广州地区教学环境空气中氡浓度调查

目的 研究广州地区教学环境空气中氡浓度,探讨教学环境氡的来源.方法 于2005年3-4月,8-9月,运用瞬时测量和累积测量方法进行室内空气中的氡浓度测量,并调查教室面积、装修时间、通风条件对氡浓度的影响,昼夜、季节与氡浓度的关系.结果 广州地区教学环境室内空气中氡浓度为(34.2±21.17)Bq/m3,新建筑物室内空气中氡浓度[(36.6±25.5)Bq/m3]高于旧建筑室内氡浓度[(20.1±8.48)Bq/m3],夜晚室内空气中氡浓度高于白天,6:00-7:00为最高值(165.6Bq/m3),冬季室内空气中氡浓度[(54.2±15.11)Bq/m3]高于夏季室内氡浓度[(17.3±7.31)Bq/m3].结论 广州地区教学环境空气中氡浓度算术平均值在我国标准范围内,教学环境空气中氡浓度在外界条件改变时有差异.     

阳江高本底辐射地区环境中氡及其子体的测量

测量了高本底辐射地区 (HBRA)和相邻的“正常”本底地区 (CA)空气中氡、及其它们的子体浓度和氡的平衡因子F。HBRA室内、外空气中平均氡浓度分别为 42 6和 17 3Bq/ ,CA分别为 13 2和11 7Bq/ 。HBRA室内、外氡子体α潜能值分别是 0 10 9和 0 0 5 1μJ/ ,CA室内、外分别是 0 0 45和0 0 41μJ/ 。子体α潜能浓度HBRA室内、外分别是 0 2 49和 0 0 5 3 μJ/ ,CA分别是 0 0 5 1和 0 0 2 5 μJ/ 。HBRA室内、外氡的平衡因子F分别是 0 46和 0 5 3 ,CA分别是 0 62和 0 64。     

放射卫生

940416上海市环境中氡水平及所致居民剂量/张浩然…//中华放射医学与防护杂志.一1992,12(6).一387～390 于1987年到1990年测定了上海市室内、室外氡浓度及其日变化”和季节变化数据。上海市氡与子体的平衡因子:室内为0.5,室外为0.7。住房氡浓度平均值l市区为11.2Bq·m一;城镇为10.5Bq·m一;农村为13.6Bq·m～,室外氡浓度年均值为5.1Bq·m一。市区居民居留因子:成人室内O.82,室外O.18;儿童室内O.87,室外O.13。1989年上海市各类住房人口加权年均有效剂量当量为O.53rosyl集体剂量当量为6 800man·Sv。图3表5参5940417秦山核电站环境氧的测…     

某退役稀土厂环境空气中~(222)Rn、~(220)Rn子体水平及土壤析出率调查

目的了解上海某稀土化工厂周围222Rn/220Rn子体浓度及土壤析出率水平。方法用BWLM-PLUS-S氡、钍射气子体测量仪测量222Rn/220Rn子体浓度以及ERS-2氡析出率仪和RAD-7测量222Rn/220Rn析出率。结果厂区室外222Rn/220Rn子体平衡当量浓度平均值分别是1.08Bq/m3和0.06Bq/m3,室内平均值分别是8.58Bq/m3和0.09Bq/m3;车间内222Rn/220Rn子体浓度平均值是14Bq/m3和0.13Bq/m3,办公室内平均值是3.16Bq/m3和0.05Bq/m3。厂区周围6处土壤中222Rn析出率最高为63.9mBq/(m2s),最低为6.3mBq/(m2s),平均18.9mBq/(m2s);222Rn析出率最高为1.72Bq/(m2s),最低为43.4mBq/(m2s),平均0.41Bq/(m2s)。结论厂区外环境、室内中222Rn/220Rn子体浓度在世界室内外水平之下,222Rn/220Rn析出率总体处于世界土壤的平均值范围内,只在个别测点偏高。     

福州市部分住房室内放射性水平检测结果分析

[目的 ]了解福州市住房室内放射性水平。 [方法 ]用 FD- 71型闪烁辐射仪检测室内 γ辐射水平。用 Markov法检测室内氡子体浓度。[结果 ]室内 γ辐射空气吸收剂量率均值为 15 .6 3× 10 - 2 μGy/ h。门窗关闭时氡子体浓度均值为 6 5 .5Bq/ m3,门窗打开通风换气后为 18.6 Bq/ m3。 [结论 ]室内γ辐射空气吸收剂量率均值与我省调查室内均值基本一致。通风换气是降低室内氡浓度有效而实用的方法。含有放射性物质的建筑和装修材料的生产、销售和使用必须符合有关国家卫生标准。     

北京某核设施周围室内氡水平调查与分析

目的调查北京地区某核设施周围室内氡浓度水平及其分布状况,为人群的辐射健康影响评价提供参考依据。方法选择北京某核设施周围10 km范围内的住宅和办公区33个室内监测点,分别在非采暖季和采暖季采用固体径迹法累积测量室内空气氡浓度。结果非采暖季室内空气氡浓度总体平均值为48.5 Bq/m~3,范围值为30~74Bq/m~3;采暖季室内空气氡浓度总体平均值为71 Bq/m~3,范围值为50~108 Bq/m~3;各楼层之间室内空气氡浓度平均值无明显差异。结论采暖季室内氡浓度高于非采暖季,应加强和改进室内通风措施以降低和控制室内氡的健康危害。     

居室中放射性污染调查与辐射剂量估算

目的 探讨不同类型房屋中放射性污染水平。方法 于2003年仡太原市某社区内监测了23间不同类型房屋的室内、外氡浓度及氡子体潜能γ剂量率，以及地面和墙壁表面氡析出率。同时还测定了室内自来水和煤制气中氡浓度，地下室、平房、楼房居室中来源于土壤和建材、室外空气、水、煤制气的放射性水平。最后估算了室内、外氡暴露的年有效剂量当量。结果 室内氡浓度、氡子体潜能γ剂量率均高于室外。地面氧析出率高于墙壁。自来水和煤制气中氡浓度均值分别为4.39～7．36Bq／m^3和11．55～51．07Bq/m^3。室内放射性污染主要来源于土壤和建材中的氡析出，其次是室外宅气中的氡及γ辐射，室内用水和煤气中氡及γ辐射的贡献很小。个体暴露于室内、外氡的年总剂量当量为1．94mSv。结论本次调查的所有膳室均符合我国《：室内空气质量卫生规范》的要求。调查结果为进一步研究居住环境中放射性污染奠定了基础。     

苏州市区居室内氡浓度及其致居民剂量估算

目的 了解苏州市区居民室内氡浓度及所致剂量。方法 采用双滤膜法，使用FT-648型测氡仪，采样15min，间隔1min，计数15min.结果 苏州市区居室内氡浓度均值为41．7，Bq／m3，平衡当量氡浓度为16．7Bq／m3，致居民支气管上皮组织、肺、性腺、骨髓及骨表面细胞的年吸收剂量分别为1421．7，285．6，2．1，2．4，2．4μGy／a，全身年有效剂量1．052mSv，通风对居室内氡水平有明显影响。结论 苏州市区居室内氡浓度与全球平均水平(40．0Bq／m3)接近。     

某金矿放射性职业危害调查与评价

调查山东省某金矿氡浓度、矿石放射性核素活度浓度及γ空气比释动能率,估算矿工接受年有效剂量。利用固体径迹探测器CR-39测量金矿222 Rn、220 Rn浓度;利用高纯锗γ谱仪分析矿石226 Ra、232 Th4、0 K活度浓度;利用环境剂量计测量γ空气比释动能率。结果表明,测量期间矿井下氡浓度由高到底依次为:第2期(2007年6—10月)为2130Bq/m3、第1期(2007年2—6月)为923Bq/m3和第3期(2007年10月—2008年2月)为577Bq/m3。全年氡浓度平均值为1210Bq/m3,氡及其子体所致矿工年有效剂量为7.6mSv。提示,该矿应采取加大通风能力等措施降低井下氡浓度;对井下矿工应按照职业照射人员的要求开展职业健康监护。     

黑龙江省室内外空气中氡及其子体浓度与所致居民剂量的研究

本文报道了本省室内、外空气中氡及其子体浓度与所致居民剂量的结果。全省319个室外测量点和413个室内测量点的空气氡浓度分别为6.7q·m^-3和13.3Bq·m^-3.室内、外氡子体浓度分别为2.5×10^-3WL和1.1×10^-3WL。室内外平衡因子分别为0.5和0.4.因吸入氡子体所致居民肺部年有效剂量当量为0.5mSv。     

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.     

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。     

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.     

Radon action level for high-rise buildings

Radon and its progeny are the major contributors to the natural radiation dose received by human beings. Many countries and radiological authorities have recommended radon action levels to limit the indoor radon concentrations and, hence, the annual doses to the general public. Since the sources of indoor radon and the methods for reducing its concentration are different for different types of buildings, social and economic factors have to be considered when setting the action level. But so far no action levels are specifically recommended for cities that have dwellings and offices all housed in high-rise buildings. In this study, an optimization approach was used to determine an action level for high-rise buildings based on data obtained through previous territory-wide radon surveys. A protection cost of HK$0.044 per unit fresh air change rate per unit volume and a detriment cost of HK$120,000 per person-Sv were used, which gave a minimum total cost at an action level of 200 Bq m(-3). The optimization analyses were repeated for different simulated radon distributions and living environment, which resulted in quite significantly different action levels. Finally, an action level of 200 Bq m(-3) was recommended for existing buildings and 150 Bq m(-3) for newly built buildings.     

Radon concentration in two largest cities in semitropical Taiwan.

Grab sampling either using the active charcoal method in combination with an ionization chamber or using a working level monitor was performed for the measurement of radon concentration in Taiwan's two largest cities Taipei and Kaohsiung. Long-term monitoring of radon concentration in dwellings and business buildings was also carried out with cellulose nitrate films as the alpha detectors. The average indoor radon concentration in these two cities is 17 +/- 6 Bq m-3. The outdoor radon concentration is about one-half of that on average. As assessed according to the model of UNSCEAR 1988, the induced effective dose equivalent is 0.67 mSv y-1. Radon concentration in coal mines showed an average of 88.5 +/- 9.5 Bq m-3.     

Indoor radon in the region of Brussels

The indoor radon (222Rn) concentration has been measured by charcoal detectors in 278 buildings in the region of Brussels, Belgium. The correlation with the nature of the subsoil can be studied in detail thanks to the available geotechnical map. With a geometrical mean indoor radon concentration of 19 Bq m(-3), Brussels can be considered as generally unaffected by the radon problem. No value higher than 400 Bq m(-3) (the EU reference level for existing houses) was measured in an occupied room. However, two factors that may enhance the risk are identified: the absence of a basement or a ventilated crawl space, and the presence of loess, under the house. About one third of the houses without basements or ventilated crawl spaces built on loess show an indoor radon concentration above 200 Bq m(-3) (the EU reference level for new houses).     

Quality control of mitigation methods for unusually high indoor radon concentrations

The present study's objective was to control the quality of different mitigation methods for unusually high indoor radon (222Rn) concentrations of up to 274,000 Bq m(-3) in a village (Umhausen, 2,600 inhabitants) in western Tyrol, Austria. Five years after mitigation, five different remedial actions were examined on their quality by means of measuring indoor radon concentrations with charcoal liquid scintillation radon detectors and with a continuously recording AlphaGuard detector. Mitigation method in house 1--a mechanical intake and outlet ventilation system with heat exchanger in the basement, combined with a soil depressurization system--was characterized by long-term stability. With most favorable air pressure (+100 Pa) in the basement, mean basement radon concentrations in the winter were reduced from 200,000 Bq m(-3) to 3,000 Bq m(-3) by this method 5 y after mitigation. Acting against experts' instructions, the inhabitants had switched off the ventilation system most of the time to minimize power consumption although it had been proven that ventilation reduced mean basement radon concentration by a factor of about 3 in the winter and about 15 in the summer. Mitigation method in house 2-soil depressurization with two fans and loops of drainage tubes to withdraw radon from the region below the floor and outside the basement walls, and from soil below that part of the house with no basement-had been the most successful remedial measure until the winter of 1999 (i.e., 6 y after mitigation), when micro-cracks opened and consequently mean basement radon concentration increased from 250 Bq m(-3) to 1,500 Bq m(-3). Measures to block these microcracks and to minimize soil drying are being developed. Five years after mitigation, the remedial method used in house 3--a multilayer floor construction, where a fan was used to suck radon from a layer between bottom slab and floor-reduced winter mean radon concentration from 25,000 Bq m(-3) to 1,200 Bq m(-3), with the ventilation on and the basement door open. Mitigation method in house 4--a basement sealing technique--was unsuccessful with almost identical radon concentrations during all the five years since mitigation had started. Mitigation method in house 5--a waterproof basement technique especially for future homes--reduced mean basement radon concentration below 300 Bq m(-3) and mean ground floor radon concentration below 200 Bq m(-3), which is the Austrian action level for newly constructed buildings. These findings indicate that even in areas with extremely high radon concentrations, effective mitigation of indoor radon can be achieved provided that house-specific long-term, stable mitigation techniques are applied.     

A nation-wide survey on indoor radon from 2007 to 2010 in Japan

In two previous nation-wide surveys in the late 1980s and early 1990s, Japanese indoor radon concentrations increased in homes built after the mid 1970s. In order to ascertain whether this trend continued, a nation-wide survey was conducted from 2007 to 2010. In total 3,900 houses were allocated to 47 prefectures by the Neyman allocation method and 3,461 radon measurements were performed (88.7% success). The fraction of reinforced concrete / concrete block buildings was 32.4%, similar to the value from national statistics. Arithmetic mean (standard deviation, SD) and geometric mean (geometric SD) of radon concentration after adjusting for seasonal fluctuation were 14.3 (14.7) and 10.8 (2.1) Bq/m(3). The corresponding population-weighted values were 13.7 (12.3) and 10.4 (2.0) Bq/m(3), respectively. It was estimated that only 0.1% of dwellings exceed 100 Bq/m(3), a new WHO reference level for indoor radon. Radon concentrations were highest in houses constructed in the mid 1980s and decreased thereafter. In conclusion, arithmetic mean indoor radon in the present survey was slightly lower than in previous surveys and significant reductions in indoor radon concentrations in both wooden and concrete houses can be attributed to alterations in Japanese housing styles in recent decades.     

降札温泉空气氡浓度水平调查

目的在既往调查的基础上,进一步了解当地居民、游客、治疗疾病的患者的洗浴模式等情况,并对当地的室内外氡浓度进行测量。方法采用ATD短期累积测量法和连续测量法测量室内外氡浓度,并与国家相关标准进行对比。结果室内外氡浓度几乎全部高于电离辐射防护与辐射源安全基本标准(GB18871-2002)中的住宅中氡持续照射的优化行动水平400Bq/m3(平衡因子0.4)。部分浴室中氡浓度高于地热水应用中放射卫生防护标准(GBZ124-2002)中地热水浴疗室平衡当量氡浓度400Bq/m3的控制限值。结论降札温泉室内外氡浓度水平非常高,会对附近的居民、游客和患者的健康造成影响。