## 3 Results and Discussion  
### IAQ Assessment  
After the experimental indoor environments was established, IAQ was measured. IAQ can directly affect the health and living conditions of occupants who spend extended periods indoors, necessitating thorough analysis.  
Considering the potential side effects of IAQ on both the experimental environments and human health, this study conducted a comparative analysis based on the guidelines stipulated by the Korean Ministry of Environment's Indoor Air Quality Control Act. The parameters and threshold values specified in the recommended guidelines are listed below (Table 1): particulate matter with a diameter of 10 \(\mu\)g or less (PM10 75 \(\mu\)g/m\({}^{3}\)), particulate matter with a diameter of 2.5 \(\mu\)g or less (PM2.5 35 \(\mu\)g/m\({}^{3}\)), carbon monoxide (CO 10 ppm), carbon dioxide (CO\({}_{2}\) 1000 ppm), formaldehyde (HCHO 85 \(\mu\)g/m\({}^{3}\)), total airborne bacteria (800 CFU/m\({}^{3}\)), volatile organic compounds (VOCs 400 \(\mu\)g/m\({}^{3}\)), nitrogen oxide (NOx 0.05 ppm), fungi (500 CFU/m\({}^{3}\)), and radon (148 Bq/m\({}^{3}\)).  
As seen in the results, all measured values of three indoor environments satisfied the threshold stipulated in the Indoor Air Quality Control Act by the Ministry of Environment. Meanwhile, the VOC levels in the wooden indoors (61.7-159.9 \(\mu\)g/m\({}^{3}\)) were lower than in the non-wood indoors (349.3 \(\mu\)g/m\({}^{3}\)) (Table 1). Volatile organic compounds can be classified into naturally occurring and artificially generated substances. Although wood is generally known to emit natural volatile organic compounds (VOCs) such as terpen, the higher VOC concentrations were observed in the non-wooden indoors (0%) in this study. We hypothesize that this is attributable to the adhesives used in the finishing materials, such as the wallpaper, of the non-wooden indoors.  
Currently, in Korea, the \"interior wood-based remodeling\" policy initiative is being promoted to encourage the use of wood in welfare facility interiors such as daycare centers and hospitals. [PERSON] et al. evaluated 12 IAQ indicators at the wood-based remodeling project sites and reported that the measured values satisfied the international IAQ guidelines. They suggested that the establishment of wooden indoor environments contributes to the improvement of IAQ [15].  
The BTEXs listed in Table 2 are particularly hazardous VOCs that are separately regulated due to their high toxicity, and are included in the recommended IAQ standards  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Factor**} & \multirow{2}{*}{**Measurement Range *} & \multicolumn{3}{c}{**Wood Cover Rate (\%)**} \\ \cline{3-5}  & & **0** & **45** & **90** \\ \hline PM10 (\(\mu\)g/m\({}^{3}\)) & 75 & 18.7 & 18.4 & 17.6 \\ PM2.5 (\(\mu\)g/m\({}^{3}\)) & 35 & 7.2 & 5.1 & 4.3 \\ CO (ppm) & 10 & 2.2 & 2.1 & 1.7 \\ HCHO (\(\mu\)g/m\({}^{3}\)) & 80 & 18.6 & 16.1 & 17.4 \\ CO2 (ppm) & 1000 & 546 & 548 & 512 \\ Total airborne bacteria (CFU/m\({}^{3}\)) & 800 & 150 & 83 & 43 \\ VOC (\(\mu\)g/m\({}^{3}\)) & 400 & 349.3 & 159.9 & 61.7 \\ NOx (ppm) & 0.05 & 0.014 & 0.015 & 0.001 \\ Fungi (CFU/m\({}^{3}\)) & 500 & 31 & 33 & 25 \\ Rn (Bq/m\({}^{3}\)) & 148 & 13.0 & 14.0 & 17.0 \\ \hline \hline \end{tabular}  
* \({}^{*}\)Thresholds stipulated in the IAQ Control Act by the Korean Ministry of Environment.  
\end{table}
Table 1: Mean values of IAQ indicators in wooden and non-wooden environments.  
for newly built residential buildings in Korea. The results of this study showed that the BTEX concentrations in all three environments met the recommended thresholds.