## 3 Results and Discussion  
### Qualitative Composition of the VOCs from the Obtained Bio-Based Boards  
A significant number of different VOCs was detected in the tested bio-based boards by HS-SPME-GC-MS analysis. Tables 2-5 summarize the main identified chemical compounds. To simplify the tables, only compounds with >0.5% peak area are shown. Differences between RI values obtained experimentally and found in the literature can be explained by small differences between the used chromatographic parameters and differences in the used column stationary phases. Figure 1: Weighed board specimens in closed vials. \begin{table}
\begin{tabular}{l c c c c c c} \hline \hline
**Compound** & **RI\({}_{\text{lit}}\)[24]** & **RI\({}_{\text{exp}}\)** & **GA 700** & **GA 1300** & **B 700** & **B 1300** \\ \hline Acetic acid & 580–660 & 666 & 47.3 \(\pm\) 6.1 & 61.9 \(\pm\) 4.6 & 45.9 \(\pm\) 9.4 & 42.3 \(\pm\) 6.2 \\ Furfural & 782–847 & 854 & 31.6 \(\pm\) 10.0 & 29.9 \(\pm\) 5.2 & 31.8 \(\pm\) 8.2 & 51.3 \(\pm\) 6.6 \\ \(\gamma\)-butyrolactone & 861–914 & 940 & \textless{}0.5 & 0.6 \(\pm\) 0.3 & 1.0 \(\pm\) 0.4 & \textless{}0.5 \\ \(\gamma\)-methylfurfural & 976–990 & 979 & 3.6 \(\pm\) 0.5 & 1.6 \(\pm\) 0.3 & 4.2 \(\pm\) 0.3 & 0.7 \(\pm\) 0.2 \\ \hline Summed area (peak number) & – & – & 82.5 (3/42) & 93.6 (4/41) & 82.9 (4/31) & 94.0 (3/30) \\ \hline \hline \end{tabular}
\end{table} 
Table 4: The most abundant identified VOCs and their relative area % from the total peaks in SPME-GC-MS chromatograms of the woody biomass binder-less boards. \begin{table}
\begin{tabular}{l c c c c c c} \hline \hline
**Compound** & **RI\({}_{\text{lit}}\)[24]** & **RI\({}_{\text{exp}}\)** & **HS 800-6** & **HS 800-6L** & **HS 800-12** & **HS 1200** \\ \hline Acetic acid & 580–660 & 666 & 16.7 \(\pm\) 1.3 & 34.1 \(\pm\) 5.7 & 10.5 \(\pm\) 4.2 & 28.2 \(\pm\) 4.1 \\ Furfural & 782–847 & 854 & 54.8 \(\pm\) 5.1 & 24.6 \(\pm\) 4.1 & 68.4 \(\pm\) 6.3 & 56.0 \(\pm\) 1.2 \\
2-furanmethanol & 863-880 & 874 & 2.5 \(\pm\) 0.5 & 11.7 \(\pm\) 3.7 & 1.8 \(\pm\) 0.5 & 2.5 \(\pm\) 0.8 \\
1,3-propanediol & 793–820 & 890 & 0.7 \(\pm\) 0.1 & 0.6 \(\pm\) 0.1 & \textless{}0.5 & 1.0 \(\pm\) 0.3 \\ \(\gamma\)-butyrolactone & 908–938 & 940 & 3.8 \(\pm\) 0.1 & 11.8 \(\pm\) 3.3 & 3.8 \(\pm\) 1.5 & 1.7 \(\pm\) 1.0 \\
5-methylfurfural & 976–990 & 979 & 15.6 \(\pm\) 1.4 & 4.0 \(\pm\) 0.8 & 9.9 \(\pm\) 3.2 & 4.7 \(\pm\) 0.1 \\ \hline Summed area (peak number) & – & – & 94.1 (6/66) & 86.8 (6/86) & 94.4 (5/56) & 94.1 (6/99) \\ \hline \hline \end{tabular}
\end{table} 
Table 2: The most abundant identified VOCs and their relative area % from the total peaks in SPME-GC-MS chromatograms of the hemp shives binder-less boards. \begin{table}
\begin{tabular}{l c c c c c} \hline \hline
**Compound** & **RI\({}_{\text{lit}}\)[24]** & **RI\({}_{\text{exp}}\)** & **HS 800-6** & **HS 800-6L** & **HS 800-12** & **HS 1200** \\ \hline Acetic acid & 580–660 & 666 & 16.7 \(\pm\) 1.3 & 34.1 \(\pm\) 5.7 & 10.5 \(\pm\) 4.2 & 28.2 \(\pm\) 4.1 \\ Furfural & 782–847 & 854 & 54.8 \(\pm\) 5.1 & 24.6 \(\pm\) 4.1 & 68.4 \(\pm\) 6.3 & 56.0 \(\pm\) 1.2 \\
2-furanmethanol & 863-880 & 874 & 2.5 \(\pm\) 0.5 & 11.7 \(\pm\) 3.7 & 1.8 \(\pm\) 0.5 & 2.5 \(\pm\) 0.8 \\
1,3-propanediol & 793–820 & 890 & 0.7 \(\pm\) 0.1 & 0.6 \(\pm\) 0.1 & \textless{}0.5 & 1.0 \(\pm\) 0.3 \\ \(\gamma\)-butyrolactone & 908–938 & 940 & 3.8 \(\pm\) 0.1 & 11.8 \(\pm\) 3.3 & 3.8 \(\pm\) 1.5 & 1.7 \(\pm\) 1.0 \\
5-methylfurfural & 976–990 & 979 & 15.6 \(\pm\) 1.4 & 4.0 \(\pm\) 0.8 & 9.9 \(\pm\) 3.2 & 4.7 \(\pm\) 0.1 \\ \hline Summed area (peak number) & – & – & 94.1 (6/66) & 86.8 (6/86) & 94.4 (5/56) & 94.1 (6/99) \\ \hline \hline \end{tabular}
\end{table} 
Table 3: The most abundant identified VOCs and their relative area % from the total peaks in SPME-GC-MS chromatograms of the wheat straw binder-less boards.