Radon (Rn) is a radioactive element zero of the group of the periodic system D. I. Mendeleev, number 86, inert gas. The most important are its alpha-emitting isotopes: Rn222 (radon, the former name of the emanation of radium) with a half-life 3.8 days and Rn220 (thoron) with a half-life 54.5. Breaking down, Rn222 and Rn220 give rise to a group of short-lived isotopes (the daughter products of radon and thoron).
Rn222 contained in atmospheric and soil air, in natural waters and natural objects containing radium. Rn222 widely used in medical practice (see alpha therapy).
The presence Rn222 and Rn220 with their affiliate products (the latter usually in the form of aerosols in the air of working premises (at the mining and processing of uranium-radium and thorium ores, preparation of radon baths, and so on) creates professional hazards to persons in these areas. The decrease of this hazard is ensured good ventilation.
Maximum permissible concentrations Rn222 in the air: for professionals 3·10-11 Curie/l, for the population - 3·10-12 Curie/L.

Radon (Radon; Rn) - radioactive chemical element in the periodic table. Ever since. number 86, at. weight 222. The name given by the principal, the most long-lived isotope - 86Rn222. Element radon is sometimes referred to as an emanation (86Cm). It is known 19 isotopes of the element radon; of them, except 86Rn222, two natural - toron (86Rn220) and action (86Rn219). 86Rn222 formed from 88Ra226 (see radium); this inert radioactive gas with a half-life 3,8229 day. Decays with the emission of alpha-particles (energy 5,49 MeV, mileage in the air 4.0 cm, in biological tissues around 0.04 mm) and very weak ' -radiation, it gives rise to a group of child products 86Rn222 (radium And, In radium, and so on - the isotopes of lead, bismuth and other metals present in more or less everywhere, where there are 86Rn222. The basic unit of measurement for the amount 8eRn222 is Curie. One Curie corresponds 0,0065 mg 86Rn222 and is at normal temperature and pressure, the volume of 0.65 mm3.
In nature 86Rn222 contained in atmospheric and soil air, waters (mainly mineral), and wherever there are 88Ra226 in dispersed state.
For therapeutic purposes 86Rn222 receive from solutions of chlorine or bromide salt 88Ra226. These salts are kept in a special glass vessels - bubblers, where accumulated 86Rn222 after a certain period of time is translated by passing air through the solution 88Ra226 in the right amount of water. Both natural and prepared with the help of solutions 88Ra226 radon water and air, enriched 86Rn222, used for treatment of some diseases (see alpha therapy, Balneotherapy).
Prolonged inhalation of air, enriched 86Rn222 and its daughter products (there are usually in the form of aerosols, emit alpha, beta and gamma radiation)can have a harmful effect on the body. This creates a professional hazard for workers serving hospitals with radon baths, engaged in extraction and processing orangeday ores and others To reduce this occupational exposure use complexes hygienic measures aimed at reducing the content of 86Rn222 and its progeny in the air we breathe. Maximum permissible concentration of 86Rn222 in the air for persons who by the nature of their work dealing with it is 3·10-11 Curie/l, for the population - 3·10-12 Curie/L. These concentrations are calculated on the assumption that along with eoRn222 B0 the air we breathe 100% balance all of his short-lived subsidiary products (up RaC'+RaC" inclusive).