## 3 Data Collection for the Case Study of Natural Carbonation
### Data Description of Environmental Conditions  
Regional environmental data were collected to analyze the environmental impacts of carbonation. The carbonation of concrete was affected by the mixing ratio, moisture ratio, curing period, and long-term environmental changes. In this study, regional environmental data were collected considering the long-term changes in carbonation. The environmental data were extracted from the national meteorological database of Korea [44]. The collected environmental data were organized with respect to year and region. The data were collected from 1940 to 2021, and 492 data points were collected for each region. Table 3 and Figure 5 present the environmental conditions data for each region. The collected environmental data comprised the annual average temperature, daily temperature difference, precipitation, relative humidity, carbon dioxide, and number of snowy days. The average temperature, daily temperature difference, precipitation, humidity, and carbon dioxide directly influence carbonation. The number of snowy days was included because chloride penetration by deicing agents is known to accelerate carbonation. In Korea, the carbon dioxide concentration is used as a single carbon dioxide concentration index.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Classification** & **Factors** & **Average** & **Min** & **Max** \\ \hline \multirow{6}{*}{Indirect factors} & Width & 18.87 & 4 & 61.48 \\ \cline{2-5}  & Height & 6.67 & 2 & 29.5 \\ \cline{2-5}  & Loading condition for design & 22.08 & 13.5 & 24 \\ \cline{2-5}  & Element position & & 0 & 1 \\  & (superstructure and substructure) & - & (superstructure) & (substructure) \\ \hline Carbonation & Carbonation depth & 10.510 & 2 & 40 \\ \hline \hline \end{tabular}
\end{table}
Table 2: _Cont._  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Classification** & **Factors** & **Region** & **Average** & **Min** & **Max** \\ \hline \multirow{6}{*}{Temperature (\({}^{\circ}\)C)} & \multirow{3}{*}{Average temperature} & A & 12.1 & 9.6 & 13.8 \\ \cline{3-6}  & & B & 13.6 & 12.2 & 14.8 \\ \cline{3-6}  & & C & 15.5 & 13.9 & 17.5 \\ \cline{2-6}  & & A & 9.0 & 7.8 & 11.4 \\ \cline{3-6}  & Daily temperature difference & B & 17.5 & 12.8 & 20.5 \\ \cline{3-6}  & & C & 3.4 & 2.9 & 4 \\ \hline \multirow{6}{*}{Humidity} & \multirow{3}{*}{Relative humidity} & A & 66.4 & 56.6 & 73.6 \\ \cline{3-6}  & & B & 66.8 & 61 & 72 \\ \cline{3-6}  & & C & 71.7 & 61.8 & 79.8 \\ \hline \multirow{6}{*}{Carbon dioxide} & \multirow{3}{*}{Carbon dioxide concentration} & A & & & \\ \cline{3-6}  & & B & 327.5 & 233.5 & 421.4 \\ \cline{3-6}  & & C & & & \\ \hline \multirow{6}{*}{Precipitation} & \multirow{3}{*}{Precipitation} & A & 1344.9 & 623.5 & 2355.5 \\ \cline{3-6}  & & B & 1431.7 & 819.3 & 2195.5 \\ \cline{3-6}  & & C & 1465.9 & 773.3 & 2526 \\ \hline \multirow{6}{*}{Chloride penetration} & \multirow{3}{*}{Number of snowy days} & A & 27.1 & 3 & 50 \\ \cline{3-6}  & & B & 6.6 & 0 & 21 \\ \cline{3-6}  & & C & 22.0 & 5 & 44 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Environmental conditions data for each region.