重庆市主城区室内氡浓度调查与评价

根据重庆市城市组团式建设特点,采用径迹法对重庆市主城建成区开展室内氡浓度调查。结果表明,各区县室内氡浓度整体水平较低,重庆市主城区室内氡浓度平均值为64.5 Bq/m3,168个采样点均小于国家标准200 Bq/m3;吸入氡及子体对人员产生的年均有效剂量均低于《住房内氡浓度控制标准》和《地下建筑氡及其子体控制标准规定》中规定的室内氡浓度行动水平。     

某铀矿山废石场及尾砂库氡污染调查

通过对某退役铀矿山的 14个废石堆放场及 3个尾砂库氡析出率的测量及内照射剂量的估算 ,表明 ,只有一个废石场的氡析出率超过国家规定的管理限值水平 ;尾砂库的氡析出率较高 ,个别测点的氡析出率超出管理限值水平近 7倍 ;因氡析出而使当地居民额外所受的年最大有效剂量当量为 0 0 5 8mSv。指出在尾砂库表面覆盖黄土 ,可以有效降低氡析出水平 ,当覆盖厚度达 0 5m时 ,可将氡析出水平降低 84%以上。     

哈密地区环境中氡及其子体浓度所致居民剂量评价

用双滤膜法和Ｔｈｏｍａｓ三段法测定了哈密地区环境空气中氡及其子体浓度．结果表明，室内氡及其子体浓度平均值分别为２８．ＯＢｑ·ｍ－３和７．５×１０－８Ｊ·ｍ－３，室外氡及其子体浓度平均值分别为１０．７Ｂｑ·ｍ－３和３．１×１０－３Ｊ·ｍ－３．氡及其子体所致居民人均有效剂量当量为１．０３ｍＳｖ·ａ－１，集体有效剂量当量为４．２×１０２ｍａｎ·Ｓｖ．     

某铀矿山辐射环境历史演化

调查了某铀矿山居民区环境空气中氡及其子体浓度、空气吸收剂量率和水中放射性核素含量。在已有资料的基础上，对历史时期的辐射环境进行分析。结合实地监测数据，对辐射剂量估算，评价该矿山辐射环境的现状。结果表明，该矿山排放的放射性物质确实对当地的居民产生了一定影响，在所调查的时间段内，该矿山评价区域由放射性物质排放所致关键子区居民的最大年有效剂量为0.52mSv；无论是历史时期还是现状，其关键核素都是^222Rn。指出，为了进一步降低放射性物质对环境的影响，首先应考虑减少^222Rn的排放。     

贵阳室内氡时空分布特征研究

为了全面分析室内氡的时空分布特征、来源和影响因素,选择了贵阳市不同地理位置的居民住宅、办公场所和公共场所,进行了为期一年的室内氡监测。贵阳市室内氡的平均浓度为(72.7±1.6)Bq/m3,低于室内空气污染国家标准,达标率98.5%。其中居民住宅、办公场所和公共场所的室内氡浓度分别为(93.46±86.93)、(74.68±40.74)、(61±26.93)Bq/m3。研究表明,室内涂料、装修程度和通风效果、小区环境等对室内氡浓度高低有显著影响,室内氡也随季节变化而发生波动。对于居民住宅和公共场所氡的室内外来源相对重要性不同。居民住宅内新楼和旧楼不同楼层室内氡的来源、影响因素和分布特征有显著差异。     

广州市新建民用建筑工程土壤氡浓度调查

对广州市天河区和白云区206个新建民用建筑工程场地土壤氡浓度进行了调查.结果表明,不同测点的土壤氡浓度为520 Bq/m3～147 500 Bq/m3,不同工程场地土壤平均氡浓度相差也很大;土壤氡浓度与场地岩性的分布比较吻合.在所测场地中,只有4个工程场地的土壤氡浓度超过周围非地质构造断裂区域3～5倍,需要采取相应的防氡措施,其他须进行一般的建筑工程场地地基施工即可.     

哈密地区建筑材料氡发射系数测定

本文用FD-125型氡钍分析仪以α-射气闪烁法测定了哈密地区建材氡发射系数,其范围值为0～18.7％.氡发射平均系数的高低顺序是土块>普通水泥>花岗石材>红砖>预制构件>沙>石灰.结果表明,建材氡发射系数的高低不仅取决于建材~(226)Ra含量,很大程度上也取决于建材氡发射系数.测定该系数对评价建材所致居民室内氡浓度有一定意义.     

提高土壤氡浓度测定效率的方法

采用测量α粒子能量的方法来确定氡及其子体的浓度,找出测量规律及提高测量效率的方法.通过实验建立了提高土壤中氡浓度的测量效率的模型.     

室内氡子体浓度的动态观测

采用Markov快速潜能法,观测了武汉市某一建筑物室内氡子体浓度随季节和昼夜的变化规律.结果表明:全年(215天)室内氡子体浓度呈正态分布,24小时内最大值与最小值之比为2.9,月均值在年均值±60％内变化.对气压、气温、日照、相对湿度等气象因素的影响也进行了初步探讨.     

环境中氡水平及其对人体健康危害

简介了环境中氡的水平、污染来源、变化规律、对人体的健康危害及防治措施。 并提示，新疆环境中氡的调查研究应引起有关部门的重视，对于氡及子体致癌机理、 多因素的综合 影响及危险估计等都待深入研究以及加紧氡的测量方法的研制。     

Indoor radon measurement and effective dose assessment of 150 apartments in Mashhad,Iran

Environmental monitoring and indoor radon measurement are important for public health, to estimate the cancer risk of respiratory system and, if necessary, to suggest proper methods that reduce indoor radon level. In this research, indoor radon concentration in the air has been measured in 150 apartments in Mashhad city. The result demonstrates about 94.7% of apartments have radon concentration less than 100 Bq/m³, taken by WHO as the action level, and 5.3% have the concentration higher than this level. As well as, annual radon dose has been assessed using the equation for annual effective dose calculation introduced by United Nations Scientific Committee on the Effects of Atomic Radiation.     

地铁振动引起的二次辐射噪声适用标准研究

研究了城市地铁产生的二次辐射噪声测量现状及评价方法,依据现行地铁二次辐射噪声监测相关标准,对城市地铁产生的二次辐射噪声进行测量,将JGJ/T 170—2009、GB 50118—2010和GB/T 50355—2018中规定的限值与地铁二次辐射噪声的特征频谱、环境影响评价以及噪声限值进行了对比分析。结果显示,现行标准限值在执行中存在一定的不完善之处,需要根据实测数据重新分析评价标准的适用性、准确性和合理性。结合当前噪声管理的社会需求,提出了声级增量和特征频谱增量的概念,并将分析结果与现行标准值进行了比较分析,表明声级增量和特征频谱增量能更好地反映二次辐射噪声的影响,对于地铁二次辐射噪声标准的制修订具有参考价值。     

Indoor radon/thoron levels and inhalation doses to some populations in Himachal Pradesh, India

It is well established that some areas of Himachal Pradesh (H.P.) state of India situated in the environs of the Himalayan mountains are relatively rich in uranium-bearing minerals. Some earlier studies by our group have indicated high levels of radon (>200 Bq m(-3)) in the dwellings. It is in this context that an indoor radon/thoron survey has been carried out in selected villages of four districts in the state of H.P. This survey has been conducted as a part of a national, coordinated project using twin chamber dosemeter cups designed by the Environmental Assessment Division (EAD), Department of Atomic Energy, Govt. of India. The track-etch technique is used for calibration of plastic detector LR-115 type-II which are employed for recording alpha tracks due to radon/thoron and their daughters. Year long radon/thoron data have been collected for seasonal correlations of indoor radon/thoron in the dwellings. The indoor radon levels have been found to vary from a minimum value of 17.4 Bq m(-3) to a maximum value of 140.3 Bq m(-3). The indoor thoron levels vary from a minimum value of 5.2 Bq m(-3) to a maximum value of 131.9 Bq m(-3). The year average dose rate for the local population varies from 0.03 microSv h(-1) to 0.83 microSv h(-1). The annual exposure dose to inhabitants in all the dwellings lies below the upper limit of 10 mSv given in ICRP-65.     

Exposure and inhalation risk assessment in an aluminium cast-house

To date the exposure, absorption and respiratory health effects of cast-house workers have not been described since most studies performed in the aluminium industry are focused on exposure and health effects of potroom personnel. In the present study, we assessed the external exposure and the absorbed dose of metals in personnel from the aluminium cast house. This was combined with an evaluation of respiratory complaints and the lung function of the personnel. 30 workers from an aluminium casting plant participated and 17 individuals of the packaging and distribution departments were selected as controls. The exposure was assessed by the quantification of total inhalable fume with metal fraction and by the determination of urinary aluminium, chromium, beryllium, manganese and lead concentration. Carbon monoxide (CO), carbon dioxide (CO2), aldehydes and polyaromatic hydrocarbons and man-made mineral fibres concentration were assessed as well. In order to evaluate their respiratory status each participant filled out a questionnaire and their lung function was tested by forced spirometry. Total inhalable fume exposure was maximum 4.37 mg m(-3). Exposure to the combustion gases, man-made mineral fibres and metal fume was well below the exposure limits. Beryllium could not be detected in the urine. The values of aluminium, manganese and lead in the urine were all under the respective reference value. One individual had a urinary chromium excretion above the ACGIH defined biological exposure index (BEI) of 30 microg g(-1) creatinine. There was no significant difference in any of the categories of the respiratory questionnaire and in the results of the spirometry between cast house personnel and referents (Chi-square, all p > 0.05). Exposure in cast houses seem to be acceptable under these conditions. However, peak exposure to fumes cannot be excluded and the potential risk of chromium and beryllium exposure due to the recycling of aluminium requires further attention.     

Atmospheric dispersion of radon gas and its decay products under stable conditions in arid regions of Australia

The radon and radon daughter concentration-in-air from natural background are assessed along with the micrometeorology and synoptic weather systems in an arid region of Australia. The radon daughter contribution to population dose is biased towards the frequency of nocturnal inversions. Classical atmospheric models are not applicable during stable atmospheric conditions in inland Australia. An atmospheric Box Model is used along with measured data from tethersonde profiles in predicting radon/radon daughter concentration-in-air. Predicted and measured concentrations are compared for spatial and temporal variations.     

Periodicities of the radon level in Butte,Montana

Hourly measurements of radon level at four houses in Butte, Montana were analyzed. Previous studies suggestes that there are diurnal cycles, spectral analysis confirms this assertion. Moreover, there are also long term trends and weekly cycles at certain locations. The periodical cycles highly suggest that indoor radon level can be dependent on the ventilation condition of the house and the activities of the residents.The relationship of indoor and outdoor radon level was investigated by cross-spectral analysis. In view of the possible different patterns caused by different seasons, data from the winter and summer are analyzed separately. The results shows that winter and summer data do display different patterns.     

Biological monitoring of wood dust exposure in nasal lavage by high-performance liquid chromatography

A high-performance liquid chromatography (HPLC) method for biomonitoring of occupational wood dust exposure based on nasal lavage as a biomonitoring matrix was developed. Gallic acid (GA) was chosen as the indicator compound for oak dust exposure. From the chromatographic profile of ash dust, four peaks were chosen as indicator compounds. Phenolic indicator compounds were analysed by HPLC. Personal dust samples and corresponding nasal lavage samples were collected from 16 workers exposed to oak dust and six to ash dust. The dust concentrations in the workers' breathing zone varied between 0.7 and 13.8 mg m(-3). The indicators revealed the nature of the wood dust inhaled. For the workers who did not use respirators, the correlation between the dust and corresponding indicator compound in their nasal lavage was significant; r2 = 0.59 (n = 12) for oak dust and r2 = 0.58 (n = 6) for ash dust, respectively. Further, the correlation for oak dust workers who used respirators was r = 0.67 (n = 4). Nasal lavage sampling and HPLC analysis of polyphenol indicator compounds are promising tools for measuring wood dust exposure. Although further validation is necessary, determination of the individual dose may prove invaluable in prospective epidemiological studies.     

Investigation of indoor environmental quality in Shanghai metro stations, China

A field study was carried out in Shanghai metro stations to gather and evaluate information about the real environment. The thermal environment and particulate matter levels were monitored in this study. The mean thermal sensation vote in metro stations was 0.91, and the mean thermal neutral temperature was 20.6°C. Although 92.1% of subjects voted that the thermal environment was acceptable, the condition of air quality in Shanghai metro stations was not good. The mean levels of PM1.0, PM2.5, and PM10 were 0.231 ± 0.152, 0.287 ± 0.177, and 0.366 ± 0.193 mg/m³, respectively. The contribution of PM1.0 to PM2.5 and PM2.5 to PM10 was up to 79% and 76%, respectively. This means that fine particles or ultrafine particles constituted the preponderant part of metro station particulate matter.     

Outdoor 220Rn, 222Rn and terrestrial gamma radiation levels: investigation study in the thorium rich Fen Complex, Norway

The present study was done in the Fen Complex, a Norwegian area rich in naturally occurring radionuclides, especially in thorium ((232)Th). Measurement of radioactivity levels was conducted at the decommissioned iron (Fe) and niobium (Nb) mining sites (TENORM) as well as at the undisturbed wooded sites (NORM), all open for free public access. The soil activity concentrations of (232)Th (3280-8395 Bq kg(-1)) were significantly higher than the world and the Norwegian average values and exceeded the Norwegian screening level (1000 Bq kg(-1)) for radioactive waste, while radium ((226)Ra) was present at slightly elevated levels (89-171 Bq kg(-1)). Terrestrial gamma dose rates were also elevated, ranging 2.6-4.4 μGy h(-1). Based on long-term surveys, the air concentrations of thoron ((220)Rn) and radon ((222)Rn) reached 1786 and 82 Bq m(-3), respectively. Seasonal variation in the outdoor gamma dose rates and Rn concentrations was confirmed. Correlation analyses showed a linear relationship between air radiation levels and the abundance of (232)Th in soil. The annual outdoor effective radiation doses for humans (occupancy 5 h day(-1)) were estimated to be in the range of 3.0-7.7 mSv, comparable or higher than the total average (summarized indoor and outdoor) exposure dose for the Norwegian population (2.9 mSv year(-1)). On the basis of all obtained results, this Norwegian area should be considered as enhanced natural radiation area (ENRA).