222Rn air concentration and radiation exposure levels in the Lantian Xishui karst cave of Shaanxi, China

22Rn air concentrations in the Lantian Xishui karst cave of Shaanxi, China, were measured by continuous monitoring during a complete annual cycle (March 2004-February 2005) and annual doses for tour guides and visitors were estimated. The 22Rn air concentrations in the cave vary between a minimum of 383.6 Bq m(-3) and a maximum of 2,015.7 Bq m(-3), with an annual average of 1,100.4 Bq m(-3). Distinct seasonal variation of radon air concentrations inside the cave was observed. The maximum average radon concentration occurred in summer and the minimum average radon concentration occurred in winter. The annual effective dose to tour guides varies between an average of 1.2 mSv and 4.9 mSv depending on different equilibrium factors together with different dose conversion factors proposed in the literature, which is lower than the international recommendations. In all cases, the annual effective doses to visitors are well under the 1 mSv maximum suggested dose for a member of the public for one year.     

Seasonal variation in indoor radon concentrations in dwellings in six districts of the Punjab province, Pakistan

An indoor radon measurement survey has been carried out in six districts of the Punjab province. These included Gujranwala, Gujrat, Hafizabad, Sialkot, Narowal and Mandibahauddin districts. In each district, 40 representative houses were chosen and indoor radon levels were measured in these dwellings in autumn, winter, spring and summer seasons using CR-39 based NRPB radon dosimeters. After exposure to radon, the CR-39 detectors were etched in 25% NaOH at 80 degrees C and track densities were related to radon concentration levels. From the observed data, average radon concentration levels and a seasonal correction factor were calculated. The average 222Rn concentration level was found to vary from 40 +/- 15 to 160 +/- 32 Bq m(-3) and 38 +/- 17 to 141 +/- 26 Bq m(-3) in the bedrooms and living rooms of the houses surveyed, respectively. The annual mean effective dose received by the occupants has been calculated using ICRP (1993 Ann. ICRP 23) and UNSCEAR (2000 Sources and Effects of Ionizing Radiation (New York: United Nations)); it varied from 1.2 to 1.7 mSv and from 1.8 to 2.4 mSv, respectively.     

Nationwide survey of radon levels in Korea

A nationwide radon survey was conducted to provide data on the annual average indoor radon concentration in Korean homes. This survey also provided data on the variation of radon concentration with season, house type, and building age. The arithmetic mean (AM) of annual radon concentration in Korean homes was 53.4 +/- 57.5 Bq m(-3). The indoor radon concentration showed a lognormal distribution with a geometric mean (GM) and its standard deviation (GSD) of 43.3 +/- 1.8 Bq m(-3). The radon concentrations in the traditional Korean-style houses were about two times higher than those in apartments and row houses. The average annual outdoor radon concentration was 23.3 Bq m(-3). The average annual effective dose to the general public from radon was 1.63 mSv y(-1).     

Radon 222Rn in residential buildings of Swieradów Zdrój and Czerniawa Zdrój

Swieradrów Zdrój and Czerniawa Zdrój are located in Region Izera Block. A total of 789 radon passive dosimeters were distributed in 183 dwellings in these town Swieradów Zdrój and Czerniawa Zdrój to measure the indoor radon concentration in 1999. Three-five measurements were performed in each dwelling, one in the basement, and the others in the main bedroom, in the kitchen, in the bathroom, since these rooms are the most frequently occupied. In addition, the occupants of each dwelling were requested to answer a questionnaire in which a number of questions about the building, ventilation habits and other related aspects were formulated. A charcoal detectors (Pico-Rad system) were used in experiment. It is a passive short-term screening method of radon gas concentration measurements. The indoor radon level was found to range from 14.8 Bq/m3 to 5,723.9 Bq/m3. The arithmetic mean overall indoor concentration was 420.4 Bq/m3 and the geometric mean was 159.7 Bq/m3. The average concentration of indoor radon, which reflects the real risk for inhabitants, is 193.5 Bq/m3. The results hand a log-normal distribution. In Poland, an action level of 400 Bq/m3 was recommended for existing buildings and 200 Bq/m3 for newly built (after 1.01.1998) buildings. In about 23% rooms the level of Rn-222 were above the top limit of 400 Bq/m3. The highest average concentrations were present in a basement (mean 919.9 Bq/m3). A decrease of average activity were observed at the upper levels: at the ground floor (225.2 Bq/m3), at the first floor and at the higher floors (137.6 Bq/m3). The above results indicate that radon emission from the ground provides the main contribution to the radon concentration measured in dwellings indoors in Swieradów Zdrój and Czerniawa Zdrój. The effective dose to the population of the Swieradów Zdrój and Czerniawa Zdrój from indoor radon and its progeny can be derived from this data if we use an equilibrium factor of 0.4 between radon and its progeny and assuming an indoor occupation index of 0.8. Taking into account that a conversion coefficient of 1.1 mSv per mJ h m-3 is recommended in ICRP 65 for members of public, the measured average annual dose is then about 3.3 mSv per year.     

Regular radon activity concentration and effective dose measurements inside the great pyramid with passive nuclear track detectors

Radon activity concentrations and equilibrium factors inside the great pyramid of "Cheops" were measured with passive nuclear track detectors. The variation of these concentrations in location was investigated. Seasonal variation of radon activity concentrations with winter maximum and summer minimum were observed inside the pyramid. The 1-y average radon activity concentration ranged from a minimum of 20 to a maximum of 170 Bq m(-3). Results show that the yearly average equilibrium factor between radon and its progeny was assessed as 0.16 and 0.36 inside the pyramid and near entrance, respectively. Moreover, the estimated annual effective dose was 0.05 mSv to tour guides and varied from 0.19 to 0.36 mSv for the pyramid guards; for visitors the average effective dose was 0.15 microSv per visit. These are lower than the 3-10 mSv y(-1) dose limit recommend by ICRP 65.     

崇明县空气中氡浓度水平调查与评价

目的 了解崇明县室内外氡浓度水平并估算其所致公众的受照剂量。方法 根据2010年全国人口普查崇明县乡镇人口比例、房屋建筑类型、建筑年代和主体建筑材料等对测量样本进行分类选择。使用美国Durridge公司制造RAD7型电子氡气检测仪对室内外氡进行测量,数据采用SPSS 17.0软件进行统计分析。结果 本次调查的室内²²²Rn浓度范围为5.75~195.29 Bq/m³,平均浓度为(25.76±2.07) Bq/m³。约有73.89%的房屋内氡浓度低于40 Bq/m³。室外²²²Rn浓度的范围为5.70~19.32 Bq/m³,平均浓度为(9.92±1.43) Bq/m³。结论 本次调查的崇明县室内氡浓度均未超过国家推荐的控制限值。崇明县居民吸入氡所致人年均有效剂量为0.74 mSv。     

Methodology of radon monitoring and dose estimates in Postojna Cave, Slovenia

Due to the specific work regime in the Postojna Cave, which depends primarily on the daily number of visitors, and on seasonal variations in air radon concentrations, an optimal methodology for radon and progeny measurement and dose calculation was sought. The program of measurement throughout the years was optimized, and now comprises 3-mo exposures of etched-track detectors, and twice a year, 8-10-d measurements using continuous monitors. Radon concentrations range from about 500 Bq m(-3) in winter to about 6,000 Bq m(-3) in summer, and equilibrium factors range from 0.42 to 0.69 in winter and from 0.33 to 0.86 in summer. Radiation doses from radon decay products for employees in the cave were calculated according to the ICRP 65 methodology. The basic input data are radon concentrations and equilibrium factors at two selected locations in the cave and the records of the time spent by a worker in the cave. Effective doses received by employees annually ranged from 0.02 to 8.4 mSv.     

Population dose due to natural radiation in Hong Kong

In densely populated cities such as Hong Kong where people live and work in high-rise buildings that are all built with concrete, the indoor gamma dose rate and indoor radon concentration are not wide ranging. Indoor gamma dose rates (including cosmic rays) follow a normal distribution with an arithmetic mean of 0.22 +/- 0.04 microGy h(-1), whereas indoor radon concentrations follow a log-normal distribution with geometric means of 48 +/- 2 Bq m(-3) and 90 +/- 2 Bq m(-3) for the two main categories of buildings: residential and non-residential. Since different occupations result in different occupancy in different categories of buildings, the annual total dose [indoor and outdoor radon effective dose + indoor and outdoor gamma absorbed dose (including cosmic ray)] to the population in Hong Kong was estimated based on the number of people for each occupation; the occupancy of each occupation; indoor radon concentration distribution and indoor gamma dose rate distribution for each category of buildings; outdoor radon concentration and gamma dose rate; and indoor and outdoor cosmic ray dose rates. The result shows that the annual doses for every occupation follow a log-normal distribution. This is expected since the total dose is dominated by radon effective dose, which has a log-normal distribution. The annual dose to the population of Hong Kong is characterized by a log-normal distribution with a geometric mean of 2.4 mSv and a geometric standard deviation of 1.3 mSv.     

寿光日光温室春秋季氡浓度变化趋势及辐射剂量估算

目的初步了解日光温室中氡浓度的本底值和变化趋势,估算温室作业人员氡及其子体造成的年均辐射剂量,探讨温、湿度对氡浓度的影响。方法 2009年5月和10月分别对选定的2座温室进行调查,使用Model1027连续测氡仪和干湿球温度计对温室环境中的氡浓度、温度和相对湿度进行8h连续监测。结果在测定范围内,5月温室氡浓度、温湿度最大值分别为355.0Bq/m3、30.5℃和93%,10月各指标的最大值分别为235.4Bq/m3、37.5℃和72%;根据实际情况粗略估算的温室作业人员年均辐射剂量为0.8686mSv。结论温度和相对湿度可能是影响温室中氡浓度的重要因素;温室作业人员由于职业因素所造成的氡及其子体的辐射剂量略高于当地平均室内暴露所造成的辐射剂量,氡子体对作业人员健康的影响应引起重视。     

黄山市环境辐射水平及居民受照剂量调查分析

目的研究黄山市环境辐射水平及居民受照剂量,为辐射防护和经济建设提供背景资料。方法采用FD-71型闪烁辐射仪,测量室内外、道路γ辐射剂量率;采用低本底闪烁测氡仪,测量氡浓度;采用γ能谱分析方法,测量建材中放射性核素226Ra、232Th、40K的含量。结果室内、室外、道路γ辐射剂量率均值分别为12.2×10-8Gy.h-1、8.5×10-8Gy.h-1、8.6×10-8Gy.h-1。地球γ辐射水平室内比室外高,平均比值为1.44,道路与室外的γ辐射水平差异无统计学意义。室内和室外宇宙射线辐射剂量率分别为2.7×10-8Gy.h-1和3.0×10-8Gy.h-1。室内、室外氡浓度均值分别为27.3 Bq.m-3和13.2 Bq.m-3。建筑材料除碳化砖及个别类型中的样品外,其他建材内、外照射指数均低于国家标准。结论黄山市环境辐射外照射所致居民人均年有效剂量当量为0.92mSv,其辐射水平属正常本底水平;室内、外氡浓度致居民受到的人均年有效剂量当量为1.88 mSv。在世界值范围内,传统建材放射性核素含量与世界建材典型值比较接近,其他建材有部分则高于世界建材典型值,应引起相关部门的注意。     

Survey of indoor radon concentrations in Fukuoka and Kagoshima prefectures

It is now well established that radon and its daughter products account for nearly half of the average population exposure to ionizing radiations and that radon is the greatest single source of natural radiation to the population. Radon and its daughters are alpha-emitters, which are more biologically damaging than beta- and gamma-radiations. A nationwide survey of radon concentration was conducted by the National Institute of Radiological Sciences in order to estimate the contribution of radon and its daughters to the population dose in Japan. Authors surveyed indoor radon concentrations in Fukuoka and Kagoshima prefectures as part of this project. A passive type radon dosimeter, in which a sheet of polycarbonate film as the alpha-ray detector was mounted, was used to measure indoor radon concentrations. The resulting distribution of the average annual indoor radon concentrations in both prefectures can be characterized by an arithmetic mean of 24.4 Bq/m3 and a standard deviation of 13.1 Bq/m3, by a geometric mean of 22.2 Bq/m3, and by a median of 20.7 Bq/m3. The geometric means of the distributions for Fukuoka and Kagoshima were 25.4, and 18.4 Bq/m3, respectively. Radon concentrations were also generally high in winter and low in summer. Regarding the analysis of correlations between the concentrations and construction materials, radon concentrations were generally high in Japanese houses with earthen walls and in concrete structures. These results showed that seasons, the type of building materials, and regional differences were significant factors in the variation of indoor radon concentration.     

A survey of 222Rn concentrations in dwellings of the town of Metsovo in north-western Greece

A radon survey has been carried out of indoor radon concentrations in dwellings located in the town of Metsovo, in north-western Greece. To measure indoor radon concentrations, CR-39 detectors were installed in randomly selected houses and were exposed for about 3 mo, during summer and winter. Gamma spectroscopy measurements of the soil's radium content also were performed. The indoor radon concentration levels varied from 17.6 to 750.4 Bq m(-3), while the radium concentration of soil varied from 4.9 to 97.1 Bq m(-3). Seasonal variation of the radon levels and the influence of house features and soil are discussed.     

汕头市环境中氡水平及所致居民剂量的分析

本文报道了汕头市室内外环境中氡土气浓度及其子体潜能浓度。研究结果显示：本市环境天然辐射水平较高,室内外氡浓度分别为２００４、１６０５Ｂｑ／ｍ３,土气浓度分别为４１８５、３１１５Ｂｑ／ｍ３,氡子体分别为０００２５４、０００２６８ＷＬ,土气子体分别为０００３３１、０００２４５ＷＬ。汕头市居民吸入氡土气及其子体所致的年有效剂量当量为１２６ｍＳｖ,其中２２２Ｒｎ及其子体贡献了０９０３ｍＳｖ,即氡及其子体所贡献的年有效剂量当量占７５％,较接近于温带地区而高于全球正常本底地区（０９７ｍＳｖ）的水平     

Radon concentrations in elementary schools in Kuwait

Measurements of indoor radon concentrations were performed in 25 classrooms in the capital city of Kuwait from September 2003 to March 2004 using track etch detectors. The investigation was focused on area, ventilation, windows, air conditioners, fans, and floor number. All the schools have nearly the same design. Mean indoor radon concentration was higher for case subjects (classrooms) than for control subjects (locations in inert gas, p < 0.001). The mean alpha dose equivalent rate for case subjects, 0.97 +/- 0.25 mSv y, was higher than the radiation dose equivalent rate value of control subjects, 0.43 +/- 0.11 mSv y. The average radon concentrations were found to be 16 +/- 4 Bq m for the first floor and 19 +/- 4.8 Bq m for the second floor after subtraction of the control. These values lead to average effective dose equivalent rates of 0.40 +/- 0.10 and 0.48 +/- 0.12 mSv y, respectively. The equilibrium factor between radon and its progeny was found to be 0.6 +/- 0.2.     

Occupational doses from radon in Spanish spas

Recent international recommendations have included exposure to natural radiation as one of the sources to monitor in certain occupationally exposed groups. Among those mentioned are workers in thermal spas, who may be exposed to high radiation doses due to the high concentration of radon in the indoor air of the spa. This paper presents the methodology and the results of an evaluation of radiation doses to the staff in different thermal spas in Spain. Different series of samples were collected and measurements made for the radon concentrations in water in 54 spas and in air in 20 spas. In six of the latter group, the air radon concentration was studied in different working areas occupied by the employees. The radon concentrations in water were between <2 and 775 x 10(3) Bq m(-3). The radon concentrations in air were between <10 and 5,200 Bq m(-3). The latter were used to estimate the dose received by each occupational group in the spa by taking into account the radon concentration in their main working area. By means of an exposure-dose conversion factor of 1.43 Sv per J h m(-3), the estimated effective doses were found to lie between 1 and 44 mSv y(-1). This upper limit is higher than the recommended annual limit of 20 mSv y(-1) for an occupational dose.     

南宁市地铁1号线各站段氡浓度水平以及地表γ剂量率水平研究

目的 掌握南宁市地铁1号线车站内氡浓度水平以及γ射线辐射水平,评价其对地铁工作人员造成的辐射剂量。方法 采用闪烁瓶法和瞬时监测相结合的方法,对南宁市地铁1号线氡浓度水平和γ射线瞬时剂量率进行监测,并对数据进行分析和比较,根据联合国原子辐射效应科学委员会推荐的评价方法估算地铁工作人员受到氡及其衰变子体以及γ辐射水平造成的人均年有效照射剂量,评价其卫生学效应。结果 南宁市地铁1号线全线氡浓度水平均值为18.5 Bq/m³,地铁氡及其子体给工作人员造成的人均年有效剂量为0.133 mSv/a,地铁站地表γ射线辐射水平均值为0.097 μSv/h,所造成的地铁工作人员年有效剂量0.194 mSv/a,二者造成的总剂量为0.327 mSv/a。结论 南宁市地铁1号线氡浓度水平和γ射线瞬时剂量率不会对地铁工作人员和乘客造成额外明显的受照负担。     

Radon concentration measurements and personnel exposure levels in Bavarian water supply facilities

As part of a study covering the whole of Bavaria, the southern most of Germany's 16 states, water supply facilities were examined to determine the radon (222Rn) concentrations in ground water and indoor air and the radon exposure to the staff working in these buildings. Bavaria can be divided into ten geological regions of different geogenic radon potential. From each region, a number of water supply facilities proportional to the size of the region were selected for measurements. Over 500 of a total number of 2,600 water supply facilities were asked to take a 1-L groundwater sample and expose several track-etch detectors in order to obtain the mean room concentration of the main staff work places. In addition, for a period of 2 mo, the personnel had to wear a track-etch detector during the time they spent in the supply facilities. The resulting measurements were then used to estimate their individual effective dose of radon and its progenies. In the East Bavarian crystalline region, the region of the highest geogenic radon potential within Bavaria, indoor radon gas concentrations of up to 400 kBq m(-3) were observed. About 10% of the process controllers in this region are subjected to an annual effective dose of more than 20 mSv. In the other Bavarian regions, only 2% of staff exposure levels exceed this limit. The correlation between the radon concentration measurements of the indoor air, the ground water, and individual personnel exposure levels was determined. The average ratio of the radon indoor air to the processed groundwater concentration is 0.14. But due to the different types of ventilation in the various supply facilities, there can be great variations in this figure. Therefore, there is no clear relationship between the groundwater and the indoor air concentration of a supply facility. This study also reveals no clear relationship between radon indoor air concentrations and the personnel exposure levels of a supply facility.     

Radon activity levels and effective doses in the Perama Cave, Greece

An investigation of atmospheric radon levels in the Perama Cave, North-western Greece, has been carried out using CR-39 detectors. The detectors were placed at various locations along the guided cave pathway and exposed during different sampling periods. Mean concentrations amounting to 925 +/- 418 and 1,311 +/- 352 Bq m-3 were recorded in the summer and winter months, respectively. As the Perama Cave is one of the most popular in Greece, attracting more than 85,000 tourists per year, the quantification of effective doses to staff and visitors was an issue of importance. Doses less than 5.1 microSv per visit were calculated for tourists and around 1.8 mSv y-1 for seasonal guides, employed for periods of high visiting frequency. The annual exposure of permanent guides was estimated to fall between 3 and 10 mSv, which is the range of action levels recommended by the ICRP.     

Radon in Irish schools: the results of a national survey.

This paper presents the results of a survey of radon concentrations in Irish primary and post-primary schools. The objective of this survey was to assess the distribution of radon in Irish schools and to identify those requiring remedial work to reduce radon exposure to children and staff. All primary and post-primary schools were invited to participate in the survey. Indoor radon concentrations were measured during the academic year using integrating passive alpha track-etch detectors with a measurement period from three to nine months. The survey was carried out on a phased basis from 1998 to 2004 and is one of the most comprehensive of its kind undertaken in Europe. Measurements were completed in 38 531 ground floor classrooms and offices in 3826 schools, representing over 95% of the approximate 4000 primary and post-primary schools in Ireland. Of these, 984 schools had radon concentrations greater than 200 Bq m(-3) in 3028 rooms and 329 schools had radon concentrations in excess of 400 Bq m(-3) in 800 rooms. The average radon concentration in schools was 93 Bq m(-3). This results in an annual average effective dose to an Irish child from exposure to radon of 0.3 mSv per year, assuming that the long-term radon concentration is equal to the radon concentration present during the working hours and that the annual average occupancy is 1000 h per year. A programme of remediation of schools with radon concentrations above 200 Bq m(-3) has been put in place.     

沈阳典型住宅居室内外环境氡的水平变化

环境氡(~(222)Rn)子体可诱发肺癌已得到公认。Harley等提出了一种用于预测环境~(222)Rn所致肺癌的危险度模型,估计在不吸烟的患肺癌的居民中约有20～100%的肺癌来源于环境~(222)Rn及其子体的照射、另一估算认为不吸烟患肺癌的人中3—20%的肺癌来源于环境~(222)Rn及其子体的照射。Cohen估算美国由于节能而减少室内通风率将使因现有~(222)Rn水平所致肺癌(约为10000例/年)增加一倍。居室内外环境~(222)Rn的水平与变