Assessment of Indoor Radon Concentrations in Dwellings for Baghdad Governorate by Using RAD-7 Detector

In the present work, radon gas concentrations in different dwellings in Baghdad governorate are measured by using RAD-7 detector. The results have shown that, the radon gas concentrations ranged between (40.67 ± 3.1 Bq/m3) to (190.00 ± 2.7 Bq/m3) with an average value (113.66 ± 30.2 Bq/m3);in the first one we draw the map radiations for indoor radon gas concentrations in Baghdad governorate. We would like to mention that the present study is considered to be very important and vital because it is concerned with people health and safety in the first place.

Influence of Geological Factor on Indoor Radon Concentrations in Dwelling of Queretaro,Mexico

In this study, radon-222 concentrations were measured within 34 houses distributed in the northern, southern, and central areas of the city of Querétaro in 2007. The objective of this study was to establish the spatial distribution of radon with respect to geological faults and its relation to certain environmental variables. For each sampling site, the radon-222 concentration was analyzed as a function of various climate variables, relative humidity, temperature, and atmospheric pressure, in addition to the ventilation of the house and distance of each site from any geological faults in the area. A multivariate statistical technique was used to analyze these variables based on two components. For component 1, the relative humidity and temperature had the greatest weight, 0.677 and 0.492, respectively, while for component 2, the greatest weights corresponded to radon and the temperature with 0.693 and 0.609, respectively. The average radon concentration across the entire sampling period was 38.92 Bq/m3, the minimum detected value was 6.01 Bq/m3?for site 91GAG0607, and the maximum detected value was 225.95 Bq/m3?for site 91CAM20907. This last value is outside the standards permitted by the Environmental Protection Agency of the United Stated, which is 148 Bq/m3?for indoor environments. With respect to geological faults and their relationship to radon-222, the concentrations for the sampling sites had no relationship to the closeness or distance to these faults.

An Indoor Radon Survey in Three Different Climate Regions in Mexico, and the Influence of Climate in the Obtained Values

In this paper we present the results of a survey of indoor radon concentration levels in Mexico. In order to investigate whether differences in climate translate into significant differences in indoor radon concentrations, the country was divided into three climate regions: the northern semi-desert region, the central semitropical region and the southern tropical region. The survey was carried out using nuclear track methodology. The dosimeters employed for the survey were based on the passive closed-end cup device, developed at the Physics Institute of the National Autonomous University of Mexico, and used PADC as detector material. A well-established protocol for chemically etching and reading the detectors was followed. Average annual temperatures differ between regions (from 15℃ to 28℃) but vary relatively little within each region. Atmospheric temperature is one of the most important factors which need to be considered when carrying out a survey of indoor radon concentrations because temperature largely determines building ventilation habits, and ventilation habits are known to have significant effects on indoor radon concentrations. Other factors, including building construction materials, architectural styles, geological and hydrological characteristics, and seismicity, vary from region to region and within each region. In each of the three regions low levels of indoor radon (from 37 to 179 Bq·m-3) were found.

Relationship among cancer,indoor radon and geology from Gejiu area

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A pilot survey on indoor radon concentration in Beijing

Objective:To explore the level of indoor radon concentration especially after recent 3 decades’great economic development in metropolis Beijing,so as to describe the outline of indoor radon level in Beijing.Methods:A one-year integrated measurement on 800 dwellings was carried out from September 2018 to August 2019.Passive integrated radon cup monitor with CR-39 as an alpha-track detector was adopted for the survey.As a pilot study,measurement scheme was designed in detail.For measurement quality control,the background track density of CR-39 was strictly defined and controlled throughout the operation of the survey.Results:The annual geometric and arithmetic mean of radon concentration of the surveyed are(39.3±12.9)and(42.0±13.7)Bq/m^(3),respectively,varying from(12.1±2.5)to(119.0±7.8)Bq/m^(3).Radon concentration of the ground floor dwellings is obviously higher than that of other floors.No difference of radon level is found among the dwellings of other floors.Higher radon concentration in buildings built after 2010 is obtained compared with buildings built in 1980s,1990s,and 2000s.Conclusions:There is no big change of radon concentration level in dwellings in Beijing area observed in general compared with a previous survey performed more than ten years ago.For high-rise buildings,building materials are suggested to be the main source of indoor radon.For higher radon concentration in buildings built in latest ten years,the change on building materials and indoor ventilation rate are thought to be the causes,further study in detail is needed to clarify.

建材析出氡浓度持续监测研究及其应用

建筑材料析出的氡扩散至房屋内部导致室内氡浓度增加,对居住者产生健康威胁。提出了一种建材析出氡浓度持续监测方法,将自制具有不同放射性含量的建材实验样品块和氡浓度持续监测系统放置于密闭恒温容器内进行长时间监测,结果表明在2~9 h密封时间内建材析出氡浓度与密封时间的线性相关系数为0.99以上,连续密封72 h时氡浓度的析出量仍在增加,未出现饱和趋势。将氡浓度持续监测系统应用于室内氡浓度监测,当浓度超过报警阈值后自动开启通风系统进行空气置换,可实现快速排氡,有效改善室内空气质量,避免居住者长期暴露在高氡浓度环境中。

Indoor^(222)Rn Levels and Effective Dose Estimation of Academic Staff in izmir-Turkey

Objective To investigate the annual effective doses from indoor radon received by academic staff in the Faculty building. Methods Measurements of indoor radon concentrations were performed in the Arts and Sciences Faculty of Dokuz Eylul University for two surveys of about 1 month duration respectively using the SSNTD （Solid State Nuclear Track Detectors） method with LR115 detectors. Time integrated measurements comprised different locations inside the faculty building： classrooms, toilets, canteen and offices. Homes of academic staff were also tested for radon. Results The aritthmetic mean radon concentration is 161 Bq m-3 with a range between 40 and 335 Bq m-3 in the Faculty. Six offices and three classrooms have a radon concentration above 200 Bq m-3. The results show that the radon concentration in classrooms is generally higher than in offices. Based on the measured indoor radon data, the annual effective doses received by staff in the Faculty were estimated to range from 0.79 to 4.27 mSv, according to UNSCEAR methodology. The annual effective doses received by staff ranged from 0.78 to 4.20 mSv in homes. On average, the Faculty contributed 56% to the annual effective dose. Conclusion Reported values for radon concentrations and corresponding doses are within the ICRP recommended limits for workplaces.

Physical Factors Affecting the Interior Radon-Concentrations

Researchers have realized that radon-contaminated air inside buildings is a principal way of human exposure to certain healthy-risks. A model is developed to estimate radon concentrations which consider various parameters: in indoor air radon (radon-222) concentration, air permeability of ground, air pressure difference between outdoor and indoor at ground level, ventilation of building ground and number of air changes per hour due to ventilation. The radon-222 transport into building might dominated by diffusion, pressure driven flow or/and a mixture of both depending on the actual values of the various parameters. So, in several and regular periods of time: January, April, July and October, radon-222 concentrations have been measured in ten rooms of five elementary schools and in five rooms of one high school at Qena city (Upper Egypt). This has been carried out using alpha scintillation counters. We have noticed that in three rooms the value has exceeded 200 Bqm -3 at the basement and only one room at the first floor, and all values have changed with respect to time and localization: They have decreased from July to January and from basement to first floor. For example, radon-222 concentrations obtained by exposing track detectors varied in the range from 20 Bqm-3 up to 100 Bqm-3. The experimental results of the present work have been well fitted with the presented model (calculations) which supports the validity of the presented model. So, to decrease the level of indoor air radon-222 concentrations and to reduce its harmful effects it is recommended to follow the suggestions in the present study and to limit as possible the use of ceramic in the building construction, increase the hours of ventilation and to restrict the use of underground floors in buildings, the underground Metro and garage parking should be carefully (and even mandatory) ventilated.

Mapping of Radon (²²⁰Rn and ²²²Rn) Concentration Distribution in a Microclimate Condition Cellar Using Nuclear Track Methodology

This work presents the results of the Radon (220Rn and 222Rn) measurements made with 486 chips of CR-39 (Allyl Dyglicol Poly Carbonate) MASL? bared detectors, in a reticular mode distribution, inside of a cellar with average indoor radon concentration 862 ± 49 Bq/m3. The exposure time was 3 months, in microclimate condition of constant temperature, humidity, barometric pressure and no airflow. After these 3 months, all the detectors were chemically etched in KOH 6.25 M solution at 60°C ± 1°C for 18 hours, following a very well established protocol for indoor radon survey by the Dosimetry Applications Laboratory of the Physics Institute of the National Autonomous University of Mexico, and later read automatically by CADIS (Counting Automatically Digital Image System). The results show that each one of the nine measured planes is not homogeneous presenting important differences of indoor radon concentration values. Specifically, the Radon (220Rn and 222Rn) concentration levels vary for each measured point within the cellar. It is a very important observation to consider for the calculation of dose and radiological risk.

Natural Gas and Indoor Air Pollution: A Comparison With Coal Gas and Liquefied Petroleum Gas

Objective The study was designed to compare the combustion products of coal gas, liquefied petroleum gas and natural gas in relation to indoor air pollution. Methods Regular pollutants including B(a)P were monitored and 1-hydroxy pyrene were tested in urine of the enrolled subjects. Radon concentrations and their changes in four seasons were also monitored in the city natural gas from its source plant and transfer stations to final users. To analyze organic components of coal gas, liquefied petroleum gas and natural gas, a high-flow sampling device specially designed was used to collect their combustion products, and semi-volatile organic compounds contained in the particles were detected by gas chromatograph-mass spectrograph (GC/MS). Results Findings in the study showed that the regular indoor air pollutants particles and CO were all above the standard in winter when heating facilities were operated in the city, but they were lowest in kitchens using natural gas; furthermore, although NO2 and CO2 were slightly higher in natural gas, B(a)P concentration was lower in this group and 1-hydroxy pyrene was lowest in urine of the subjects exposed to natural gas. Organic compounds were more complicated in coal gas and liquefied petroleum gas than in natural gas. The concentration of radon in natural gas accounted for less than 1‰ of its effective dose contributing to indoor air pollution in Beijing households. Conclusion Compared to traditional fuels, gases are deemed as clean ones, and natural gas is shown to be cleaner than the other two gases.

室内氡实时监测预警系统设计

针对室内氡实时监测的问题,提出一种基于嵌入式技术、无线通信技术和传感器技术的室内氡实时监测预警系统的设计方案。该系统包括服务器和终端控制器两部分,能够实现对室内氡浓度的远程实时监测与预警。其中,服务器是使用面向对象语言设计的可视化实时监测平台;终端控制器使用STM32芯片作为主控芯片核心,主要实现α粒子数的采集与传输,包含α粒子探测器模块、Wi-Fi无线传输模块、语音预警模块等。服务器和终端控制器使用TCP/IP协议进行通信,终端控制器将当前采集的α粒子数使用特定的数据帧格式,通过无线通信的形式传输给服务器。实验表明,室内氡实时监测预警系统运行稳定,测量精度较高,实时性好。

绵阳市室内空气氡浓度调查

目的:调查绵阳市室内空气氡浓度并分析其影响因素。方法:2020年至2021年在绵阳市各区(市)县城选择居住、办公等场所布点,进行90d的累积空气氡浓度测量,并测量室内、外γ剂量率水平。回收后的氡采集盒交由国家疾控中心辐射安全所统一计算,获得氡浓度数据,单个房间仅有一个采样点时,室内氡浓度为单个氡采集盒测得数据,同一室内测量点大于1个时,取多个测量点读数的平均值。采用单样本t检验和秩和检验分别分析室内外γ辐射水平差异和不同因素对室内空气氡浓度的影响。结果:在绵阳市辖区内126场所放置184个氡采集盒,获得126个场所的室内空气氡浓度数据,氡浓度水平范围37.88~251.00Bq/m^(3),均值为64.34±21.53Bq/m^(3),室内外γ辐射水平差异显著(t=2.847,P=0.006),建筑材料主要为空心砖的房屋室内空气氡浓度要高于以黏土砖为材料的建筑(H=6.932,P=0.031)。结论:绵阳市室内空气氡浓度均未超出国家标准限值(300Bq/m^(3)),但高于邻近地区,并会增加γ射线剂量率;室内通风情况差、使用放射性水平高的建筑材料会增加室内空气氡浓度。