## 3 Results
### Embedded Toxicity
\begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline \multicolumn{1}{c}{\multirow{2}{*}{**VOC Emitted**}} & \multirow{2}{*}{**CAS No.**} & \multirow{2}{*}{**N/I**} & \multicolumn{8}{c}{**Sample Specific Concentrations**} \\ \cline{4-14}  & & & & \multicolumn{8}{c}{**(ppm\({}_{\text{m}}\) Material)**} & \\ \cline{4-14}  & & & **1** & **2** & **3** & **4** & **5** & **6** & **7** & **8** & **9** & **10** \\ \hline
1-Heptene & 592-76-7 & I & - & 3.69 & 9.70 & 299.64 & 16.53 & 5.71 & 3.66 & 3.28 & 3.71 & 19.77 \\ \hline
2,4-Hexadieneoic acid & 110-44-1 & I & - & 4.94 & - & - & - & - & - & - & - & - \\ \hline
3-Heptene-2,6-dione & 99809-46-8 & I & - & 6.20 & - & - & - & - & - & - & - \\ \hline Benzaldehyde \({}^{*}\) & 100-52-7 & I & 99.25 & - & - & 62.50 & 6.07 & 22.44 & 33.51 & 27.34 & 2.35 & 1.44 \\ \hline Benzene \({}^{*}\) & 71-43-2 & I & 21.95 & 22.95 & 19.19 & 13.35 & 27.50 & 14.76 & 8.21 & 9.47 & 1.91 & 0.80 \\ \hline Decane & 124-18-5 & I & 1663.3 & 93.01 & 360.91 & 171.70 & 42.39 & 232.90 & 45.00 & 179.29 & 3.41 & 14.21 \\ \hline Hexane \({}^{*}\) & 110-54-3 & I & - & 1.26 & - & - & - & - & - & - & - \\ \hline Naphthalene \({}^{*}\) & 91-20-3 & I & - & - & 26.41 & 188.35 & 26.07 & 81.88 & - & - & 8.86 & - \\ \hline Pyridine \({}^{*}\) & 110-86-1 & I & 41.01 & - & - & - & - & - & - & - & - \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Identified VOCs emitted from 10 samples of recycled concrete, with CAS no., origin (N = naturally occurring/I = incorporated chemical) and concentration in ppm\({}_{\text{m}}\). \({}^{*}\) denotes the characterized chemicals. Figure 5 indicates the mass share of chemicals per kg material that could be characterized relative to the total amount of identified chemicals. In 1 kg of concrete, it was possible to characterize on average 45% of the chemicals: 21% naphthalene, 13% benzaldehyde, 10% benzene, 1% hexane, and <1% pyridine. The reason why more naphthalene is extracted from concrete compared to the other chemicals could be twofold. First, naphthalene is less volatile compared to e.g., benzene, which is indicated by the vapor pressures and Henry's law constants [37] of the two compounds (please see Appendix A Tables A1 and A2). The low volatility causes naphthalene to remain \"trapped\" and persists longer in the building materials analyzed relative to more-volatile compounds like benzene. Secondly, the elevated temperature applied during the thermal stripping of materials may have resulted in a naphthalene (burst) release. In 1 kg of wood, only naphthalene could be characterized using the available characterization factors, representing on average only 4% of the chemicals detected in wood. For both wood and concrete, the fraction of chemicals identified and quantified in the experimental setup that could not be characterized is considerable. This non-characterizable fraction of chemicals could play a decisive role when assessing the toxicity of building materials since these chemicals cannot be accounted for and thus, apart from a potential direct accounting of mass with relation to the impact assessment, are disregarded. Figure 4: The average embedded toxicity impact per kg building material is given in DALY with a standard deviation. The standard deviation for the average embedded toxicity impact of concrete is very large compared to that of wood, which is due to the large impact variation between the samples of concrete. Figure 5: The average mass share (in %) of identified and characterized chemicals per kg building material. In concrete, 45% of the identified chemicals could be characterized, including 21% naphthalene, 13% benzaldehyde, 10% benzene, 1% hexane and <1% pyridine. In the wood samples, only naphthalene could be characterized, which comprised 4% of the identified chemicals.