Progeny In Dwellings Research Articles

Estimation of indoor radon and thoron levels along with their progeny in dwellings of Roopnagar District of Punjab, India

Estimation of indoor radon and thoron levels along with their progeny in dwellings of Roopnagar District of Punjab, India

Measurement the Concentrations of Radon and Thoron and Their Progeny in the Air Samples of Al-Haswaa City in Babylon province

In this work, measurements of radon, thoron, and their progeny in dwellings and measurements of radon in air of Al-Haswaa city were displayed using SSNTD detection technique, which has a very low detection limit. The radon concentration were varied from 34.736 to 55.789 Bq.m−3 with average value 47.60 Bq.m−3 while the thoron concentration varied from 20.526 to 61.513 Bq.m−3 with average value 33.552 Bq.m−3. The annual effective dose from the corresponding measured concentration of radon and thoron in the various dwellings were varied from 1.704 to 2.949 mS.y−1 with average value 2.061 mSv.y−1, which is within the recommended ICRP intervention level of 3 -10 mSv.y−1.

Thoron exposure in Dutch dwellings – An overview

In the Netherlands considerable attention has been given to the exposure from thoron progeny in dwellings. For this purpose a nationwide survey on the thoron exhalation and thoron progeny concentration has been completed in 2015. Furthermore, extensive laboratory studies have been performed to measure activity concentrations and thoron exhalation rates from regular Dutch building materials. The purpose of this study is to demonstrate if the findings from both field experiments and laboratory results are consistent. For this reason measured properties of building materials and surface barriers, in-situ measurements on air ventilation and thoron(progeny) in dwellings as well as advanced computational modelling on indoor air and aerosol behaviour have been used. The results demonstrate that median and mean thoron progeny concentrations of 0.53 and 0.64 Bq·m−3 found in the survey are comparable with the mean concentration of 0.57 Bq·m−3 obtained from laboratory testing and calculation. Furthermore, upper thoron progeny concentrations from the survey and the calculations are with respectively 13 and 14 Bq·m−3 also in good agreement. Such elevated concentrations lead to an effective doses of around 4 mSv per year. The study also includes worst-case scenarios on the application of surface materials high on 232Th, and the expected reduction in thoron progeny when using mainstream mitigation measures.

Estimation of Indoor Radon and Its Progeny in Dwellings of Akoko Region, Ondo State, Southwestern Nigeria

Estimation of Indoor Radon and Its Progeny in Dwellings of Akoko Region, Ondo State, Southwestern Nigeria

Monitoring of radon, thoron, their progeny concentrations in dwellings, and radon exhalation rates of soil/sand of Rupnagar district, Punjab, India

Radon and its progeny are major contributors in the radiation dose received by general population of the world. Keeping this in mind, the environmental monitoring of radon–thoron and their progeny in dwellings of district Rupnagar, Punjab, India has been carried out. Both radon–thoron twin dosimeter cups and the newly developed pin-hole dosimeters cups by BARC, India were used for the study. The study reveals good agreement between the values measured by the two types of dosimeters. Radon exhalation rate from soil samples of these dwellings/areas have been carried out using “Canister Technique.” The radon exhalation rates of some soil samples of these dwellings/areas were also measured by an active technique using a continuous radon monitor. Both the active and passive techniques show the exhalation rate values to be lower than the worldwide average. The study of the exhalation rate of the soil samples of Nangal and Anandpur Sahib of the district Rupnagar and the sand samples available from the study area has also been carried out for the possible use as construction material. The in situ gamma dose varied from 0.13 to 0.33 µSv/h.

Study of Indoor Radon, Thoron, Their Progeny Concentration and Radon Exhalation Rate in the Environs of Mohali, Punjab, Northern India

Radon and its progeny are major contributors that deteriorate the indoor air quality and are the major source of radiation dose received by general population of the world. Keeping this in mind the environmental monitoring of radon-thoron and their progeny in dwellings of district Mohali, Punjab, India has been carried out. The radon-thoron twin dosimeter cups were used for the study. The study of the exhalation rate of the soil samples of Kharar, Kurali and Derabassi of the district Mohali and the sand samples available from the study area has also been carried out for the comparison purpose using can echnique. The aim of the study is the possible health risk assessment in the dwellings of this particular region for which data is not available in literature. The indoor radon concentration varied from 22.8 ± 0.7 Bq/m3 to 45.0 ± 2.2 Bq/m3 with an average of 33.7 Bq/m3 while the thoron concentration in the same dwellings varied from 1.7 ± 0.1 Bq/m3 to 27.6 ± 1.2 Bq/m3 with an average of 12.8 Bq/m3. Annual dose received by the inhabitants in the dwellings under study varied from 0.64 to 1.64 mSv with an average of 1.19 mSv. The radon mass and surface exhalation rates of the soil samples varied from 0.32 to 2.6 mBq/kg/h with an average of 1.36 ± 0.2 mBq/kg/h and from 7.3 to 58.2 mBq/m2/h with an average of 28.3 ± 5.1 mBq/m2/h respectively.

Annual Effective Dose Due to Radon, Thoron and their Progeny in Dwellings of Aligarh City and around a Thermal Power Station in Aligarh District, U.P., India

The present study was conducted to measure integrated radon and thoron concentration levels in dwellings of Aligarh city and around the thermal power station situated in Aligarh District. Solid State Nuclear Track Detectors (LR-115, TYPE-II) based twin cup dosimeters were used for this purpose. Radon and thoron progeny concentration levels in terms of Potential Alpha Energy Concentrations (PAECs) and annual effective dose received by the inhabitants in studied dwellings were estimated from observed values of radon and thoron gas concentrations. The evaluated mean values of radon and thoron gas concentration in Aligarh city were 30.3 Bqm-3 (SD =10.6) and 10.2 Bqm-3 (SD =6.1) respectively and around thermal power station 23.6Bqm-3(SD = 5.2) and 7.7 Bqm-3 (SD= 1.9) respectively. The evaluated mean value of radon and thoron progeny concentration were 3.3 mWL (SD=1.1) and 1.1 mWL (SD= 0.7) respectively, in Aligarh city and 2.6 mWL (SD=0.6) and 0.8 mWL (SD= 0.2) around thermal power station. The estimated average value of annual effective dose in studied dwellings was 0.9 mSv (SD= 0.3) in Aligarh city and 0.7 mSv (SD= 0.2) around thermal power station.

220Rn and its progeny in dwellings of Korea

Concentrations of 220Rn and its progeny were measured in 450 dwellings from 2002 to 2004 using two kinds of simple passive 222Rn and 220Rn monitors, Radopot TM and 220Rn progeny monitor. The annual arithmetic mean (AM) and geometric mean (GM) of 220Rn concentrations were 40.4 and 10.7 Bq m - 3 , respectively. The annual arithmetic mean (AM) of EEC Tn concentration was 0.89 ± 0.70 Bq m - 3 , and the annual geometric mean (GM) was 0.60 Bq m - 3 (95% confidence interval: 0.43 – 0.78 Bq m - 3 ). The concentrations of 220Rn in Korean-style houses built with mud block were about two times higher than those in apartments. The average annual effective dose due to inhalation exposure to 220Rn and its progeny in dwellings was 0.25 mSv y - 1 .

Simultaneous determination of radon, thoron and their progeny in dwellings

It has been well recognised all over the world that inhalation of indoor radon ( 222Rn), thoron ( 220Rn) and their daughter products contribute a major fraction of total dose to human beings from all possible sources of natural radioactivity. North-eastern region being in a zone of high seismicity, the indoor radon and thoron map of the region will provide a valuable database for any study related to radon and thoron anomalies. Radon enters living area mainly through floor from subsoil and building materials, and starts accumulating in poorly ventilated dwellings. So, concentration of radon and its progeny are usually higher in indoor air than in outdoor air. In the present work, an attempt has been made to assess the levels of radon, thoron and their progeny in dwellings of a few cities in the north-eastern region of India using a passive time integrated monitoring with the help of twin chamber dosimeters having LR-115 as the detector.

Estimation of Thoron Progeny Concentrations in Dwellings with Their Deposition Rate Measurements.

Based on the track-etching technique, a convenient, low-cost, time-integrating monitor was developed for measuring the deposition rate of attached thoron (220Rn) progeny indoors. Measurements of the deposition rates and concentrations of 220Rn progeny were simultaneously carried out in 13 dwellings throughout a year. Quite different deposition rates and concentrations of 220Rn progeny were found among those dwellings. However, seasonal variations of the deposition rates and concentrations were not significant in each dwelling. An average of (0.53±0.11)×10-2cm·s-1 was estimated for the deposition velocity of attached 220Rn progeny indoors, in fair agreement with most of the values for attached 222Rn progeny in dwellings in the literature. Significant correlation (r=0.981) was found between the deposition rates and concentrations of 220Rn progeny, and the deposition velocity for attached 220Rn progeny was relatively constant among the typical dwellings. It suggests that it is possible to estimate indoor 220Rn progeny concentrations using their deposition rates with the proposed simple measurement technique.

The use of track registration detectors to reconstruct contemporary and historical airborne radon ( 222RN) and radon progeny concentrations for radon-lung cancer epidemiologic study

Epidemiologic studies that investigate the relationship between radon and lung cancer require accurate estimates for the long-term average concentrations of radon progeny in dwellings. Year-to-year and home-to-home variations of radon in domestic environments pose serious difficulties for reconstructing an individual's long-term radon-related exposure. The use of contemporary radon gas concentrations as a surrogate for radon-related dose introduces additional uncertainty in dose assessment. Studies of glass exposed in radon chambers and in a home show that radon progeny deposited on, and implanted in, glass hold promise for reconstructing past radon concentrations in a variety of atmospheres. We developed an inexpensive track registration detector for the Iowa Radon Lung Cancer Study (IRLCS) that simultaneously measures contemporary airborne radon concentrations, surface deposited alpha activity density, and implanted 210Po activity density. The implanted activity is used to reconstruct the cumulative radon and radon progeny exposure from the age of the glass and the ratios of the contemporary deposited activiteis to airborne radon gas activity. We placed over 2500 of these detectors in more than 1000 homes and retrieved 97% of them after a one-year exposure period. A preliminary analysis of the 1280 detectors that have undergone quality assurance review shows that the modules are meeting their accuracy and precision goals (10%). There is good correlation (r 2∼0.5) between the total radon exposure estimated from contemporary radon gas measurements and historical average reconstructed from the implanted 210Po surface activity. The linear regression slope of the airborne radon exposure to implanted activity is the same as the room model slope based on typical room parameters. This correlation improves (r 2∼0.7) when the deposited surface activity measurements are added to the linear regression. Thus, track-registration detectors can contribute to accurate radon-related dose assessment in epidemiologic studies. Additional work is planned to incorporate the deposited activities in a more sophisticated reconstruction model.