# The Relationship between Radon and Geology: Sources, Transport and Indoor Accumulation
## 2 The Origin of Radon
### Accumulation of Radon in Indoor Environments
#### 2.3.6 Rn Accumulation
\begin{table}
\begin{tabular}{c c c} \hline
**Country** & **Rn in Air (Bq\(\cdot\)m\({}^{-3}\))** & **Reference** \\ \hline Australia & 141 \(\pm\) 76 & [PERSON] et al. (2020) \\ \hline Brazil & 227 \(\pm\) 59 & [PERSON] and [PERSON] (2019) \\  & 600 \(\pm\) 787 & [PERSON] et al. (2018) \\ \hline  & 80 \(\pm\) 106 & [PERSON] et al. (2015, 2008) \\ China & 530 & [PERSON] et al. (2006) \\  & 400 & [PERSON] et al. (2008) \\  & 169 & [PERSON] et al. (2016) \\ \hline India & 230 \(\pm\) 66 & [PERSON] et al. (2001) \\ \hline Iran & 321 \(\pm\) 109 & [PERSON] et al. (2002) \\  & 220 & [PERSON] et al. (2006) \\ \hline Pakistan & 192 & [PERSON] et al. (2000) \\  & 89 \(\pm\) 28 & [PERSON] and [PERSON] (2011) \\ \hline  & 609 & [PERSON] and [PERSON] (2002) \\  & 261 & [PERSON] et al. (2022) \\ Poland & 148 \(\pm\) 111 & [PERSON] et al. (2016) \\  & 82 \(\pm\) 6 & [PERSON] et al. (2019) \\  & 67 \(\pm\) 57 & [PERSON] et al. (2021) \\ \hline  & 20 & [PERSON] and [PERSON] (2009) \\ Turkey & 239 & [PERSON] et al. (2010) \\  & 679 \(\pm\) 242 & [PERSON] et al. (2005) \\  & 117 & [PERSON] et al. (2006) \\ \hline \end{tabular}
\end{table} 
Table 5: Results of radon measurements in underground coal mines, as presented by [PERSON] et al. (2023), based on their review of results reported by previous works by [PERSON] et al. (2016), [PERSON] et al. (2001), [PERSON] et al. (2002), [PERSON] et al. (2006), [PERSON] et al. (2000), [PERSON] and [PERSON] (2011), [PERSON] and [PERSON] (2002), [PERSON] et al. (2022), [PERSON] et al. (2016), [PERSON] et al. (2019), [PERSON] et al. (2021), [PERSON] and [PERSON] (2009), [PERSON] et al. (2010), [PERSON] et al. (2005) and [PERSON] et al. (2006) [99; 100; 101; 102]. 227 \(\pm\) 59 Bq m\({}^{-3}\) to 600 \(\pm\) 787 Bq\(\cdot\)m\({}^{-3}\), which is a significant difference, while Australia has a more consistent but higher mean level of 141 \(\pm\) 76 Bq\(\cdot\)m\({}^{-3}\). Radon levels in India, Iran, and Pakistan are somewhat comparable, averaging around 200-300 Bq\(\cdot\)m\({}^{-3}\). Poland's results show a decrease over time from 609 Bq\(\cdot\)m\({}^{-3}\) in 2002 to 67 \(\pm\) 57 Bq\(\cdot\)m\({}^{-3}\) in 2021, suggesting improvements in mitigation efforts or changes in mining practices. Turkey's measurements range from 20 Bq\(\cdot\)m\({}^{-3}\) to 679 \(\pm\) 242 Bq\(\cdot\)m\({}^{-3}\), reflecting a significant variation, which is potentially due to differences in geological conditions or measurement methods. In general, these results underline the importance of continuous monitoring and control of radon levels in underground mines, considering the health risks associated with radon exposure., They also suggest that factors such as geological conditions, mining practices, and mitigation efforts can significantly influence radon levels in these environments. On the other hand, a previous work presented by [PERSON] (2005) provides an extensive overview of radon's physical characteristics, sources, its transportation in rock, and behaviour in cave environments. The author meticulously discusses the tools utilized for measuring radon concentrations, both active and passive, emphasizing their respective pros and cons for use in caves. An interesting highlight is the regulatory landscape surrounding radon in various countries. These regulations, enacted for radiation protection purposes, are examined in depth, along with recommendations issued by international organizations and materials and methods for implementing these limits. [PERSON] underscores radon's peculiarity as a component of cave atmospheres, noting its potential for studying cave microclimates and other phenomena. However, he also mentions that obtaining reliable information can be challenging due to the multitude of factors influencing radon concentration. A noteworthy point [PERSON] makes is about radon's supposed use in earthquake prediction.