Radon Concentration Measurements Research Articles

Substantiation of methodical approaches to the control of indoor radon concentration in existing public buildings with non-round-the-clock stay of people

According to the analysis of requests for methodological assistance to the Saint-Petersburg Research In ­stitute of Radiation Hygiene after Professor P. V. Ramzaev, measurements of radon concentration (or radon EEC) in existing operated public buildings (primarily children institutions) in the framework of surveillance actions in the regions of the Russian Federation, as a rule, are taken according to Guidelines MU 2.6.1.2838-11, intended for radiation control of public buildings only when they are put into operation after construction, major repairs or reconstruction, due to the absence of special guidelines. Compliance with the requirements of paragraph 6.5 of MU 2.6.1.2838-11 means that the building and premises are in a state that is not equal to their normal operation mode. Registration of high values of indoor radon concentration in this case leads to management decisions, including administrative suspension o f activities for up to ninety days, i.e. the closure of individual premises or even the entire building of a children institution. The consequences of making such decisions may include an increase in social tension in society and provoking radiophobia among the population. The paper presents specific recommendations for the radon survey for existing operated public buildings with non-round-the-clock stay of people, which are based on the results of the analysis of the experience of practical application of various methods of measuring indoor radon concentrations in such buildings in order to assess average radon concentration during working hours in the normal operation mode. The proposed approach can be further used as the basis for developing special guidelines for radiation control of existing operated public buildings with non-round-the-clock stay of people.

New metrology for radon at the environmental level

Radon gas is the largest source of public exposure to naturally occurring radioactivity. However, radon is also a useful tracer for understanding atmospheric processes, assessing the accuracy of chemical transport models, and enabling integrated emissions estimates of greenhouse gases. A sound metrological system for low level atmospheric radon observations is therefore needed for the benefit of the atmospheric, climate and radiation protection research communities. To this end, here we present a new calibration method for activity concentrations below 20 Bq m−3 and a prototype of the first portable radon monitor capable of achieving uncertainties of 5% (at k = 2) at these concentrations. Compliance checking of policy-driven regulations regarding greenhouse gas (GHG) emissions is an essential component of climate change mitigation efforts. Independent, reliable ‘top down’ methods that can be applied consistently for estimating local- to regional-scale GHG emissions (such as the radon tracer method (RTM)) are an essential part of this process. The RTM relies upon observed radon and GHG concentrations and measured or modeled radon fluxes. Reliable radon flux maps could also significantly aid EU member states comply with European COUNCIL DIRECTIVE 2013/59/EURATOM. This article also introduces the traceRadon project, key aims of which include outlining a standardized approach for application of the RTM, creating infrastructure with a traceability chain for radon concentration and radon flux measurements, and developing tools for the validation of radon flux models. Since radon progeny dominate the terrestrial gamma dose rate, the planned traceRadon activities are also expected to improve the sensitivity of radiation protection early warning networks because of the correlation known to exist between radon flux and ambient equivalent dose rates.

Control of the Health Risk of Radon Exposure in the Republic of Moldova

The paper presents the results of a national radon survey conducted in the context of the Republic of Moldova. The study included about 2500 homes of different types, located in urban and rural localities in different areas of the country. The RADTRAK2 detectors kindly provided by the RADONOVA laboratory, Uppsala, Sweden, for the MOL9007 project funded by the International Atomic Energy Agency (IAEA) have been used. The exposure period was 90 days. The measured radon concentrations are the following: the average (±standard deviation) 252.8 ± 215.9 Bq/m3; the range (minimum–maximum) 10–1480 Bq/m3; the median 200 Bq/m3 and the geometric mean (± geometric standard deviation) 158.5 ± 3.0 Bq/m3. The results of the study allowed mapping indoor radon and identifying localities with increased radon concentrations. In order to reduce the high radon concentrations in places recording >300 Bq/m3, appropriate measures have been proposed according to the legislation in force. The cluster analysis showed positive links between the radon concentration in dwellings and the incidence of respiratory diseases, especially the bronchopulmonary cancer in the country.

Upgrade of a Highly Sensitive Monitor for Atmospheric Radon Measurement

Atmospheric radon is an ideal tracer that is widely used in atmospheric science. To meet the need fora continuous online measurement of atmospheric radon concentration, an upgraded radon monitor based on an electrostatic collection method was developed following Iida’s measurement system. Two major improvements have been realized. First, an 18 mm × 18 mm Si-PIN detector and a multi-channel analysis system were used to distinguish different alpha particles. Second, the P2O5 desiccant was replaced by a new membrane drying system, and the influence of humidity was corrected by a humidity correction coefficient. Calibration and comparison experiments were carried out in detail, and a one-year continuous measurement was also performed. Results showed that the measurement sensitivity was evaluated to be 24.3 cph/(Bq·m−3), and the lower level detection limit was 0.2 Bq·m−3 for a 1-h cycle at the absolute humidity of 0.34 g·m−3. The annual average radon concentration of Beijing was 11.1 ± 4.0 Bq·m−3, which changed from 2.8 Bq·m−3 to 30.3 Bq·m−3 between 15 October 2018 and 1 October 2019. The upgraded monitor’s high data acquisition rate and good performance indicate that it is suitable for long-term observation on atmospheric radon.

A Comparative Study on Indoor Radon Levels between the Lung Cancer and Cancer Free Groups in Izmir Province, Turkey

Purpose: İzmir is the province of Turkey with the highest lung cancer incidences for males, therefore a comparative study was performed in particular districts of İzmir in 2013. In the study, it was aimed to assess the association between lung cancer risk and indoor radon. 
 Methods: Patients diagnosed with lung cancer between 2010 and 2011 were selected from the database of the Izmir Cancer Registry (ICR). Measurements of indoor radon concentrations were performed in a total of 117 locations using the SSNTD (Solid State Nuclear Track Detectors) method with LR-115 detectors. Indoor radon concentration measured in homes of patients with lung cancer and cancer free group were compared statistically. 
 Results: The indoor Radon (222Rn) activity concentration detected ranged from 165 to 487 Bq/m3, for the lung cancer group, from 28 to 367 Bq/m3 for the cancer free group, with geometric means of 269 Bq/m3 and 123 Bq/m3, respectively.
 Conclusion: According to the logistic regression model, as radon concentration and package/year increased, the rate of cancer increased multiple folds. These results suggest that indoor radon levels may contribute to higher rates of lung cancer for İzmir compared to the rest of the country, and indoor radon levels may be a contributory factor in this phenomenon.

Spatiotemporal Variations of Radon Concentration in the Atmosphere of Zhijindong Cave (China)

Ensuring high air quality in the atmosphere of Zhijindong Cave is essential, for it is one of the most scenic in Asia and has received millions of tourists each year. Radon, as the most important radioactive carcinogen, is a priority and has been measured since just after its opening. However, an artificial exit was opened in 2002, and it is still unclear what the influence of that has been on the radon concentration in the cave atmosphere. In this study, we use RAD7 to monitor the spatiotemporal variations of radon concentration in the atmosphere of Zhijindong Cave for a whole year. The results show that radon concentration is generally higher in the hot season and lower in the cold season, and both with a distinct spatial differences. The highest measured radon concentration is 1691 Bq/m3, which is lower compared with the previous study. The reduced radon concentration could be caused by the strengthened cave ventilation due to the artificial exit. The temporal variation of radon concentration is related to the outside temperature change, while the spatial variation is mostly related to the different cave layers. The effective dose is negligible for tourists, but can be as high as 9.7 mSv for tour guides and 22.6 mSv for photographers.

Estimation of radon excess lung cancer near some dumpsites in, Lagos, Nigeria

Generally, in Nigeria dumpsites are open and elevate the pollution by increasing the total environment contamination level. This affects not only the site of dumpsites but also the surrounding buildings and area. In the present work, indoor radon activity concentration is tested inside some buildings in the vicinity of dumpsites in Lagos, Nigeria. A passive technique with CR-39 detectors is used. Different buildings around different eight dumpsites were chosen. Radon concentration had ranged from 16.00 ± 3 to 931.00 ± 186 Bqm−3 in the dumpsites. With Mean concentrations range from 120 ± 24 at OKE-ODO to 334 ± 67, at Solus-4 respectively. The present results explain that 63% of the radon activity concentration in indoor air around the selected dumpsites at Lagos city in Nigeria is below the allowed limit from ICRP 200 Bq m-3 while 37% is more than this limit. Based on the measured radon concentration, the annual effective dose and cancer risk are evaluated. The range of ELC is from 242 to 14086 with mean value 3114 ± 1111.

My Forays Into Interdisciplinary Areas of Research

This article discusses my journey in interdisciplinary areas of research in India as a pioneer. I was trained as a High Energy Nuclear Physicist at Marie Curie University, Paris, but on return to India, I had to train myself in many diverse fields due to lack of experimental facilities in my own field. My first foray was in Geochronology using fission track dating. Then, I got the opportunity to use heavy ion beams available at GSI, Darmstadt, Germany to irradiate polymers, glasses, and mineral samples for the study of radiation damage. Modgil-Virk Single Activation Energy Model is a consequence of our investigations into the annealing characteristics of heavy ion tracks in materials. The most important route was our Radon concentration measurements in indoor air, soil, and groundwater for estimation of health hazard effects and earthquake prediction in the Himalayas. After retirement, I ventured into the area of nanotechnology and fabricated nanocrystals, nanowires, quantum dots, and nanoflowers to study their properties and applications. Presently, I am engaged in the study of groundwater pollution due to uranium and heavy metals contamination in Punjab state. Keywords: Earthquake, geochronology, groundwater pollution, interdisciplinary, nanotechnology, radiation damage, radon

Characteristics of Natural Background Radiation in the Polkowice-Sieroszowice Mine, Poland

Natural radioactivity in underground locations is the main parameter for the safety of work (occupational hazards) and for the success of experiments in physics or biology requiring unique conditions. The characterization of natural prominence was carried out in the Conceptual Lab development in one of KGHM deep copper mines co-ordinated by KGHM Cuprum R&D. Natural radioactivity studies were performed and included in situ gamma spectrometry, neutron flux measurements, radon concentration, and alpha and gamma laboratory spectrometry measurements of rock samples. At a depth of 1014.4 m (2941.8 m w.e.) within the anhydrite layer, a neutron flux of 2.0 ± 0.2 × 10−6 cm−2 s−1, a gamma-ray dose of 0.008 ± 0.001 μSv/h, a photon flux density of 0.64 ± 0.20 cm−2 s−1, and a radon concentration of 6.6 Bq/m3 were determined. Laboratory analyses of 226,228Ra, 40K, and 238,234U concentrations in collected rock samples showed low values. The exceptionally low level of natural radioactivity in the Polkowice-Sieroszowice mine makes this location a unique place for scientific research.

Assessment of radon exhalation rates in mineral rocks used in building decoration in Nigeria

The recent interest in the applications of mineral rocks for interior building decoration has been a major concern from the radiological perspective because the breaking down of rocks into various shapes and sizes releases radioactive gaseous element that is harmful to human health. Hence, this study assessed the radon exhalation rates of different rock types in Nigeria and their implications on human health. A total of 45 samples comprising five samples per rock type were prepared, packed, and sealed inside a modified closed can and thereafter subjected to radon concentration measurement using a RAD7 detector. The results of the study showed that granite and limestone rock types had high radon concentrations and exhalation rates as compared to other rock samples assessed. The radon concentration for granite and limestone rockfalls within the action level limit. Thus, effort should be made to ensure adequate ventilation of any building that uses these rock types in building decoration. The results obtained can be used as baseline data for future investigation of the rock types in any locality.

Radon Survey in Bank Buildings of Campania Region According to the Italian Transposition of Euratom 59/2013.

222Rn gas represents the major contributor to human health risk from environmental radiological exposure. In confined spaces radon can accumulate to relatively high levels so that mitigation actions are necessary. The Italian legislation on radiation protection has set a reference value for the activity concentration of radon at 300 Bq/m3. In this study, measurements of the annual radon concentration of 62 bank buildings spread throughout the Campania region (Southern Italy) were carried out. Using devices based on CR-39 solid-state nuclear track detectors, the 222Rn level was assessed in 136 confined spaces (127 at underground floors and 9 at ground floors) frequented by workers and/or the public. The survey parameters considered in the analysis of the results were: floor types, wall cladding materials, number of openings, door/window opening duration for air exchange. Radon levels were found to be between 17 and 680 Bq/m3, with an average value of 130 Bq/m3 and a standard deviation of 120 Bq/m3. About 7% of the results gave a radon activity concentration above 300 Bq/m3. The analysis showed that the floor level and air exchange have the most significant influence. This study highlighted the importance of the assessment of indoor radon levels for work environments in particular, to protect the workers and public from radon-induced health effects.

Towards a better assessment model of transient radon concentrations in dwellings basements for the study of the effectiveness of soil radon mitigation systems designs

In order to study effectiveness of soil radon mitigation systems in dwellings basements, it is necessary to develop robust numerical models that can estimate time-varying radon concentration in the basements. However, development of such models is a very challenging topic. Indeed, there are three difficult tasks that have to be solved: i°) to characterize soil and foundation materials hydraulic properties, and geometry, length, and position of cracks inside these materials, ii°) to solve discontinuity due to free gas flow in a basement volume embedded within a tortuous porous material, and iii°) to characterize the dwelling occupation mode by the inhabitants. The purpose of this work is twofold: first, to investigate the performance of a meshed-basement model (BM1), compared to classical mass balance models (BM2), in simulating measured fluctuations in time of point-radon concentration in the basement; and second, to study efficiency of soil depressurization systems (SDS) designs in reducing the higher radon concentrations in basements due to higher under-pressurizations.Application of both models to an experimental dwelling showed that BM1 is more efficient than BM2 in that it can better simulate both measured radon concentration and radon-entry-rate. Numerical SDS-scenarios by using BM1 showed that the basement sub-slab depressurization (SSD) alone is a costly solution for radon mitigation. However, scenarios combining SSD with a sump pumping well (SPW) design in the soil adjacent to the wall, showed to be a good alternative because it involves less energy for soil air extraction.

Measurement of radon concentrations and their annual effective doses in soils and rocks of Jaintiapur and its adjacent areas, Sylhet, North-east Bangladesh

Measurement of radon concentrations and their annual effective doses in soils and rocks of Jaintiapur and its adjacent areas, Sylhet, North-east Bangladesh

Occupational Radon Assessment in Underground Storage Facilities in Saudi Arabia.

An occupational radon assessment was conducted at five underground storage facilities in the Kingdom of Saudi Arabia to evaluate the radon concentration and determine if remedial action is required to ameliorate conditions and ensure compliance with international guidance on acceptable radon levels in working environments. The assessment was carried out in four operational areas in the underground storage facilities routinely occupied or visited by workers. Initial radon concentrations were obtained using 293 passive CR-39 Nuclear Track Detector (NTD) radon dosimeters installed in the four operational areas for all the underground storage facilities. The detectors were left in place for 12 mo. As some of the radon measurements exceeded the International Atomic Energy Agency reference level of 1,000 Bq m-3 for radon in workplaces, a follow-up assessment was conducted using a real-time monitoring device in locations where high radon levels were observed. The measured radon concentrations in the four operational areas in three of the five underground storage facilities were below the reference level, and in the remaining two storage facilities, low ventilation rates in one operational area were identified as the principal cause of elevated radon concentrations. Notwithstanding, the potential radiation dose from radon exposure was determined to be well below the International Commission on Radiation Protection reference annual dose level of 10 mSv in all five underground storage facilities. Radon exposure to workers in all the underground storage facilities was found to be within the reference dose level for workplaces and does not pose an acute health risk.

Measurement of outdoor Radon Concentrations in Soil Samples collected from Karabuk University in Turkey by using CR-39 Detector

In this work, radon gas concentration in (35) samples of soil collected from Karabuk University in Turkey was measured by using nuclear track detector (CR-39). The content of radium, the rate of surface exhalation and the rate of mass exhalation have been assessed. The concentrations of radon were varied from (16.348 Bq.m−3) to (196.988 Bq.m−3). Results indicate that the equivalent content of radium varied from (0.386245 Bq.kg−1) to (4.654255 Bq.kg−1). The exhalation rate for surface varied from (0.002007 Bq.m−1.h−1) to (0.023031 Bq.m−1.h−1). The exhalation rate for mass varied from (0.000319 Bq.kg−1.h−1) to (0.00366 Bq.kg−1.h−1). All the obtained results found to be less than the corresponding limits for the world. Thus, based on the radon gas concentration and radiation, the equivalent content of radium (CRa), exhalation rate for the area (EArea) and exhalation rate for the mass (EMass) in this area have no risk to the human’s health.

A Quantitative Assessment of Indoor Radon Level and Its Annual Effective Dose in Buildings of Gachin Rural District in Hormozgan Province, Iran

Introduction: Measurement of indoor radon concentration and its determining factors is crucial for improving public health and developing proper methods that can reduce indoor radon concentrations. This study aimed to measure the indoor radon concentration and to examine its variations in relation to variables, such as the construction materials, ventilation, and age of buildings. Material and Methods: Indoor radon concentrations were measured using solid-state nuclear track detectors (SSNTDs) during winter. Each detector was mounted 50-90 cm above the surface flooring of bedrooms and living rooms. After three months of exposure, the detectors were collected and transferred to a laboratory. They were then etched in 6.25 N NaOH solution in a bath at a constant temperature of 90°C for 240 minutes. Next, the detectors were washed with distilled water and dried. The alpha particle tracks were counted using an automatic alpha track counting system. Results: The mean radon concentration was 53.20 Bq/m3,and 94% of the samples had a radon concentration 3, which is the action level proposed by the World Health Organization (WHO). The annual effective dose varied from 0.25 mSvy-1 to 3.05 mSvy-1, with a mean dose of 0.91 mSvy-1. The results showed that the type of constructed materials and ventilation influence the indoor radon concentration in winter. Conclusion: The annual effective dose in the study area was below the global average of 1.15 mSvy-1. Therefore, local residents must be informed about the health risks of high radon concentrations and understand the role of improved ventilation in reducing the indoor radon levels.

Evaluation of radon, radium and gamma radiation at the environmental preservation area of Passaúna river, Brazil

The objective of this research was to evaluate the levels of natural radiation in the Environmental Protection Area (APA) of the Passaúna River (Campo Largo region) in the state of Paraná, Brazil. Gamma radiation measurements were obtained with the gamma spectrometer, and for the measurements of radium and radon concentrations in soil and water the AlphaGUARD monitor and its accessories were used. Until the present time, 4 water samples from Passaúna’s River, 2 well water samples from the region, 2 sample of a secondary lake and 4 soil samples. The results show that the gamma spectrometric measurements found values ranging from 0.052 to 0.204 μSv / h. However, the results of the radon concentrations in the soil were significant, since the values obtained varied from 110 ± 1.30 kBq/m³ to 9 ± 0.80 kBq/m³, which results can be compared with the radon and radio measurements obtained in the wells water, which indicated values higher than the national limit of 0.5 Bq/L, established by the Brazilian Ministry of Health, and the World Health Organization. The values in the lake water were lower the limits. More measurements are needed to map the region to understand the radiation levels and to correlate water and soil measurements with the geological features of the place.

Measurement of 222Rn Exhalation Rate from Natural Rubber Latex Pillows Randomed from Online Market in Thailand

Radon is a natural radioactive gas, and it is increasingly interesting worldwide because it affects the human healthy and increases lung cancer risk when people receive high concentrations over extended periods of time by inhalation. The study was to measure the radon concentration, determine the radon exhalation rate, and estimate annual effective dose level in order to set up a policy on controlling the contamination of radon in the natural rubber latex products in Thailand, and the radon concentrations were measured from natural rubber latex pillows randomized from online market in Thailand by closed chamber system technique with ATMOS 12 DPX. The results showed that the equilibrium radon concentrations were ranged between 11 ± 2 and 43 ± 5 Bqm–3 with an average value of 17 ± 9 Bqm–3. All measured radon concentrations were well below the allowed maximum contamination level of radon concentration in collected samples of 148 and 300 Bqm–3, recommended by the USEPA and the ICRP, respectively. The exhalation rates from natural rubber latex pillows were ranged 12 ± 3 and 60 ± 7 mBq m–2 h–1 with an average value of 25.7 ± 14.4 mBq m–2 h–1. The annual effective doses calculated for inhalation were between 0.12 ± 0.03 and 0.43 ± 0.05 mSv y–1, and also well lower than the annual effective dose for general public (1.0 mSv y–1) recommended by the ICRP.

The new Austrian indoor radon survey (ÖNRAP 2, 2013–2019): Design, implementation, results

The delineation of radon prone areas is one of the central requirements of the European Council Directive 2013/59/EURATOM. It is quite a complex task which usually requires the collection of radon data through an appropriate survey as a first step. This paper presents the design and methodology of the recent Austrian radon survey (ÖNRAP 2, 2013–2019) and its implementation. It details the results of the nationwide survey as well as correlations and dependencies with geology and building characteristics. The paper also discusses the representativeness of the survey as well as advantages and disadvantages of the selected approach.For the purpose of establishing a new delineation of radon prone areas in Austria we distributed approximately 75,000 passive long-term radon detectors. They were offered to selected members of the voluntary fire brigades and this resulted in about 50,000 radon measurements. Thus, a return rate of about 67% was achieved. The distribution of the radon results closely follows a log-normal distribution with a median of 99 Bq/m³, a geometric mean of 109 Bq/m³, and a geometric standard deviation factor of 2.29. 11% of the households show a mean radon concentration above the national reference level of 300 Bq/m³.Important data on building characteristics and the location of the measured rooms were collected by means of a specific questionnaire and a measurement protocol that were handed out together with the radon detectors. We were able to identify significant correlations between the indoor radon concentration and geology, the year of construction, and the coupling of the room to the ground (basement yes/no, floor level).Being a geographically-based and not a population-weighted survey, the comparison of building characteristics with the Austrian census data confirms that rural areas are over-represented in this survey.As a summary, the selected approach of conducting passive long-term radon measurements in selected dwellings of members of the voluntary fire brigades proved to be an efficient method to collect reliable data as a basis for the delineation of radon prone areas. The next step was to eliminate factors that influence the measured radon concentration through appropriate modelling. Based on the results predicted by the model radon areas are then be classified. This will be presented in a subsequent publication.

Monitoring Radon Levels in Hospital Environments. Findings of a Preliminary Study in the University Hospital of Sassari, Italy

Background: The aim of this preliminary study was to measure radon concentrations in a hospital in order to verify to what extent these concentrations depend on various environmental variables taken into consideration, and consequently to determine the urgency to implement mitigation actions. Methods: The rooms where the concentration of the gas was potentially highest were monitored. Investigators adopted a Continuous Radon Monitor testing device. Qualitative and normally distributed quantitative variables were summarised with absolute (relative) frequencies and means (standard deviations, SD), respectively. As regards environmental variables, the difference in radon concentrations was determined using the rank-based nonparametric Kruskal–Wallis H test and the Mann–Whitney U test. Results: All measurements, excluding the radiotherapy bunkers that showed high values due to irradiation of radiotherapy instruments, showed low radon levels, although there is currently no known safe level of radon exposure. In addition, high variability in radon concentration was found linked to various environmental and behavioural characteristics. Conclusions: The results on the variability of radon levels in hospital buildings highlighted the key role of monitoring activities on indoor air quality and, consequently, on the occupants’ health.