No abstract

An extensive radon survey was conducted in 2008-2011 in the framework of the Federal target program on the territory of 29 districts of Chelyabinsk Oblast. SSNTDs were used to measure indoor radon concentrations in public buildings, dwellings and industrial buildings. The results are stored in the database “Radon” owned by Research and Technical Center of Radiation-Chemical Safety and Hygiene of Federal Medical-Biological Agency. The paper presents the results of the analysis of spatial variability of indoor radon concentration and the relationship of this value with a set of geological predictors of radon potential of the territory integrated into a map of ecological and radiogeochemical zones. The results show that in all districts and the whole Chelyabinsk Oblast radon concentrations conform to a lognormal distribution, but in ten districts log-logistic distribution fits the data slightly better. Nevertheless, relative difference between the median values of indoor radon concentration calculated from the two fitted distributions yields zero. The results show that dose assessment based on the arithmetic means could lead to an overestimation of the doses from radon in 1.4 times on average compared to that based on the medians. The median value does not exceed 400 Bq/m3 in any of the surveyed territories and the 95th percentile lies between 96 and 1274 Bq/m3. The fraction of indoor radon concentrations above 400 Bq/m3 expected from the fitted distribution lies between less than 0.1 and 26.8%. The highest values of this fraction were obtained for the Sosnovsky, Kaslinsky, Bredinsky districts and the Miassky urban district (except for the city of Miass). A map of ecological and radiogeochemical zones in Chelyabinsk Oblast was released in 1993-1995 and it was based on a set of geological predictors of radon potential of the territory. We analyzed the relationship of these zones with the results of the radon survey. One-way ANOVA on ranks with the Bonferroni correction showed that there is no statistically significant difference at the 95% confidence level amongst the medians of indoor radon concentration on basement, ground and first floors in settlements, which are located on the territory of three of four of these zones and outside of the territory of all zones. In the fourth zone the median was even two times lower than outside of the zones. These results lead to the conclusion that the possibility of using this map as a map of radon-prone areas is very doubtful. Each datapoint stored in the “Radon” database has a number of additional properties, which allows analyzing other types of indoor radon concentration variability such as seasonal or floor-to-floor. It is expected that later this dataset could be used for estimating regional seasonal correction factors.

Современное состояние проблемы контроля радона Известно, что радон является основным фактором облучения населения Земли, вызывающим раковые заболевания. Среднемировая доза годового облучения от радона составляет около 1,2 мЗв, или 42% от всех известных природных и техногенных источников ионизирующих излучений [1]. Для населения России значение этого показателя оценивается почти в два раза выше-около 2,0 мЗв [2, 3]. Согласно данным Всемирной организации здравоохранения, до 14% всех заболеваний раком легкого обусловлено влиянием радона за счет ингаляции его короткоживущих продуктов распада [4] (вероятно, для населения России доля заболеваний выше). Однако негативное влияние радона поддается регулированию, и его можно снижать, в отличие от действия, например, кос

The authors share their experience and represent the historical overview of activities on public radiation protection against radon and other natural sources of radiation in Russia. Special attention is paid to the country’s first national radon program - Federal Target Program “Radon” (FTP “Radon”, 1994-1996). Organization, structure, main goals and objectives of the FTP «Radon» are discussed. In particular, it was noted that in a short period of time the country’s regulatory and methodological framework was developed. The scientific basis for identification of the radon prone areas and regulatory support for building construction at the sites was developed. The national SSND equipment was produced and QA/QC system implemented. The national and regional radon surveys have been performed. Unfortunately, the economic situation of those years did not allow to fully implement the planned set of measures at the federal and regional levels. Nevertheless the accumulated experience served as a scientific and technical basis for further improvements in this field and to be consistent with the modern radon regulatory issues and approaches developed by the international organizations (ICRP, IAEA, WHO).

Контроль содержания радона в зданиях проводится уже несколько десятилетий во многих странах мира, включая Россию. Однако до сих пор результаты контроля радона в помещениях нельзя считать надежными, поскольку сложившаяся практика не предусматривает количественную оценку неопределенности среднегодовой объемной активности (СОА) радона, как и его среднегодовой экви-валентной равновесной объемной активности (СЭА). Эта проблема достаточно подробно рассматривается в первой части статьи [1] (далее -Часть 1). Кроме того, в Части 1 представлен принцип, обеспечивающий надежность контроля радона в помещениях, поскольку он соответствует требованиям метрологии и современных стандартов. Этот принцип вводит новый параметр -коэффициент K V (t), который выражает неопределенность временных вариаций