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Variable Strength in Thoron Interference for a Diffusion-Type Radon Monitor Depending on Ventilation of the Outer Air

Thoron interference in radon measurements using passive diffusion radon detectors/monitors is a crucial problem when it comes to assessing the internal exposure to radon precisely. The present study reported, as one of the potential factors, the effects of air flow conditions on changes in thoron in...

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Autores principales: Omori, Yasutaka, Shimo, Michikuni, Janik, Miroslaw, Ishikawa, Tetsuo, Yonehara, Hidenori
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7036855/
https://www.ncbi.nlm.nih.gov/pubmed/32033235
http://dx.doi.org/10.3390/ijerph17030974
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author Omori, Yasutaka
Shimo, Michikuni
Janik, Miroslaw
Ishikawa, Tetsuo
Yonehara, Hidenori
author_facet Omori, Yasutaka
Shimo, Michikuni
Janik, Miroslaw
Ishikawa, Tetsuo
Yonehara, Hidenori
author_sort Omori, Yasutaka
collection PubMed
description Thoron interference in radon measurements using passive diffusion radon detectors/monitors is a crucial problem when it comes to assessing the internal exposure to radon precisely. The present study reported, as one of the potential factors, the effects of air flow conditions on changes in thoron interference. Rates of thoron infiltration (as thoron interference) into the diffusion chamber of the monitor were evaluated. The temporal variation was obtained based on measurements of the underfloor space of a Japanese wooden dwelling using a diffusion-type radon monitor, a reference radon monitor which was not affected by thoron interference, and a thoron monitor. The thoron infiltration rate for the diffusion-type monitor varied from 0% to 20%. In particular, it appeared to increase when ventilation of the underfloor space air was forced. The variable thoron infiltration rate, with respect to ventilation strength, implied that not only a diffusive process, but also an advective process, played a major role in air exchange between the diffusion chamber of the monitor and the outer air. When an exposure room is characterized by the frequent variation in air ventilation, a variable thoron response is considered to occur in radon–thoron discriminative detectors, in which only diffusive entry is employed as a mechanism for the discrimination of radon and thoron.
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spelling pubmed-70368552020-03-11 Variable Strength in Thoron Interference for a Diffusion-Type Radon Monitor Depending on Ventilation of the Outer Air Omori, Yasutaka Shimo, Michikuni Janik, Miroslaw Ishikawa, Tetsuo Yonehara, Hidenori Int J Environ Res Public Health Article Thoron interference in radon measurements using passive diffusion radon detectors/monitors is a crucial problem when it comes to assessing the internal exposure to radon precisely. The present study reported, as one of the potential factors, the effects of air flow conditions on changes in thoron interference. Rates of thoron infiltration (as thoron interference) into the diffusion chamber of the monitor were evaluated. The temporal variation was obtained based on measurements of the underfloor space of a Japanese wooden dwelling using a diffusion-type radon monitor, a reference radon monitor which was not affected by thoron interference, and a thoron monitor. The thoron infiltration rate for the diffusion-type monitor varied from 0% to 20%. In particular, it appeared to increase when ventilation of the underfloor space air was forced. The variable thoron infiltration rate, with respect to ventilation strength, implied that not only a diffusive process, but also an advective process, played a major role in air exchange between the diffusion chamber of the monitor and the outer air. When an exposure room is characterized by the frequent variation in air ventilation, a variable thoron response is considered to occur in radon–thoron discriminative detectors, in which only diffusive entry is employed as a mechanism for the discrimination of radon and thoron. MDPI 2020-02-04 2020-02 /pmc/articles/PMC7036855/ /pubmed/32033235 http://dx.doi.org/10.3390/ijerph17030974 Text en © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Omori, Yasutaka
Shimo, Michikuni
Janik, Miroslaw
Ishikawa, Tetsuo
Yonehara, Hidenori
Variable Strength in Thoron Interference for a Diffusion-Type Radon Monitor Depending on Ventilation of the Outer Air
title Variable Strength in Thoron Interference for a Diffusion-Type Radon Monitor Depending on Ventilation of the Outer Air
title_full Variable Strength in Thoron Interference for a Diffusion-Type Radon Monitor Depending on Ventilation of the Outer Air
title_fullStr Variable Strength in Thoron Interference for a Diffusion-Type Radon Monitor Depending on Ventilation of the Outer Air
title_full_unstemmed Variable Strength in Thoron Interference for a Diffusion-Type Radon Monitor Depending on Ventilation of the Outer Air
title_short Variable Strength in Thoron Interference for a Diffusion-Type Radon Monitor Depending on Ventilation of the Outer Air
title_sort variable strength in thoron interference for a diffusion-type radon monitor depending on ventilation of the outer air
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7036855/
https://www.ncbi.nlm.nih.gov/pubmed/32033235
http://dx.doi.org/10.3390/ijerph17030974
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