## 3 Results and Discussion
### Converted Doses  
Supplementary Figure S1 provides insights into various stone materials sourced from different regions, focusing on their exposure to gamma radiation and radon/thoron exhalation. These factors contribute significantly to the total effective radiological dose.  
The dataset includes a wide range of stone types from Ireland, other EU countries, and non-EU sources.  
The total annual effective dose and the I index, which indicates radiation hazard levels, show considerable variation among these materials. Notably, in the worst-case scenario, the highest total annual effective dose recorded for Irish-origin materials comes from granite sourced in the Galway region, with a dose of 3.90 mSv and an I index of 0.29 mSv, highlighting its significant radiological importance.  
The accompanying figure illustrates the contributions of gamma radiation and radon/thoron exhalation rates for samples that had the highest dose contributions.  
In the tested samples, which originate from Ireland, gamma radiation contributes between 0.17 mSv and 0.40 mSv to the total effective dose, accounting for about 7% to 33% of the overall exposure. In contrast, radon and thoron exhalation play a much more substantial role, contributing between 0.01 mSv and 3.61 mSv--approximately 7% to 93% of the total effective dose (Figure 5). These data underscore that for the measured samples, radon and thoron are the primary sources of radiation exposure in Irish samples, while gamma radiation acts as a secondary contributor.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**D230A**} & \multicolumn{4}{c}{**GT-40**} \\ \cline{2-5}  & **Dose Rate (DR) nSv/h** & **U [mg/kg]** & **Th [mg/kg]** & **K [\%]** \\ \hline DR & 0.73 & & & \\ U & & 0.53 & & \\ Th & & & 0.79 & \\ K & & & & 0.50 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Cross-validation of dose rate (DR) uranium (U), thorium (Th), and potassium (K) collected using a GT40 hand-held gamma detector with those measured during the drone-borne surveys using a D230A gamma detector.  
Figure 5: Contributions to the total effective dose (dose from gamma radiation plus dose from radon and thoron exhalations).  
For the samples tested, which originated within the EU (but excluding Ireland), gamma radiation contribution ranges from 0.18 mSv to 0.20 mSv, making up about 15% to 32% of the total dose. The total annual effective dose for these samples varies from 0.18 mSv to 0.68 mSv, with radon and thoron doses ranging from 0.00 mSv to 0.46 mSv, contributing roughly 0% to 85% of the total dose. This re-emphasizes that while gamma radiation constitutes a modest fraction of the total dose in EU samples, radon and thoron remain the more significant contributors.  
For the tested samples, which originated from outside the EU, gamma radiation contributes between 0.16 mSv and 0.19 mSv, accounting for about 9% to 44% of the total dose. The total annual effective dose ranges from 0.17 mSv to 2.22 mSv, with radon and thoron contributions varying from 0.00 mSv to 2.03 mSv--representing approximately 56% to 91% of the total dose. This variation highlights the diverse impact of gamma radiation across non-EU samples, where radon and thoron generally emerge as the predominant sources of overall radiation exposure.