夏冬两季室内通风降氡能耗分析

通过对室内氡的来源及氡浓度平衡的分析,建立了室内氡浓度的估算模型。在此基础上,建立了通风降氡能耗与室内氡浓度之间的计算模型,对空调房间内冬夏两季通风降氡能耗和通风换气率进行模拟。通过通风换气率整合两个模型,模拟得出室内通风降氡能耗与室内氡浓度二者之间的关系。以湖南省衡阳市住房进行模拟分析,分析结果表明,室内通风降氡能耗随着室内氡浓度降呈指数类增长,当室内氡浓度值较低时,空调通风降氡能耗要高于高浓度时降低相同氡浓度时所需能耗。     

室内氡的来源及纵深防御

室内氡对于人体健康的危害日益引起关注。从室内氡的主要来源入手,针对室内氡的各个来源提出了纵深防御的方法,从而可以更有效地做好防氡降氡工作。     

民用建筑中防氡降氡材料开发应用现状研究

本文介绍了氡的危害和室内的氡污染现状,分析了民用建筑材料的防氡降氡机理,对民用建筑防氡降氡材料的开发应用现状进行了详细的调查研究,并且对防氡降氡材料的发展方向进行了讨论。最后针对民用建筑防氡降氡材料提出改进措旌,民用建筑防氡材料将向着纳米材料、绿色环保、长效低成本和高防氡率等方向进一步的发展。     

地下建筑中氡气对人类健康的危害及其防护

室内氡气及其短寿命子体产生和对人类健康的危害，造就了人类认识氡危害的历史，同时世界范围氡研究热逐步形成。地下建筑物渗漏水在氡的传输过程中起着重要作用。本文介绍了控制室内氡污染的方法和ＲＧ－ＹＤ型抑氡防水剂作为高效防水抑氡密封材料的抑氡效果。     

居室内氡的来源及防治

介绍了氡的危害、室内氡的来源以及降氡防护措施，通过了解氡的来源及特征，以使人们准确判断室内氡浓度高的原因，以便针对性的采取防护措施，保护人类自身的健康。     

广州市室内氡浓度调查报告

我公司于2008～2009年承担了全国室内氡调查项目中广州地区的调查工作。本次调查中,按全国室内氡浓度调查方案的要求,按行政区、人口分布、建筑物和种类等分布了采样点,共布了146个采样盒,回收了135个。结果表明,广州市室内氡平均浓度为32.70Bq/m3,最大值156Bq/m3,最小值4Bq/m3。这次全国10个城市室内氡浓度调查结果的均值为34.9Bq/m3。在广州室内氡调查结果比较低的主要原因是人们长期开窗通风的生活习惯。与工程验收检测的氡浓度相差甚远,主要的原因是检测时的状态不同。     

室内氡污染的危害及防治

简要介绍了氡的产生和氡污染的来源以及室内氡浓度的影响因素,结合氡的物理化学性质分析了室内氡污染对人体健康的危害,并针对室内氡污染的来源具体阐述了室内氡污染的控制措施和治理方法,以期创造健康的室内环境。     

利用检测手段来预防民用建筑工程室内氡的危害

采用美国Durridge公司生产的RAD7型α能谱氡气测氡仪,对3个有代表性的工程土壤中氡浓度、建筑物所用建筑材料的表面氡析出率和最终竣工验收室内环境氡指标的检测,利用检测手段全方位地阐述预防民用建筑工程室内氡的危害。     

空调室内氡及粒子污染的传播及其数值模拟

室内氡(含氡子体)污染的传播与粒子(悬浮颗粒)污染在室内的传播过程相关,通风空调气流对氡及粒子污染的传播影响很大。本文详细阐述了室内氡和粒子的来源和特点、氡及其子体在空气中的传播机理以及除去方法,分析了通风空调系统对室内氡及子体传输的影响、以及氡在空气中迁移的动力学模型,分析比较了通风室内氡及粒子污染物迁移沉降过程的数值模拟方法,提出了空调气流环境下氡及粒子污染传播及其数值模拟中的关键问题。     

室内放射性物质氡的来源、危害与控制

阐述氡对人体的危害;室内空气氡主要来源(岩石土壤、建材、燃气、地热水等);室内氢的防治方法(通风排气、应用空气清新器、吊扇电扇、室内装修);室内氡的控制标准与检测方法.     

Human disease from radon exposures: The impact of energy conservation in residential buildings

The level of radon and its daughters inside conventional buildings is often higher than the ambient background level. Interest in conserving energy is motivating home-owners and builders to reduce ventilation and hence to increase the concentration of indoor generated air contaminants, including radon. It is possible that the current radiation levels in conventional homes and buildings from radon daughters could account for a significant portion of the lung cancer rate in non-smokers. Moreover, it is likely that some increased lung cancer risk would result from increased radon exposures; hence, it is prudent not to allow radon concentrations to rise significantly. There are several ways to implement energy conservation measures without increasing risks.     

Radon protection for new buildings: a practical solution from the UK

If indoor radon levels are to be significantly reduced across Europe it is essential to ensure that all new buildings built in areas affected by radon are protected. In the United Kingdom the Building Research Establishment Ltd (BRE) has been carrying out research on behalf of the Department of the Environment, Transport and the Regions (DETR) to develop protective measures for use in new buildings. This work commenced in the mid-1980s and has resulted in the development of a range of practical cost-effective techniques for providing radon protection in new UK buildings. Guidance has been developed in support of the Building Regulations for England and Wales. First published in 1991 the technical solutions have been gradually improved in light of experience gained on site. Likewise, the areas for which the guidance applies have also been revised in light of radon surveys carried out by the National Radiological Protection Board. This continuous process of refinement is scheduled to result in a further version during 1999. The techniques developed in the UK mainly rely upon passive radon barriers, which are low cost and simple to install. Even in the worst affected areas of the country, where some 30% of existing houses have radon levels greater than 200 Bq/m3 (UK recommended action level), houses with protection measures regularly result in indoor radon levels close to 20 Bq/m3 (UK average for all house types). Radon protective measures are now being installed routinely in many parts of the UK. The cost of installation has reduced as protection has become a matter of routine through regulation, so that currently radon protection is unlikely to cost much more than 0.25% of the total construction cost of a typical UK house. It is our view that many of the techniques developed in the UK could be used directly or with minor modifications in other countries in Europe. This paper describes these latest techniques and approaches used in the UK to successfully provide radon protective measures.     

Experiences in radon-safe building in Finland

A study was made of radon-safe buildings in 300 Finnish low-rise residential buildings using data obtained from a questionnaire study. The study also aims at finding the main defects in design and implementation and how the guidance given on radon-safe buildings in slab-on-grade houses has been followed. According to the guidelines, the prevention of the flow of radon-bearing air from the soil into the house is recommended to be carried out through installation of aluminised bitumen felt and use of elastic sealants. Second, as a precaution perforated piping should be installed in the subsoil of the floor slab. The median indoor radon concentration in the houses was 155 Bq/m3. This is 32% lower than the median of the estimated reference values. The action level of 200 Bq/m3 was still exceeded in 40% of the houses. In most houses with slab-on-grade the prevention was based only on the installation of a sub-slab depressurisation system. Sealing was performed in a low number of houses. In 80% of houses with a sub-slab piping connected to an operating fan, radon concentration was below the action level of 200 Bq/m3. In houses with piping but no fan, the corresponding fraction was only 45%. Sub-slab piping without a fan had no remarkable effect on radon concentration. In houses with crawl-space and edge-thickened slabs, radon concentrations were low. The choice of foundation system thus significantly affects the indoor radon concentration. The importance of complete and careful sealing work should be stressed in advice and guides concerning radon prevention.     

Cost effectiveness analysis of radon remediation programmes

The economic implications of regulations governing radon gas level identification and remediation in buildings are poorly understood, and attempts to address these issues have been criticised for lack of comparability. It is imperative therefore that a general model for the economic evaluation of radon remediation programmes is adopted to ensure comparability between studies and settings and to increase the usefulness of the results to decision makers. This paper presents general guidelines for the use of cost-effectiveness analysis (CEA) as an economic appraisal tool in the evaluation of radon reduction and prevention programmes. The data requirements for a CEA of radon remediation programmes concern both costs and outcomes. These components are discussed with respect to: programme objectives, comparator choice, perspective, time horizon, discounting, uncertainty, and final ratios. Adhering to clear guidelines concerning these aspects of evaluations will facilitate meaningful evaluation of radon remediation programmes. Finally, by evaluating the radon remediation programmes using methods applied to other health interventions (such as lung cancer prevention interventions), comparisons using the same metric can be made across policy areas.     

Radon in soil gas — Exhalation tests and in situ measurements

Radon in soil can move into buildings resulting in high radon daughter concentrations. The foundation of a dwelling should be adapted to the radon “risk” which is determined by the radon concentration and the air permeability of the soil. Different measuring procedures are discussed in this paper, both in situ measurements of radon content and laboratory tests on radon exhalation from different types of soils at different water contests.     

Indoor Radon Reduction in Crawl-space Houses: A Review of Alternative Approaches

An analysis has been completed of the performance, mechanisms, and costs of alternative technologies for preventing radon entry into the living areas of houses having crawl-space foundations. Sub-membrane depressurization (SMD) is consistently the most effective technique, often providing radon reductions of 80-98% in the living area. It has a relatively high installation cost, but a moderate annual operating cost. Forced crawl-space depressurization is the second most effective, giving reductions of 70-96%. Crawl-space depressurization is less well demonstrated than is SMD, and performance will vary with crawl-space tightness and weather, but it will be a primary option when large radon reductions are needed in buildings with crawl-spaces which are inaccessible for installation of SMD. Crawl-space depressurization has a lower installation cost than SMD, but its operating cost may be three times higher. Natural crawl-space ventilation and forced crawl-space pressurization each typically provides roughly 50% reduction or less in the living area. The lack of a clear benefit of crawl-space pressurization in most installations probably indicates that the crawl space is in fact not being pressurized. Crawl-space sealing and barriers (as stand-alone methods) usually give little or no reduction.     

Impact of constructional energy‐saving measures on radon levels indoors

Energy‐efficient building refurbishment has the aim of saving energy and thus reducing CO₂ emissions. Increased energy efficiency of a building often implies reduced air exchange. Together with other indoor air quality problems, this may lead to an increase in indoor radon concentration (Rn‐222). In order to investigate the extent of this problem, measurements of radon concentration in energy‐efficient refurbished and low‐energy houses (passive houses) were carried out. Track etch detectors were exposed in each type of building over a period of 1 year. A reference sample of non‐refurbished non‐passive buildings was drawn from the National Radon Database for comparison. Buildings were selected that have the same radon relevant properties and were built on comparable geological subsoil like those investigated. The reference sample was compiled in such a way that the measured values from the rooms on the ground floor of the refurbished and passive houses were each assigned a measured value from the database. The statistical analysis shows that the houses refurbished for energy efficiency have a wider distribution of radon concentrations indoors than the non‐refurbished ones. Both the mean value and the median of the radon concentration have nearly doubled in buildings refurbished for energy efficiency. The difference is statistically significant. On the other hand, there is no significant difference between the distributions of passive houses and houses not refurbished for energy efficiency.     

Variation in residential radon levels in new Danish homes

Radon‐222 gas arises from the radioactive decay of radium‐226 and has a half‐life of 3.8 days. This gas percolates up through soil into buildings, and if it is not evacuated, there can be much higher exposure levels indoors than outdoors, which is where human exposure occurs. Radon exposure is classified as a human carcinogen, and new Danish homes must be constructed to ensure indoor radon levels below 100 Bq/m³. Our purpose was to assess how well 200 newly constructed single detached homes perform according to building regulations pertaining to radon and identify the association between indoor radon in these homes and municipality, home age, floor area, floor level, basement, and outer wall and roof construction. Median (5–95 percentile) indoor radon levels were 36.8 (9.0–118) Bq/m³, but indoor radon exceeded 100 Bq/m³ in 14 of these new homes. The investigated variables explained nine percent of the variation in indoor radon levels, and although associations were positive, none of these were statistically significant. In this study, radon levels were generally low, but we found that 14 (7%) of the 200 new homes had indoor radon levels over 100 Bq/m³. More work is needed to determine the determinants of indoor radon.     

Modeling ventilation and radon in new Dutch dwellings

Indoor radon concentrations were estimated for various ventilation conditions, the differences being mainly related to the airtightness of the dwelling and the ventilation behavior of its occupants. The estimations were aimed at describing the variation in air change rates and radon concentrations to be expected in the representative newly built Dutch dwellings and identifying the most important parameters determining air change rate and indoor radon concentration. The model estimations were compared with measurements. Most of the air was predicted to enter the model dwelling through leaks in the building shell, independent of the ventilation conditions of the dwelling. Opening the air inlets was shown to be an efficient way to increase infiltration and thus to decrease radon concentration. The effect of increasing the mechanical ventilation rate was considerably less than opening the air inlets. The mechanical ventilation sets the lower limit to the air change rate of the dwelling, and is effective in reducing the radon concentration when natural infiltration is low. Opening inside doors proved to be effective in preventing peak concentrations in poorly ventilated rooms. As the airtightness of newly built dwellings is still being improved, higher radon concentrations are to be expected in the near future and the effect of occupant behavior on indoor radon concentrations is likely to increase. According to the model estimations soil-borne radon played a moderate role, which is in line with measurements.