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Your search keyword '"Hosoda, Masahiro"' showing total 14 results
Start Over Author "Hosoda, Masahiro" Journal international journal of environmental research and public health
14 results on '"Hosoda, Masahiro"'

2. 222Rn and 226Ra Concentrations in Spring Water and Their Dose Assessment Due to Ingestion Intake

Author

Yamada, Ryohei, primary, Hosoda, Masahiro, additional, Tabe, Tomomi, additional, Tamakuma, Yuki, additional, Suzuki, Takahito, additional, Kelleher, Kevin, additional, Tsujiguchi, Takakiyo, additional, Tateyama, Yoshiki, additional, Nugraha, Eka Djatnika, additional, Okano, Anna, additional, Narumi, Yuki, additional, Kranrod, Chutima, additional, Tazoe, Hirofumi, additional, Iwaoka, Kazuki, additional, Yasuoka, Yumi, additional, Akata, Naofumi, additional, Sanada, Tetsuya, additional, and Tokonami, Shinji, additional

Published
2022
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3. Passive-Type Radon Monitor Constructed Using a Small Container for Personal Dosimetry

Author

Tamakuma, Yuki, Kranrod, Chutima, Suzuki , Takahito, Watanabe, Yuki, Ploykrathok, Thamaborn, Negami , Ryoju, Djatnika Nugraha, Eka, Iwaoka, Kazuki, Mirosław, Janik, Hosoda, Masahiro, Tokonami, Shinji, Kazuki, Iwaoka, and Janik, Miroslaw

Subjects
respiratory tract diseases
Abstract

The International Commission on Radiological Protection (ICRP) recently recommended a new dose conversion factor for radon based on the latest epidemiological studies and dosimetric model. It is important to evaluate an inhalation dose from radon and its progeny. In the present study, a passive radon personal monitor was designed using a small container for storing contact lenses and its performance was evaluated. The conversion factor for radon (222Rn), the effect of thoron (220Rn) concentration and the air exchange rate were evaluated using the calibration chamber at Hirosaki University. The minimum and maximum detectable radon concentrations were calculated. The conversion factor was evaluated as 2.0 ± 0.3 tracks cm−2 per kBq h m−3; statistical analyses of results showed no significant effect from thoron concentration. The minimum and maximum detectable radon concentrations were 92 Bq m−3 and 231 kBq m−3 for a measurement period of three months, respectively. The air exchange rate was estimated to be 0.26 ± 0.16 h−1, whose effect on the measured time-integrated radon concentration was small. These results indicate that the monitor could be used as a wearable monitor for radon measurements, especially in places where radon concentrations may be relatively high, such as mines and caves.

Published
2020

5. Temporal and Spatial Variation of Radon Concentrations in Environmental Water from Okinawa Island, Southwestern Part of Japan

Author

Nakasone, Shunya, primary, Ishimine, Akinobu, additional, Shiroma, Shuhei, additional, Masuda, Natsumi, additional, Nakamura, Kaori, additional, Shiroma, Yoshitaka, additional, Ooka, Sohei, additional, Tanaka, Masahiro, additional, Kato, Akemi, additional, Hosoda, Masahiro, additional, Akata, Naofumi, additional, Yasuoka, Yumi, additional, and Furukawa, Masahide, additional

Published
2021
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6. Discriminative Measurement of Absorbed Dose Rates in Air from Natural and Artificial Radionuclides in Namie Town, Fukushima Prefecture

Author

Ogura, Koya, primary, Hosoda, Masahiro, additional, Tamakuma, Yuki, additional, Suzuki, Takahito, additional, Yamada, Ryohei, additional, Negami, Ryoju, additional, Tsujiguchi, Takakiyo, additional, Yamaguchi, Masaru, additional, Shiroma, Yoshitaka, additional, Iwaoka, Kazuki, additional, Akata, Naofumi, additional, Shimizu, Mayumi, additional, Kashiwakura, Ikuo, additional, and Tokonami, Shinji, additional

Published
2021
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13. 222 Rn and 226 Ra Concentrations in Spring Water and Their Dose Assessment Due to Ingestion Intake.

Author

Yamada R, Hosoda M, Tabe T, Tamakuma Y, Suzuki T, Kelleher K, Tsujiguchi T, Tateyama Y, Nugraha ED, Okano A, Narumi Y, Kranrod C, Tazoe H, Iwaoka K, Yasuoka Y, Akata N, Sanada T, and Tokonami S

Subjects
Background Radiation, Eating, Radiation Dosage, Water Supply, Drinking Water analysis, Radiation Monitoring, Radon analysis, Water Pollutants, Radioactive analysis
Abstract

222 Rn and 226 Ra concentrations of less than a few to several thousands of Bq L - 1 have been observed in several underground bodies of water around the world. Although regulations for these concentrations in water have been implemented internationally, there are currently no regulations in place in Japan. However, concentrations that exceed these internationally recognized regulatory values have also been observed in Japan. In this study, concentrations in spring water in the northern part of Japan were measured and the effective dose from intake of the water was evaluated. 222 Rn concentrations were measured using a liquid scintillation counter, and 226 Ra concentrations were measured using a high purity germanium detector after chemical preparation. The measured 222 Rn concentrations (=12.7 ± 6.1 Bq L -1 ) and 226 Ra concentrations (<0.019-0.022 Bq L -1 ) did not exceed the reference values set by international and European/American organizations. A conservative estimate of the annual effective ingestion dose of 8 μSv for 222 Rn and 226 Ra obtained in this study is much smaller than the estimated overall annual effective dose of 2.2 mSv from natural radiation to the Japanese population. However, this dosage accounts for 8% of the WHO individual dosing criteria of 0.1 mSv/year for drinking water.

Published
2022
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14. An Improved Passive CR-39-Based Direct 222 Rn/ 220 Rn Progeny Detector.

Author

Hu J, Yang G, Kranrod C, Iwaoka K, Hosoda M, and Tokonami S

Subjects
Polyethylene Glycols, Radon Daughters analysis, Air Pollutants, Radioactive analysis, Air Pollution, Indoor analysis, Radiation Monitoring instrumentation, Radon analysis
Abstract

An improved passive CR-39-based direct 222 Rn/ 220 Rn progeny detector with 3 detection channels was designed and tested in this study to measure and calculate equilibrium equivalent concentration (EEC) of both 222 Rn and 220 Rn 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.

Published
2020
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