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Briefly about radioactive gas radon.
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Radon is inert gas, colourless, tasteless, without smell. Of the three radon isotopes (radon, toron, actinon), which are radioactive gases, the most radiation dangerous for the population is radon-222. This gas is generated as a result of decay of radium-226, which is presented in rocks and it constantly comes into the atmosphere from the bowels of the earth. Radon can extend to big distances from the place of its formation and accumulate in the atmosphere of buildings. As the numerous researches show, the volumetric activity of radon in the air of dwelling houses can be changed from several Bq/m3 to 100000 Bq/m3.
Reference : Bq/m3 - unit of measurement of volumetric activity of radon in the air ( Bekkerel in the cubic meter of the air in a dwelling ), 1Bk equals one decay for a second.
Decaying, radon gives off alpha particles which cause irradiation of skin surface and lung tissue. Besides, radon decay is accompanied by the formation of radioisotipes of lead, bismuth, polonium. Decay products of radon are radioactive solid substances, which form so called aerosols - these particles are so small that they can stay in suspension in the air for a long time, together with the air they can get into the lungs and cause internal irradiation. Radon causes approximately 54% of the doze of irradiation, which every inhabitant of the Earth receives regularly, and real dozes can highly ( dozens and thousands ) differ from average ones. According to the modern knowledge, risk of death because of cancer of lungs, connected with the high volumetric activity of radon in the air of the building, is the most considerable.
In Lugansk oblast and Lugansk itself the maximal levels of volumetric activity of radon-222, registered in the air of dwelling houses, reach 2000 Bq/m3, in the air of semi-basements - 5800Bq/m3 , and in the air of underground - 12000Bq/m3. The only effective and reliable way of revealing radon danger in a building is a direct measurement of the volumetric activity of radon or its decay products.
In accordance with the Law of Ukraine "About the defence of population from ionization radiation" every person who lives or stays temporarily on the territory of Ukraine has the right of defence from the influence of the ionization radiation. This right is provided by conducting the complex of measures for prevention the influence of ionization radiation that is higher than the stipulated doze limits of radiation on the organism of a person, compensation for the excess of the stipulated doze limits of the radiation and compensation for damage caused in consequence with the influence of ionization radiation (clause 3). The main doze limit of individual irradiation of population must not exceed 1 m3v of effective doze of radiation per one year (clause 5).
According to the norms of radiation safety of Ukraine (NRBU-97) the levels of activity (permissible figure) for dwellings of children's, sanatorium and medical establishments by the capacity of the equivalent doze of gamma-radiation total 0,26 mkSv/h, by the equivalent balance volumetric activity (EBVA) of radon-222 - 50Bq/m3.
Reference: while staying in a dwelling where the volumetric activity of radon in the air totals 300Bq/m3 (EEVA=120Bq/m3), in the course of 2000 hours per year (for 8 hours during working days) a man receives the effective doze of irradiation that equals 1,46 mSv.
Since 2001, as a result of the examination of 400 dwellings in pre-school children's institutions, schools, medical centers which are situatde in radon dangerous regions of Lugansk oblast, it is established that for the most part of the dwellings (62%) EEVA of radon-222 in the air exceeds the level of activity, stipulated by norms of radiation safety of Ukraine (1997).
For elimination of radon danger Scientific production enterprise "OPYT" on the base of the results of the radiation examinations of buildings and dwellings work out recommendations and conduct effective antiradon measures. Among them are the simplest ones - the optimization of ventilate regime and labour-intensive: the equipment of undergroun ventilation and installation of electric ventilate systems. In 104 of the dwellings where the antiradon measures were held the concentration of radon was successfully reduced to its norm.
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The head of the laboratory of radiation control,
director of Scientific Production
Small Joint Enterprise "OPYT"
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Makhnyov I. A.
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03680, Ukraine, Kyiv, Palladina Avenue, 34a.
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| Director: |
Mr Igor A. Makhnyov |
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