounded by more levels of this radioactive gas than more urban areas like London.