Radon

activity is determined by gamma spectrometry, based on the measurement of radon progeny short lived isotopes ( 214 Pb and 214 Bi) when Ra-Rn secular equilibrium is reached. Depending on the behaviors of radon emanation from the soil matrix, the homogeneous distribution of these radionuclides in measured soil samples may be lost, which may affect the quality of the obtained results if not taken into consideration. This paper highlights some assumptions regarding the distribution of radon daughters in the soil matrix and their effect on the detection efficiency of an HPGe detector using Mont Carlo simulation code.

In the period July 2005 -October 2006 several soil gas prospections were performed on the island of Pantelleria, an active volcanic/geothermal system at present in a quiescent state. Measured parameters were CO2 concentrations and 220 Rn and 222 Rn activities at 50 cm depth and CO2 fluxes from the soil. The whole island was covered with a measurement density of 3.5 points/km 2 for CO2 (flux and concentration) and 1.6 points/km 2 for Rn. Further three main and seven minor areas of previously ascertained or expected exhalative activity were covered with a measurement density up to 100 points/km 2 . The obtained results ranged from 0.038 to 95%vol for CO2 concentration, from 10 Bq/m 3 to 164,000 Bq/m 3 from 10 Bq/m 3 to 750,000 Bq/m 3 for 220 Rn and 222 Rn activities, respectively and from < 0.1 to 4700 g/m 2 day for CO2 fluxes. Probability plots evidenced for all measured parameters the presence of three populations (background, mixed and hydrothermal). All anomalous values were found in the central part of the island within the youngest caldera. Flux data allowed us to estimate a total CO2 output of the volcanic/geothermal system of Pantelleria in 24.2 tons per day. Some new exhaling area, significantly contributing to the total output and characterised by stunted or absent vegetation, were evidenced on the southern flank of Mt. Grande. At one of these areas the relationships between the measured parameters and vegetation cover were studied in detail along a 140m long transect of 15 points. Finally, a first evaluation of the gas hazard related to the geogenic degassing evidenced some high risk area at the mofette along the shores of the Lake Specchio di Venere (CO2) and in the village of Rekale (CO2 and Rn).

Radon gas has high mobility and is driven by advection and diffusion with the soil gas throughout connected and water-unsaturated pores and/or cracks in permeable rocks and soils. Therefore, there is a need for quantitative assessment of the saturation state, even on a daily-base in order to estimate the radon potential correctly. The more so as, the permeability is one of the key factors in the radon risk assessment. For the purpose of such investigation, a vertical profile model was elaborated for a study site in Northeast Bulgaria. On the base of pedotransfer function analyses, the hydraulic parameters describing the retention function and the hydraulic conductivity function were determined for each case study. The results show that even in a month with high amount of rainfall precipitation (13% of the total amount per year), the loess profile at certain depths remains unsaturated, regardless the difference in the hydraulic characteristics.

The study deals with pilot investigations of the radon index in Bulgaria. In situ measurements of the radon activity and soil permeability at 3 sites one over and two – close to fault zone have been performed. The results show that higher radon content is detected in the fault zone.

Natural radon (222Rn) is a radioactive noble gas that occurs as the immediate decay product of radium (226Ra), part of the 238U family, in the lithosphere. Radon is driven by advection and diffusion with soil gas throughout connected and water-unsaturated pores and/or cracks in permeable rocks and soils. The aim of the present study is to do a review of the existing so far research activities in Bulgaria in connection with the observation and/or evaluation of the degree of water saturation of the near-surface layer, and on that base to distinguish the up-to-date achievements in regards to the radon potential in situ evaluation. Due to this review, the studies in Bulgaria concerning moisture dynamics in the near-surface layers can be divided mainly into two groups. The first one investigates the hydraulic characteristics (parameters) of soils in the vadose zone. Based on that, conclusions or computer simulations for the saturation degree estimation can be drawn. The other group inclu...

Introduction DNA repair enzymes could modulate the individual susceptibility to the genotoxic effect of exposure to ionising radiation (IR). Methods The influence of polymorphisms of XRCC1, XRCC3 and XPD genes on the onset of chromosomal and DNA damage has been investigated in 43 workers exposed to low levels of IR, including 36 healthcare professionals and 7 industrial radiologists (exposed workers), and 43 subjects not occupationally exposed to IR (controls), matched for age. Chromosomal aberrations (CA) and micronuclei (MN) frequencies in peripheral blood lymphocytes were measured according to standard procedures and used as cytogenetic biomarkers, while Tail Intensity (TI) was the parameter of the Comet test used to evaluate oxidative DNA damage. Genotypic variants Arg194Trp, Arg280His and Arg399Gln for XRCC1, Thr241Met for XRCC3 and Lys751Gln for the XPD genes were analysed using the restriction fragment length polymorphism technique. Results Both total CA and chromosome breaks frequencies were significantly higher in the exposed workers than controls (p<0.05 and p<0.01 respectively), while no significant differences between the two groups were observed in terms of chromatid breaks and MN frequencies as well as the TI. In the controls only, TI was significantly higher in females than males, whereas a smoking habit did not affect the biomarkers investigated. The genetic polymorphisms of XRCC1, XRCC3 and XPD, individually analysed, did not influence any of the genotoxicity and oxidative damage biomarkers studied, either in the exposed workers or the controls. Discussion Chromosome breaks frequency resulted a valid cytogenetic biomarker for the monitoring of workers exposed to low doses of IR. The presence of single genetic variants reducing the activity of DNA repair enzymes does not seem to determine an increased risk of genotoxic effects of low doses of IR.

The aim of the study was to assess the effect of residential radon exposure on the risk of lung cancer in never-smokers and to ascertain if environmental tobacco smoke modifies the effect of residential radon. We designed a multicentre hospital-based case-control study in a radon-prone area (Galicia, Spain). All participants were never-smokers. Cases had an anatomopathologically confirmed primary lung cancer and controls were recruited from individuals undergoing minor, non-oncological surgery. Residential radon was measured using alpha track detectors. We included 521 individuals, 192 cases and 329 controls, 21% were males. We observed an odds ratio of 2.42 (95% CI 1.45-4.06) for individuals exposed to ≥200 Bq·m(-3) compared with those exposed to &lt;100 Bq·m(-3). Environmental tobacco smoke exposure at home increased lung cancer risk in individuals with radon exposure&gt;200 Bq·m(-3). Individuals exposed to environmental tobacco smoke and to radon concentrations&gt;200 Bq·m(-3) ha...

According to the Environmental Protection Agency (EPA) and other public health agencies in the United States, radon may be the leading cause (along with passive smoking) of lung cancer deaths among nonsmokers. Radon is estimated w be the second leading cause of lung cancer death in smokers behind smoking-related lung cancer. EPA estimates that 7,000 to 30,000 lung cancer deaths each year are due w radon exposure. (It is implied that radon-related lung cancer deaths can be prevented by reducing radon levels below EPA'S guideline levels.) Current EPA radon policy is based on a strategy of education, the transfer of testing and remediatwn technologies to the public and private sectors, and recently proposed radon-resistant construction standards for new homes. This paper models the effectiveness of current, proposed, and alternative policies for reducing radon niks in U S . residential construction. The results of our analysis suggest that EPA's pmjectwns of 2,200 "lives saved annually" as a result of its current action level of 4 pCill will not be achieved with its current policy in the near future. Overall, the response of radon-related mortality w most policy options is delayed and flat due in part to the large number of houses with low radon levels and the long latency period between radon exposure and the development of cancer. The modeling results suggest that more aggressive smoking reduction programs may yield greater benefits in overall lung cancer mortality (but not reduced radon exposure) than most radon-related policies.

According to the Environmental Protection Agency (EPA) and other public health agencies in the United States, radon may be the leading cause (along with passive smoking) of lung cancer deaths among nonsmokers. Radon is estimated w be the second leading cause of lung cancer death in smokers behind smoking-related lung cancer. EPA estimates that 7,000 to 30,000 lung cancer deaths each year are due w radon exposure. (It is implied that radon-related lung cancer deaths can be prevented by reducing radon levels below EPA'S guideline levels.) Current EPA radon policy is based on a strategy of education, the transfer of testing and remediatwn technologies to the public and private sectors, and recently proposed radon-resistant construction standards for new homes. This paper models the effectiveness of current, proposed, and alternative policies for reducing radon niks in U S . residential construction. The results of our analysis suggest that EPA's pmjectwns of 2,200 "lives saved annually" as a result of its current action level of 4 pCill will not be achieved with its current policy in the near future. Overall, the response of radon-related mortality w most policy options is delayed and flat due in part to the large number of houses with low radon levels and the long latency period between radon exposure and the development of cancer. The modeling results suggest that more aggressive smoking reduction programs may yield greater benefits in overall lung cancer mortality (but not reduced radon exposure) than most radon-related policies.

The long–term measurements of radon and thoron equilibrium equivalent concentrations (EERC and EETC) were carried out the first time in Republic of Srpska in 25 schools of its capital Banja Luka and in its wider surroundings. After this successful survey, the measurements continued using the same type of the LR 115 nuclear track detectors, i.e., Direct Radon Progeny Sensors/Direct Thoron Progeny Sensors (DRPS/DTPS), and they were deployed in the 36 dwellings nearby the investigated schools. The detectors were exposed for one year period at 15–20 cm distance from the walls. The EERC and EETC were found to vary in the range from 6.3 to 14.4 Bq/m3and from 0.10 to 1.1 Bq/m3, with geometric mean 9.3 and 0.36, respectively. The same variance of EER and EET concentrations, measured in living and bedrooms of buildings built with different construction materials as well at different floors have been obtained. The insignificant correlations between EERC and EETC, show that these concentration...

The study deals with the evaluation of the dynamic of the radon index in one pilot site based on second-time pilot investigations of the radon index in Bulgaria. In situ measurements of the radon concentration in soil gas, and soil permeability at three polygons: one over and two – close to fault zone have been performed in October 2020 and October 2022. The results show that higher radon content is detected in the fault zone in both cases.

The indoor radon concentrations in Kirklareli, Turkey were measured in living rooms of 19 houses during winter in 2019 using Airthings 222 Corentium Home Radon Gas Detector. The short-term and long-term measurements were performed in 1 and 7 days for each house to investigate radioactive radon gas exposure in Kirklareli buildings. The indoor radon concentrations were varied from 23 to 156 Bq m-3 for 1 day period and were varied from 16 to 77 Bq m-3 for 7 days period. The average radon gas concentration was found as 43.5 Bq m-3 and this result is higher than the average of Turkey and the world average. The annual effective doses due to radon gas exposure were also estimated. The annual effective dose rate ranged from 0.61 to 2.94 mSv y-1 with a mean value of 1.09 mSv y-1.

Indonesia merupakan Negara Kepulauan yang berada di jalur Ring Of Fire kawasan Pasifik yang sering terjadi gempa bumi.   Oleh karena itu dindinggeserdapatdigunkansebagaisalahsatu alternative untukmengurangipengaruhgempaterhadapstrukturbangunangedung.Perbedaan rasio tinggi dan lebar dinding akan menunjukkan perbedaan perilaku masing – masing dinding.  Penelitian ini bertujuan untuk mengetahui pengaruh aspek rasio tinggi dan lebar pada dinding geser terhadap momen kapasitas dan pola retak dengan pembebanan siklik. Terdapat 2 variasi dinding geser, yaitu dinding geser dengan tulangan horizontal single dan dinding geser dengan tulangan horizontal double .  Dinding geser diberi beban aksial konstan sebesar 3000 kg,kemudian diberi beban lateral pada ketinggian 0,6 m hingga mencapai drift yang telah dilakukan.Hasil pengujian menunjukkan bahwa dinding  geser yang sama (SD-150) dengan aspek rasio yang berbeda (1,5 dan 2) menghasilkan momen yang cenderung sama.Akan tetapi dengan aspek rasio l...

The purpose of the article is to describe monitoring studies on the radiation state of air in populated and working areas near the uranium processing enterprise in the Republic of Uzbekistan. Ac-cording to the analytical measurement, the exposure dose of gamma radiation is equivalent to the equilibrium volume activity of radon, specific activity of long-lived alpha-emitting nuclides in the zone of influence of the enterprise, the working area, premises for storing uranium materials and manufacturing dumps, tailings dams and areas of underground uranium leaching. It was shown that the measurement results do not exceed the regional background and regulatory levels of radioactive radiation by all indicators. The dependence of the volume activity of radon at production facilities on the density of the radon flux from the soil was studied. The most intensive radioactive objects – uranium dumps – were identified. It was found out that there is no excess radioactive impact of the uranium e...

Fractional Radon transform which is symbolized with the notation , it is different to the classical Radon transform. The shift property of fractional Radon transform is controlled by the fractional order Rotation of the input object at angle  will rotate the fractional Radon transform at that angle thus, the fractional Radon transform is rotation invariant. The fractional Fourier transform, with respect to  of the fractional Radon transform of an object is the central slice at angle  of the -dimensional fractional Fourier transform of this object. In this paper we explain the mathematical formation of fractional Radon transform and established a convolution theorem for the fractional Radon transform.

Simultaneous indoor measurements of radon, thoron and equilibrium equivalent con centrations, by three different continuous radon monitors in real ambient conditions, were performed and compared during two weeks period. Radon concentrations varied from 153 Bqm?3 to 870 Bqm?3 with variations of thoron concentrations in the range (2.17-219) Bqm?3. Obtained arithmetic means of equilibrium equivalent radon and thoron concentrations were (130 ? 50) Bqm?3 and (23 ? 18) Bqm?3, respectively. The inter-comparison of active radon de vices was focused on consistency of results between them selves and the influence of environmental conditions on the behavior of each detector system. The obtained statistically significant correlation between the results of used monitors, validates them for application in radon diagnostic measurements as the first step in radon remediation and dose assessment.

Aim of a low radon cleanroom technology is to minimize at the same time radon, radon decay products concentration and aerosol concentration and to minimize deposition of radon decay products on the surfaces. The technology placed in a deep underground laboratory such as LSM Modane with suppressed muon flux and shielded against external gamma radiation and neutrons provides “Zero dose” space for basic research in radiobiology (validity of the LNT hypothesis for very low doses) and for the fabrication of nanoelectronic circuits to avoid undesirable “single event effects.” Two prototypes of a low radon cleanroom were built with the aim to achieve radon concentration lower than 100 mBq·m3 in an interior space where only radon-free air is delivered into the cleanroom technology from a radon trapping facility. The first prototype, built in the laboratory of SÚRO Prague, is equipped with a standard filter-ventilation system on the top of the cleanroom with improved leakproofness. In an exp...

The Jacobi room model, describing the behaviour of free and attached radon progeny in the atmosphere of a room was introduced by W. Jacobi 37 years ago [1], was worked out and broadly applied in indoor measuring by J. Porstendorfer [4, 5]. It has been successfully used up to now without substantial changes, so designating it as the J-P model is justified. There have been several attempts to invert measured data to determine the parameters describing the physical processes by approximate approaches [2, 3]. Here, an exact solution is given.

In this paper, we will deal with interesting example of natural risk modeling – namely of indoor radon concentration, needed for proper exposure assessment and appreciation of quality of preventive measures taken. First, we will illustrate, how the traditional view based on fixed (i.e., time‐invariant) coefficient models can be misleading. Then we formulate a flexible (nonparametric) regression dynamic model offering a doable alternative. Situation is not entirely standard here, as the smoothed and weight‐giving variables are different. Nevertheless, estimation for our local regression formulation is easily doable even for rather large data via extension of standard local smoothing that we describe. We illustrate on data coming from a rare intensive measurement campaign in an occupied house with simultaneous measurements taken in different rooms. Our model has nice physical interpretation of its parts. We also illustrate how even such a simple model can produce behavior that throws ...

Four years of summertime paired urban‐rural meteorological and radon observations in central Poland are used to assess the relationship between atmospheric stability and urban‐induced changes to the radiation balance and surface energy budget. An existing radon‐based technique for nocturnal stability classification is improved and extended to also infer daytime mixing conditions. The radon‐based scheme is shown to provide a simple, effective, objective means of investigating urban energy budget closure over a range of meteorological conditions, which promises to improve estimates of energy storage and loss terms associated with urban canopies. Special attention is paid to quantifying atmospheric characteristics associated with the arbitrarily assigned radon‐derived stability categories in terms of the more conventional measures: bulk Richardson number and the Monin‐Obukhov stability parameter (z/L). The bulk Richardson number approach is demonstrated to be less effective at grouping...

Development of a multichannel radiometer consisting of three radiometers based on highly sensitive silicon detectors for environmental studies, recording and studying the activities of alpha, beta and gamma radiation in various environments. Three types of detectors were manufactured for the three radiometers. In the radiometer, lithium drift detectors were used to measure the activity of gamma radiation; to measure the activity of beta particles and the volumetric activity of radon, heterojunction or surface-barrier detectors were installed in the radiometers. The structure of the device and the electrical circuit have been developed. The manufactured detectors had low losses on the "input" and "output" windows, which made it possible to carry out measurements on both sides. The structure of the device using these detectors and the developed electrical circuit of the microcontroller node and nodes for amplifying and selecting information of the microcontroller node are presented. Monitoring data for gamma and beta radiation activities and volumetric radon activity are presented. The results showed the dependence of the volumetric activity of radon on humidity. Beta radiation activity did not show any dependence on humidity, but there was a sharp increase on certain days.

Electrostatic precipitation is a well-known technology to reduce public exposure to radon daughters. A custom electrostatic precipitator (ESP) prototype has been designed and built to study the effectiveness of such a removal technique in specific workplaces having low-to-zero air exchange rates with external environments. An appropriate mathematical model has been set up in order to simulate the behavior of environmental and nuclear data throughout the ESP operation, to optimize the design for the prototype to be built, to estimate its effectiveness in terms of effective dose reduction. Reference detectors have been used to measure both the radon concentration and the potential alpha energy concentration of its decay products. After a full calibration procedure, two main experiments have been performed in a room satisfying the requirements of very low ventilation rate and high radon concentration. The effective dose rate after an ESP continuous working period of either 3 h or 5 h turned out to be 50% lower than the value measured before ESP switching ON. The main contribution to dose reduction was found to be given by the first 2 hours of operation.

An important achievement of nuclear track detectors is that they render it possible to measure a large number of radon concentrations. These are necessary for epidemiological studies aimed to estimate the lung cancer risk due to exposure to radon and its decay products in dwellings. Many case-control studies were conducted in the last 15 years in Europe, North America and China, in order to avoid the uncertainties associated with the risk extrapolation from epidemiological studies on miners exposed in underground mines. In this review paper, the main methodological issues of these studies are introduced: confounding factors, the impact of radon exposure uncertainties on the estimated risk, the retrospective assessment of radon exposure through the measurement of 210 Po surface concentration on glass objects, the interaction between radon and smoking, statistical methods to analyze data and combine studies, etc. As regards the estimated risk of lung cancer, the main characteristics and results of each study are reported and discussed, together with the results of meta-analyses and, most importantly, of the three recently published analyses that pool 2 Chinese, 7 North American, and 13 European studies. Finally, some conclusions are given and a brief reference is made to ongoing studies.

The health risk due to the presence of thoron indoors is usually neglected because of its generally low concentration in indoor environments, which is essentially caused by its short half-life. However, in certain not uncommon situations, such as when thorium-rich building materials are used, thoron ( 220 Rn) may represent a significant source of radioactive exposure. In recent years, renewed interest has led to more intensive monitoring of thoron gas and its decay products. A tentatively comprehensive summary of these measurement results and a review of the most innovative measurement techniques for 220 Rn are here presented. Finally, dose-exposure conversion factors currently used for thoron decay products are analysed, highlighting the poorer basis of such factors, when compared to those for radon.

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For workplaces where significant diurnal variations in radon concentrations are likely, measurements to evaluate average radon concentration during working hours could be useful for planning an optimized protection of workers according to the 2013/59/Euratom Directive. However, very few studies on this subject, generally limited to periods of few weeks, have been published. Therefore, a study has been conducted to evaluate the actual long-term radon exposure during working hours for a sample of 33 workplaces of four different types (postal offices, shops, restaurants, municipal offices), mainly located at the ground floor, and with expected considerable air exchange rate occurring during working hours due to frequent entrance/exit of persons or mechanical ventilation. The results show that the difference between the average radon level during working hours and that one during the whole day is about 20% on average and ranges from 0 to 50%. These observed differences, generally smalle...

The estimation of the indoor radon exposure of the population of a country is generally carried out by the means of surveys designed in order to have sample representativeness as a target (population-based survey). However, the estimates of radon concentration distributions could be affected by biases if sampling was not random or in case of differences between sample and target population characteristics. In this work, we performed a preliminary check of the representativeness of the sample used for the second Italian national survey aimed to evaluate radon concentration distribution in each Province. We found that sampled dwellings are mostly located in the main administrative centres, where average radon concentration is generally lower, as compared with the other towns of the Province. The potential source of bias identified in this work suggests to carefully control the occurrence of a sampling imbalance between ‘main’ cities and other cities of Province and to take it into acc...

Outdoor radon concentration contributes to indoor radon levels, generally causing a shift from lognormal distribution of measured radon concentration data distribution, and it makes more challenging the estimation of radon distribution parameters on the basis of the lognormal assumption. In particular, lognormal assumption with no correction could lead to a significantly biased estimate of the percentage of dwellings exceeding a certain level, e.g. a reference level (RL), since this is based on biased estimates of geometric mean (GM) and geometric standard deviation (GSD) of radon concentration distribution. Subtracting to each measured data a constant outdoor radon level can usually compensate data distribution departure from log-normality (except for low radon levels), if the appropriate outdoor level value is chosen by means of a lognormal fit of the data. This approachalready (but not always) used in literaturecannot be applied in cases where all the data of radon concentrations are not available (e.g., for a review study). For these cases, this work presents an analytical method to quantitatively evaluate and correct the impact of outdoor on the lognormal distribution parameter estimates and, in particular, on the percentages of dwellings exceeding radon reference levels. The proposed method is applied to a number of possible situations, with different values of outdoor radon level, GM and GSD. The results show that outdoor radon levels generally produce an underestimation of the actual GSD parameter, which increases as the outdoor level increases, and in the worse cases, could lead to an underestimation higher than 50%. Consequently, if the outdoor contribution is not properly taken into account, the percentage of dwellings exceeding a certain RL is almost always underestimated, even by 80%-90% for RL equal to 300 Bq/m 3 . This could have implications for the classification of areas as regards radon concentration and for the estimation of avertable lung cancers attributable to radon levels higher than some possible RLs.