A model comparison of diffusion-controlled radon exhalation from solid and cavity walls with application to high backgro
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SHORT RESEARCH AND DISCUSSION ARTICLE
A model comparison of diffusion-controlled radon exhalation from solid and cavity walls with application to high background radiation areas Yanliang Tan 1
&
Hongzhi Yuan 1 & Kimberlee Kearfott 2
Received: 4 May 2020 / Accepted: 15 September 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Radon exhaled from building material surfaces is an important source of indoor radon. Yangjiang, located in the southern part of mainland China, is well-known as a high background radiation area (HBRA). Rather, high levels of radon and thoron concentration have been observed in adobe and brick houses. Reducing the indoor radon concentration remains an important issue in the high background radiation areas of China and the world. Generally, the walls of Chinese dwellings are solid. In this paper, a simple one-dimensional model for predicting the radon diffusion in a cavity wall is proposed, and an analysis formula describing the radon exhalation rate from cavity wall surfaces is presented. The influence on the radon exhalation rate due to leakage through structural joints and building material cracks is analyzed. The simulation results indicate that the radon exhalation rate from a cavity wall surface is far lower than that from a solid wall. The structure of cavity walls themselves is therefore useful as a mechanism for reducing the indoor radon in high background radiation areas across the world. Keywords Radon diffusion . Radon exhalation rate . Cavity wall . Solid wall . Indoor radon
Introduction Radon (Rn-222) is a chemically inert and odorless radioactive gas from the uranium (U-238) decay chain. It is ubiquitous in rocks and soils worldwide, and has become a significant indoor air pollutant (Ivanova et al. 2019; Park et al. 2018; Fontanella et al. 2015; Yuness et al. 2016; Ravikumar and Somashekar 2014;). It is hazardous to occupational workers and human health (Bekteshi et al. 2017; Navrátilová Rovenská et al. 2015.). Generally, most radon emanate from soil, but the radon exhaled from building material surfaces is also an important source of indoor radon (Sahoo et al. 2011). The contribution of building materials to indoor radon Responsible Editor: Georg Steinhauser * Yanliang Tan [email protected] 1
College of Physics and Electronic Engineering, Hengyang Normal University, Hengyang, Hunan, China
2
Department of Nuclear Engineering and Radiological Sciences, The University of Michigan, Ann Arbor, MI, USA
concentration depends upon the radon exhalation rates (Kumar et al. 2014). Based on the application of the diffusion principle, radon exhalation rates from building material surfaces depend on several parameters, specifically the radium content, the emanation rate of radon, and the radon diffusion length. Generally, the walls of Chinese dwellings are built using solid bricks. The radionuclides in building materials in China are limited by a published national standard (GB 6566-2010, 2010). For primary building materials, the maximum permitted value of the
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