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Hu J, Wu Y, Saputra MA, Song Y, Yang G, Tokonami S. Radiation exposure due to 222Rn, 220Rn and their progenies in three metropolises in China and Japan with different air quality levels. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2022; 244-245:106830. [PMID: 35124392 DOI: 10.1016/j.jenvrad.2022.106830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 01/22/2022] [Accepted: 01/27/2022] [Indexed: 06/14/2023]
Abstract
Radiation exposure due to radon contributes most of the ionizing radiation exposure to people among natural radiation sources. This research measured the 222Rn, 220Rn by the RADUET and their progeny concentrations by the improved deposition based 222Rn and 220Rn progeny monitor, and the contribution of outdoor PM2.5 concentrations to indoors by a modified steady-state mass balance model in Beijing, Changchun, China and Aomori, Japan. Based on these results, we preliminarily explored the relevance between the city level outdoor PM2.5 exposure and indoor 222Rn, 220Rn inhalation exposure in these three metropolises with different air quality levels. The average equilibrium equivalent radon concentration (EERC) and equilibirum equivalent thoron concentration (EETC) indoor were 17.2 and 1.1 Bq m-3 in Beijing, 19.4 and 1.3 Bq m-3 in Changchun, and 10.8 and 0.9 Bq m-3 in Aomori, respectively. The indoor EERC and EETC in Beijing showed 1.4 and 2.2 times as high as that measured in 2006. The indoor radiation dose due to inhalation presented in a descending order as Changchun, Beijing and Aomori, which were in accordance with their outdoor 222Rn concentrations. The indoor radiation doses due to 220Rn contributed 30% of the total dose in the three cities, indicating that 220Rn cannot be neglected when evaluating indoor radiation dose. It should be noted that, the indoor PM2.5 concentrations of outdoor origin presented strong correlation (r = 0.772) with indoor EETC and moderate correlation (r = 0.663) with indoor EERC, indicating that the PM2.5 of outdoor origin can break the concentration balance of the indoor PM2.5, then affect the indoor 222Rn and 220Rn behaviors, and further affect the inhalation exposure of radon.
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Affiliation(s)
- Jun Hu
- Department of Radiation Measurement and Physical Dosimetry, Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori, 036-8564, Japan; Department of Radiation Science, Graduate School of Health Sciences, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori, 036-8564, Japan; Center for Environmental Remote Sensing, Chiba University, 1-33 Yayoi-cho, Inage, Chiba, 263-8522, Japan.
| | - Yunyun Wu
- National Institute for Radiological Protection, Chinese Center for Disease Control and Prevention, 2 Xinkang Street, Dewai, Beijing, 100088, China
| | - Miki Arian Saputra
- Center for Nuclear Minerals Technology, National Nuclear Energy Agency of Indonesia, Jl. Ps. Jumat, Lebak Bulus Raya No. 9, Cilandak, Jakarta Selatan, 12440, Indonesia
| | - Yanchao Song
- National Institute for Radiological Protection, Chinese Center for Disease Control and Prevention, 2 Xinkang Street, Dewai, Beijing, 100088, China
| | - Guosheng Yang
- National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage, Chiba, 263-8555, Japan
| | - Shinji Tokonami
- Department of Radiation Measurement and Physical Dosimetry, Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori, 036-8564, Japan.
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Study of Surface Emissions of 220Rn (Thoron) at Two Sites in the Campi Flegrei Caldera (Italy) during Volcanic Unrest in the Period 2011–2017. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11135809] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The study concerns the analysis of 220Rn (thoron) recorded in the surface soil in two sites of the Campi Flegrei caldera (Naples, Southern Italy) characterized by phases of volcanic unrest in the seven-year period 1 July 2011–31 December 2017. Thoron comes only from the most surface layer, so the characteristics of its time series are strictly connected to the shallow phenomena, which can also act at a distance from the measuring point in these particular areas. Since we measured 220Rn in parallel with 222Rn (radon), we found that by using the same analysis applied to radon, we obtained interesting information. While knowing the limits of this radioisotope well, we highlight only the particular characteristics of the emissions of thoron in the surface soil. Here, we show that it also shows some clear features found in the radon signal, such as anomalies and signal trends. Consequently, we provide good evidence that, in spite of the very short life of 220Rn compared to 222Rn, both are related to the carrier effect of CO2, which has significantly increased in the last few years within the caldera. The hydrothermal alterations, induced by the increase in temperature and pressure of the caldera system, occur in the surface soils and significantly influence thoron’s power of exhalation from the surface layer. The effects on the surface thoron are reflected in both sites, but with less intensity, the same behavior of 222Rn following the increasing movements and fluctuations of the geophysical and geochemical parameters (CO2 flux, fumarolic tremor, background seismicity, soil deformation). An overall linear correlation was found between the 222−220Rn signals, indicating the effect of the CO2 vector. The overall results represent a significant step forward in the use and interpretation of the thoron signal.
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Devi V, Chauhan RP. Implications on dose estimation and dispersion patterns of thoron in a typical indoor environment. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2021; 60:309-316. [PMID: 33689025 DOI: 10.1007/s00411-021-00899-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 02/20/2021] [Indexed: 06/12/2023]
Abstract
A model that describes the pollutant sources/sinks and inlet-outlet can help to assess the indoor exposure. Short half-life of radioactive thoron (220Rn) makes it vital and an interesting element to study its dispersion behavior. This work presents an extensive depiction of the influence of indoor environment thoron dispersion under fixed boundary conditions within the volume domain of 90 m3 using computational fluid dynamics (CFD) software. For the desirable air flow, inlet and outlet are considered in the room and the k-ɛ model is used. The thoron distribution is studied at different locations and different heights to cover the whole room. Obtained dispersion patterns vary at different locations and indicate non-uniformity of thoron level with elevated values in the room corners. Mean concentration was found to be 11 Bq/m3 with the exhalation rate of 0.102 Bqm-2 s-1. Some stagnant zones were found especially at the corners where the concentration is almost 5 times the average concentration. Such varying thoron level results in the overestimation and underestimation of the dose. The inhomogeneous behavior of thoron may cause variation in equilibrium factor. A simulated model is beneficial in understanding the radioactive gas behavior and has its importance in planning to find the correct dose estimation and, therefore, the best mitigation techniques.
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Affiliation(s)
- Vandana Devi
- Department of Physics, National Institute of Technology, Kurukshetra, Haryana, 136119, India
| | - R P Chauhan
- Department of Physics, National Institute of Technology, Kurukshetra, Haryana, 136119, India.
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Ambrosino F, Roca V, Buompane R, Sabbarese C. Development and calibration of a method for direct measurement of 220Rn (thoron) activity concentration. Appl Radiat Isot 2020; 166:109310. [DOI: 10.1016/j.apradiso.2020.109310] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Revised: 05/24/2020] [Accepted: 06/22/2020] [Indexed: 10/23/2022]
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An Improved Passive CR-39-Based Direct 222Rn/ 220Rn Progeny Detector. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17228569. [PMID: 33218216 PMCID: PMC7699185 DOI: 10.3390/ijerph17228569] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 11/16/2020] [Accepted: 11/16/2020] [Indexed: 11/17/2022]
Abstract
An improved passive CR-39-based direct 222Rn/220Rn progeny detector with 3 detection channels was designed and tested in this study to measure and calculate equilibrium equivalent concentration (EEC) of both 222Rn and 220Rn without the equilibrium factor. A theoretical model was established to calculate the EEC with optimization. Subsequently, an exposure experiment was carried out to test the performance of this detector, and we compared the chamber experiment and the theoretical model by estimating and measuring various parameters. The deposition flux of progeny derived from the prediction agreed well with the value measured in the exposure chamber. The energy-weighted net track density (NTD) measured by this detector is much more reliable to reflect the linear relation between NTD and time-integrated EEC. Since the detector is sensitive to the exposure environmental condition, it is recommended to apply the detector to measure the EEC after its calibration in a typical indoor environment.
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Ye Y, Chung LK, Zhou Q, Kearfott KJ. Evaluation of 222Rn and 220Rn discriminating concentration measurements with pinhole-based twin cup dosimeters using computational fluid dynamics simulations. RADIAT MEAS 2020. [DOI: 10.1016/j.radmeas.2020.106369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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