Radon Concentration Levels Research Articles

Short-term characterization of the indoor air radon concentration in a XII century monastery converted into a school building

An ancient monastery placed in Ponte de Lima, an inner village in Alto Minho region, North of Portugal, was monitored in order to assess radon gas concentrations. The aim of this paper is to perform a short-term radon gas characterization to assess the radon risk in a school building and therefore propose adequate mitigation strategies. The experimental campaign took place during spring and summer of 2017 and was carried out in 2 complementary steps involving 17 different sites. This study revealed that the radon concentration levels are above the legal limit of 400 Bq.m-3, in 77% of the samples. The value rises to 86% when Euratom Directive limit of 300 Bq.m-3 is considered. Furthermore, the results obtained that indoor radon concentration varies with the occupancy of the rooms, since it is evident that the human ventilation actions have a considerable impact on the reduction of its concentration.

Soil radon gas in some soil types in the rainy season in Ho Chi Minh City, Vietnam

Field experiments on soil radon and radium concentrations were carried out in eighteen locations in Ho Chi Minh City, Vietnam. Soil radon depth profiles (10–100 cm) of loam, sand and clay soil samples in the rainy season were measured using RAD7 radon detector. Mean concentrations of 222Rn and 226Ra were found to be 28.6 ± 2.0 Bq.kg−1 and (1.56 ± 0.06) × 104 Bq.m−3 in clay soil while they are 31.2 ± 2.5 Bq.kg−1 and (1.15 ± 0.05) × 104 Bq.m−3 in loam soil. They are 30.7 ± 2.0 Bq.kg−1 and (9.37 ± 0.52) × 103 Bq.m−3 in sandy soil, respectively. Values of radon diffusion length and diffusion coefficient for different soils were obtained using semi-empirical fit method linked to the poor diffusion of gas in clay soil (0.2 × 10−6 m2 s−1), the moderate diffusion coefficient (0.9 × 10−6 m2 s−1) in loam and good diffusion of radon gas in sandy soil (1.4 × 10−6 m2 s−1). An unexpectedly unclear linear relation was found between soil radon concentration and radium content. The grain size smaller than 0.1 mm was dominant reason for the lowest (0.15 ± 0.01) and highest (0.40 ± 0.03) values emanation coefficient for sand and clay soil, respectively. A strong positive correlation was found between radon concentration and soil pH level leads to soil pH is an indirect dynamic parameter affecting the migration of radon in soil.

Indoor and Outdoor Radon Concentration Levels in Lebanon.

Lebanon's lung cancer rates, among the highest in the Arab region, contribute to the burden of noncommunicable diseases. A number of studies have shown that lung cancer risk increases when smokers vs. nonsmokers exposed to elevated radon levels are compared. This research employs indoor and outdoor space and time concentration surveys across Lebanon, where the smoking rate among the population is among the highest in the world. The distributional properties of measured radon concentration were shown to be lognormal with median indoor and outdoor concentrations of 17 and 10 Bq m, respectively. Standard deviation for indoor concentrations was 1.2 times smaller than its outdoor counterpart, suggesting that weather-related patterns affect outdoor radon concentration variability. No significant spatial association was detected across seasons for indoor and outdoor radon concentrations. Geographical location, proximity to faults, and housing construction material had no significant impact on outdoor and indoor radon concentration variations. When lognormal distributions were used to determine exceedance probability of the recommended reference radon concentration, they were smaller than 0.1%. While exhibiting high seasonal variability, the study shows that radon does not appear to be a public health concern in Lebanon.

Estimation of indoor radon levels using etched track detector

In this investigation, the activity levels of Indoor Radon-222, effective radium contents, exhalation rate of radon, and annual effective dose are reported for different indoor locations (Offices, Laboratories, Meeting rooms, and Storerooms) at two students divisions (boys, and girls) in science college, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh, Saudi Arabia. Sealed-can technique based on CR-39 nuclear tracks detector was distributed to radon gas survey. The obtained results indicate normal levels of indoor radon concentration and effective radium content in all locations of the studied area. A strong correlation (R2 = 1) has been observed between effective radium content and radon exhalation rate. There is a slight increase in the values of exhalation rate at all locations. The average values of annual effective dose for boys division are 1.26, 1.51, 2.02, and 2.38 mSvy−1 for meeting rooms, offices, storerooms, and laboratories, respectively. For girls division, the average values of annual effective dose are 0.86, 0.95, 1.53, 0.78 mSvy−1 for meeting rooms, offices, storerooms, and laboratories, respectively.

INFLUENCE OF BUILDING FEATURES ON RADON ACCUMULATION IN KINDERGARTENS OF THE SVERDLOVSK REGION

Objective: To study the levels of radon accumulation in kindergartens in Sverdlovsk Region and to deter­mine the relationship between radon concentration, and building characteristics. To perform a detailed anal­ysis of radon entry and accumulation in the kindergarten, in which radon concentration exceeds the safety standards. Materials and methods : Track detectors REI-4 on the base of LR-115 film were used. Detectors were installed in playrooms and bedrooms for day nap. In each kindergarten, at least 3 rooms were examined. The measurements were carried out twice a year, during the warm and cold seasons. The duration of exposure of the detectors was 2–3 months in each season. The AlphaGUARD radon monitor was installed in the kinder­garten with a high level of radon concentration. Results: It is shown that the distribution of radon concentration in the kindergartens of the Sverdlovsk region can be described by a lognormal distribution with an average value of 60 Bq/m 3 , a geometric mean of 44 Bq/m 3 and a standard geometric deviation of 2.23. A statistically significant differ­ence was found between the mean values of radon concentration in subgroups of buildings constructed at different periods. For the kindergartens constructed in 1950–1969, the average radon concentration was 85 Bq/m 3 , for buildings built in 1970–1989 – 54 Bq/m 3 . When comparing subgroups of rooms with different types of windows (all buildings, ground floors) it was found that in rooms with PVC windows, radon concentration is almost twice as high then in rooms with wooden windows. For the kindergarten, in which the annual radon concentration in the playroom was 620 Bq/m 3 , it was shown, that if the proper ventilation regime of this room is observed, the average radon concentration during the presence of children does not exceed 120 Bq/m 3 . Conclusions . Factors affecting the indoor radon accumulation in the kindergartens are the type of building materials associated with different periods of building construction and the type of windows. When radon concentration measured in kindergartens reach sanitary standards, it is advisable to conduct an additional study of the daily radon variations, since during the active operation of the premises (working hours) radon levels may be significantly lower

Radon Concentration And Dose Assessment In Well Water Samples From Karbala Governorate Of Iraq

There are numerous studies around the world about radon concentrations and their risks to the health of human beings. One of the most important social characteristics is the use of water wells for irrigation, which is a major source of water pollution with radon gas. In the present study, six well water samples have been collected from different locations in Karbala governorate to investigate radon concentration level using CR-39 technique. The maximum value 4.112±2.0Bq/L was in Al-Hurr (Al-Qarih Al-Easariah) region, and the lowest concentration of radon was in Hay Ramadan region which is 2.156±1.4Bq/L, with an average value 2.84±1.65Bq/L. The highest result of annual effective dose (AED) was in Al-Hurr (Al-Qarih Al-Easariah) region which is equal to 15.00±3.9μSv/y, while the minimum was recorded in Hay Ramadan 7.86±2.8μSv/y, with an average value 10.35±3.1μSv/y. The current results have shown that the radon concentrations in well water samples are lower than the recommended limit 11.1Bq/L and the annual effective dose in these samples are lower than the permissible international limit 1mSv/y.

Radon in Brazilian underground mines

Radon is a chemically inert noble radioactive gas found in several radioactive decay chains. In underground mines, especially those that contain or have contained ores associated with uranium-bearing minerals, workers might be exposed to high levels of radon and its decay products (RDP). This work aims to investigate whether the exposure of workers to radon gas and its progeny has been evaluated in Brazilian non-uranium and non-thorium underground mines. Any such results and control measures undertaken or recommended to maintain concentrations under Brazilian occupational exposure limits (OELs) are documented. The methodology we adopted consists of three main phases. The first was an extensive bibliographical survey of the concentration levels of radon and RDP, as well as the radiation dose estimates, considering measurements made heretofore by various Brazilian researchers and exhibiting original measurement work undertaken by the one of the authors (mine O). In the second phase, the values obtained were compared with OELs. In the third phase, any control measures undertaken in mines with high exposure of workers to radon and its progeny were verified, and the adopted controls were determined. Radon concentration data obtained from 52 campaigns in 40 underground mines were analyzed. The results show that assessment of the exposure of workers to radon and its progeny was undertaken in many mines at least once, and that radon levels in 62.5% of the mines, when visited for the first time, were below the Brazilian OELs. As expected, the main control measure adopted or recommended was improvement of the ventilation system.

Estimate Level of Radon Concentration for Drinking Water in Some Regions of Baghdad City

In this study, the assessment of radon concentration in drinking water in some regions of Baghdad city in Iraq has been studied using CR-39 solid-state nuclear track detector technique. A total of 18 samples selected from 6 region (5 samples from each region) in Baghdad city have been placed in the dosimeters for 50 day. The average radon concentration was found to be 516.1 hbox { Bq/m}^{3} which is greater than the standard international limit (300 hbox { Bq/m}^{3}). The potential alpha energy concentration and annual effective dose have been calculated. A proportional relationship between the annual effective dose and radon concentration within the studied region has been certified.

Radon Concentration in the Work Atmosphere of Cement Plants in the Sulaymaniyah Area, Iraq

This work reports the radon concentration level in the work environment of cement plants (CPs) located in the Sulaymaniyah city-North of Iraq. This survey for the radon concentration is performed in 24 sectors of three different CPs including Tasluja, Mass, and Bazian. The measurements were recorded using solid state nuclear track detector (CR-39 NTDs). The radon effective dose μSv/hr correlated weakly with the gamma effective dose μSv/hr to enhance the radon concentration measuring. The detector was fixed in different places of the plants such Crusher, Correction stores, Raw Mill (Grinding Mill), Preheater (Tower), Clinker, and Cement Storage. The arithmetic mean (AM) value of radon concentration (Ca) was found to be 98 ± 9, 101 ± 10, and 125 ± 10 Bq m −3 and the arithmetic mean value of annual effective dose (E) of radon was 0.767, 0.753, and 0.962 mSv y −1 for Tasluja, Mass, and Bazian CPs, respectively. The maximum values of about 222 ± 20 Bq m −3 and 1.402 mSv y −1 , respectively, in sector III (Grinding) at Bazian CP. The achieved results reveal that the maximum value of radon concentration in all sectors of the CPs is below the international standard value (300 Bq m−3) of both the World Health Organization and International Commission on Radiological Protection.

Indoor radon concentration in Korearesidential environments.

The purpose of this study is to provide basic data for the evaluation and management of health effects with respect to exposure to radon within residential environments in South Korea. It is part of a case-control study to develop a management plan based on indoor radon exposure levels and assess their impact on health. To investigate the long-term cumulative concentration levels of radon, 599 patients who have respiratory diseases were recruited in South Korea, and alpha track detectors were installed in their residences for a period of 3months from mid-2015 to late 2016. A survey was then conducted to determine the factors affecting the radon concentration. The radon concentration levels were analyzed in conjunction with the survey results. The results show that the arithmetic mean of the radon concentrations in domestic residences was in the range of 70.8 ± 65.2Bq/m3. An analysis of covariance (ANCOVA) was performed to identify the environmental factors affecting the radon concentration and contributing to variations in the residential radon concentration based on the height of the residence. The results show that the contribution of the local environmental factor to the variation in radon concentration (p < 0.05) was greater than that of other environmental factors. Although no statistically significant difference was found with regard to the construction year of the building before the control (p > 0.05), the same was found with regard to the construction year after the control (p < 0.05).

Estimation and seasonal variation of indoor radon and gamma dose level in the dwellings of entire east coast of Tamil Nadu, India

Radon concentration and gamma dose rates have been measured in different types of dwellings (94 dwellings) of the east coast of Tamil Nadu, India, on a quarterly basis using solid state nuclear track detectors and thermoluminescent dosimeters, respectively. Higher level of radon concentration is observed for winter season followed by spring, rainy, and summer seasons. On the contrary, the gamma dose rate for winter season is slightly lower than other three seasons. In this study, the average annual radon concentration (19.02 Bq/m3) is much lower than the recommended safe limit of 300 Bq/m3 while gamma dose rate (1.5 mGy/y) is much higher than the world average value of 0.520 mGy/y.

Measurement of radon concentration in drinking water and estimation of radiation dose to the publics of Hassan city, Karnataka, India

In the present paper, the radon concentration in drinking water samples of the Hassan city, Karnataka state, India, was analyzed using the radon emanometry technique. The measured radon concentrations ranged from 19.5 ± 1.5 to 121.8 ± 5.6 Bq/L with an average value of 61.4 ± 3.3 Bq/L. This study reveals that all the drinking water samples have radon concentration levels higher than the maximum contaminant level of 11 Bq/L as suggested by the Environmental Protection Agency, and 75% of the recorded radon concentration values were found to be well below the action level of 100 Bq/L recommended by the World Health Organization. The average annual effective dose to the population of the studied area was found to be slightly greater than the safe limit of 100 μSv/y recommended by the World Health Organization.

Estimation of underground water radon danger in Bakreswar and Tantloi Geothermal Region, India

The main aim of the study is to present an evaluation of radon concentration in underground water of Bakreswar and Tantloi geothermal region which is mainly used for drinking purposes of the local people. Water samples were collected from tube-wells at 173 different locations. The radon (222Rn) concentration level was observed to fluctuate widely between 3.3 and 803.8 Bq/l with an average of 106.8 Bq/l. Nearly 42% of the samples had radon concentration above the safe limit of 100 Bq/l recommended by World Health Organisation (WHO) and European Union Commission (EU). Considering the WHO and International Commission on Radiological Protection recommended water consumption rate for adults (730 l/year) the corresponding total annual effective dose of the samples were estimated to assess the probable health risk. Total annual effective dose of the samples were varied between 16.72 and 4079.47 µSv/year with an average value of 541.92 µSv/year. About 95% samples exceed the WHO and EU Commission proposed safe limit of 100 µSv/year.

Indoor Radon Concentration Related to Different Radon Areas and Indoor Radon Prediction

Indoor radon has been observed in the buildings at areas with different radon risk potential. Preventive measures are based on control of main potential radon sources (soil gas, building material and supplied water) to avoid building of new houses above recommended indoor radon level 200 Bq/m3. Radon risk (index) estimation of individual building site bedrock in case of new house siting and building protection according technical building code are obligatory. Remedial actions in buildings built at high radon risk areas were carried out principally by unforced ventilation and anti-radon insulation. Significant differences were found in the level of radon concentration between rooms where radon reduction techniques were designed and those where it was not designed. The mathematical model based on radon exhalation from soil has been developed to describe the physical processes determining indoor radon concentration. The model is focused on combined radon diffusion through the slab and advection through the gap from sub-slab soil. In this model, radon emanated from building materials is considered not having a significant contribution to indoor radon concentration. Dimensional analysis and Gauss-Newton nonlinear least squares parametric regression were used to simplify the problem, identify essential input variables and find parameter values. The presented verification case study is introduced for real buildings with respect to various underground construction types. Presented paper gives picture of possible mathematical approach to indoor radon concentration prediction.

Hydrological Changes Induced by Distant Earthquakes at the Lujiang Well in Anhui, China

The Lujiang well, a 63 °C artesian well, recorded sustained hydrological changes following the 1999 Chi–Chi M w 7.6, the 2008 Wenchuan M w 7.9, and the 2011 Tohoku M w 9.0 earthquakes, including rises in the water radon concentration, water pressure, discharge and water level, and drops in the water temperature. These hydrological changes are synchronous and have similar amplitudes. The permeability inferred through the tidal response of water level showed insignificant change after the three earthquakes. We attribute the observed hydrological changes to the increase in the vertical recharge on the basis that the water radon concentration of the Lujiang well increased following the increase of recharge to the well; significant vertical flow exists in the well-aquifer system; the well has a lower water radon concentration and a higher water temperature than its adjacent wells with different aquifers.

Simultaneous Measurements of Nanoaerosols and Radioactive Aerosols Containing the Short-lived Radon Isotopes.

The activity size distribution of the Equilibrium-Equivalent Concentration (EER) of 222Rn is one of the most important parameters for the estimation of radiation dose by inhalation of radon decay products. A series of measurements of the EER activity size distribution were performed by the screen diffusion battery in Radon-Aerosol chamber (10 m3) at the National Institute for Nuclear, Chemical, and Biological Protection (SUJCHBO). These measurements were performed at different levels of radon concentration. For this study, the Graded Screen Array Diffusion Battery (GSA DB), developed by the SUJCHBO (based on Earl Knutson and Robert F Holub design), consists of 10 screens and backup filter used to collect all particles that penetrated the screens. The measuring range of this GSA DB allows measuring the radioactive nanoaerosols in the size range from 0.5 to 100 nm. The Earl Knutson algorithm was used for EER activity size distribution evaluation. The results of EER activity size distribution were subsequently compared with the aerosol particle size distribution measured by Scanning Mobility Particle Sizer Spectrometer (SMPS 3936 N, TSI Inc., MN, USA).

A preliminary study for conducting a rational assessment of radon exposure levels.

The aim of this study was to determine the factors that go into a highly reliable estimate of radon exposure levels for use in setting up the case-control study. To this end, the present study conducted a multi-faceted investigation of the distribution of radon concentrations in the bedrooms and living rooms of 400 households in the target areas during the winter months from December 2014 to February 2015. We determined that taking the mean value of the radon concentration levels detected in the bedroom and living room as the representative value of residential concentration is appropriate, given the usability of previous research data and the difference in the concentration levels between the two. In terms of detector placement, we found that detectors should not inconvenience residents or be affected by an air current. Further, we found that housing type should distinguish between regular housing (single-detached, row, and multiplex housing) and apartments but that the building type was not a key factor in the assessment of radon exposure levels. Houses should be classified into those constructed with soil (red clay) and those with constructed with general building materials for the assessment of radon exposure levels.

Radon measurements and dose estimate of workers in a manganese ore mine

In the new European Basic Safety Standard (EU-BSS), a new reference level for indoor radon concentration in workplaces has recommended that the annual average activity concentration of indoor radon shall not be higher than 300Bqm−3. This paper describes the radon concentration level in an underground workplace (manganese ore mine) over long time intervals (4 years). Several common radon monitors devices – including NRPB and Raduet (as a passive method based on CR-39), AlphaGUARD PQ 2000Pro, SARAD EQF3220, TESLA and Pylon WLX (as active methods) – were used for continuous radon measurements. The output results were used, first, to comprised the result of each device, based on conditions present in underground mines; Second, to have comprehensive measurements about all factors that cause workers exposure to radiation (each monitoring device specified for a unique measurement). The results indicate that the mine's staff had successful efforts to reach the strict requirement of the new EU-BSS, and the average annual radon activity concentrations during the working hours were below 300Bqm−3 in the investigated period. The paper presents the effective dose calculations; applying different equilibrium factors suggested by the literature and calculated basing on our measurements at the site, concluding that the differences could be about threefold.

Exposure to underground radon in and around Kolkata Municipal Corporation area: an exhaustive study

Air radon survey was carried out at different underground locations at Kolkata using radon monitor. Average radon concentration for basements was found to be 22.70 ± 1.12 Bq/m3 with maximum 59.00 ± 7.18 Bq/m3 and minimum 8.50 ± 3.14 Bq/m3. Average level for sub-ways was 23.05 ± 2.59 Bq/m3 fluctuating between maximum 39.00 ± 1.24 Bq/m3 and minimum 13.50 ± 1.78 Bq/m3. In comparison, open air background at basement entrance was 19.44 ± 1.06 Bq/m3 and subway entrance was 18.58 ± 1.14 Bq/m3. Annual effective dose was calculated to assess probable health risk. Radon concentration level and annual effective dose were found well below safe levels recommended by International Agencies WHO and UNSCEAR.

Outdoor radon concentration in China

Abstract A nationwide survey was conducted in 2014 to investigate environmental outdoor radon level in 33 provincial cities across China. The radon detector used was a passive-type solid-state nuclear track detector, CR-39. Measurements were conducted under the same condition following the quality control programme. Outdoor radon concentrations in China ranged from 3 to 30.0 Bq·m−3. The annual arithmetic and geometric mean radon concentration were 14 and 13.2 Bq·m−3, respectively. The radon concentrations in the locations near or along coastline were lower than the average value, while those located in the inland area were higher. As a whole, the result showed no big difference from the data measured during the period 1983–1998. It demonstrated that the outdoor radon concentration level in China has not been changing remarkably for 20 years.