## 3 Results and Discussion
### Health Risk Assessment  
Starting with BaPE values, the average of 1.27 \(\mathrm{ng}\)\(\mathrm{m}^{-3}\) indicates increased toxicity of the particulate matter due to BaP related PAHs. The values were lower during the warm period (0.57 \(\mathrm{ng}\)\(\mathrm{m}^{-3}\)) and \begin{table}
\begin{tabular}{c c c c} \hline \hline  & **PC1** & **PC2** & **PC3** \\ \hline Explained Variance & 36.2\% & 24.3\% & 22.9\% \\ NAP & \(-\)0.399 & 0.329 & \(-\)0.213 \\ ACY & \(-\)0.223 & \(-\)0.258 & 0.114 \\ ACE & 0.330 & 0.307 & \(-\)0.205 \\ FL & \(-\)0.198 & 0.210 & 0.763 \\ PHE & \(-\)0.027 & \(-\)0.048 & 0.805 \\ ANT & 0.439 & \(-\)0.077 & \(-\)0.260 \\ FLT & 0.116 & 0.204 & 0.893 \\ PYR & 0.132 & 0.370 & 0.848 \\ CHR & 0.755 & 0.420 & 0.525 \\ BaA & 0.729 & 0.398 & 0.501 \\ BbkF & 0.759 & 0.182 & 0.491 \\ BaP & 0.805 & 0.026 & \(-\)0.005 \\ IPY & 0.821 & 0.124 & 0.448 \\ DBAA & 0.534 & 0.340 & 0.748 \\ BPE & 0.808 & 0.112 & 0.433 \\
1,2,3,7,8- PeCDD & 0.314 & 0.287 & 0.056 \\
1,2,3,4,7,8- HxCDD & 0.785 & \(-\)0.119 & 0.444 \\
1,2,3,6,7,8- HxCDD & \(-\)0.362 & \(-\)0.029 & 0.338 \\
1,2,3,7,8,9- HxCDD & \(-\)0.173 & \(-\)0.388 & 0.345 \\
1,2,3,4,6,7,8- HpCDD & 0.768 & 0.268 & 0.015 \\ OCDD & 0.131 & 0.064 & \(-\)0.580 \\
2,3,7,8- TCDF & 0.664 & \(-\)0.362 & \(-\)0.080 \\
1,2,3,7,8- PeCDF & 0.788 & \(-\)0.227 & \(-\)0.023 \\
2,3,4,7,8- PeCDF & 0.772 & 0.499 & \(-\)0.174 \\
1,2,3,4,7,8- HxCDF & 0.815 & \(-\)0.070 & \(-\)0.161 \\
1,2,3,6,7,8- HxCDF & 0.743 & 0.554 & \(-\)0.018 \\
2,3,4,6,7,8- HxCDF & 0.879 & 0.234 & \(-\)0.135 \\
1,2,3,7,8,9- HxCDF & 0.622 & 0.531 & \(-\)0.044 \\
1,2,3,4,6,7,8- HpCDF & 0.889 & 0.180 & \(-\)0.104 \\
1,2,3,4,7,8,9- HpCDF & 0.497 & \(-\)0.106 & 0.182 \\ OCCP & \(-\)0.087 & 0.040 & \(-\)0.452 \\ PCB-77 & 0.270 & 0.113 & 0.082 \\ PCB-81 & \(-\)0.069 & \(-\)0.251 & 0.010 \\ PCB-126 & 0.079 & 0.779 & 0.223 \\ PCB-169 & 0.132 & 0.600 & 0.570 \\ PCB-105 & \(-\)0.049 & 0.313 & \(-\)0.360 \\ PCB-118 & \(-\)0.062 & 0.583 & \(-\)0.388 \\ PCB-123 & \(-\)0.201 & 0.686 & \(-\)0.184 \\ PCB-156 & 0.169 & 0.720 & 0.128 \\ PCB-157 & 0.286 & 0.706 & 0.234 \\ PCB-167 & \(-\)0.067 & \(-\)0.489 & \(-\)0.055 \\ PCB-189 & \(-\)0.082 & 0.455 & 0.294 \\ PCB-28 & 0.108 & 0.384 & \(-\)0.630 \\ PCB-52 & 0.238 & 0.717 & \(-\)0.269 \\ PCB-101 & \(-\)0.266 & 0.473 & \(-\)0.472 \\ PCB-138 & \(-\)0.010 & 0.838 & \(-\)0.236 \\ PCB-153 & 0.163 & 0.832 & 0.216 \\ PCB-180 & \(-\)0.238 & 0.651 & 0.299 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Principal component analysis in the whole sampling campaign. are in agreement with our previous study in the area with values ranging from 0.14-4.6 ng m\({}^{-3}\). Average \(\Sigma\)BaP\({}_{\text{TEQ}}\) in our study was found to be 2.29 ng m\({}^{-3}\) (cold: 2.76 ng m\({}^{-3}\), warm: 0.58 ng m\({}^{-3}\)), lower than in Aspropirgos (7.0 ng m\({}^{-3}\) in autumn and 3.8 ng m\({}^{-3}\) in winter months) [32], but higher than in Thessaloniki (1.5 ng m\({}^{-3}\)) [42]. Similar values were presented in Mestre, Venice with a BaP\({}_{\text{TEQ}}\) value of 3.6 ng m\({}^{-3}\) during winter and 1.7 ng m\({}^{-3}\) in autumn months [77]. Parallel seasonal patterns were calculated for \(\Sigma\)BaP\({}_{\text{MEQ}}\) with an average value of 1.61 ng m\({}^{-3}\) (cold: 1.89 ng m\({}^{-3}\), warm: 0.59 ng m\({}^{-3}\)). As it is clear from Figure 9, the cold period was strongly associated with increased toxicity of aerosol due to PAHs levels. ICR, due to the toxicity of PAHs bound to PM\({}_{10}\), was calculated with a mean value of \(2.6\times 10^{-6}\) and \(3.0\times 10^{-6}\) during the cold period and \(1.1\times 10^{-6}\) during the warm period. ICR in Eleusis was higher than that calculated in Thessaloniki (1.6-1.7 \(\times 10^{-6}\) during winter) [42], but in the same level with previous work in Thessaloniki with a value of \(2.8\times 10^{-6}\)[78]. According to USEPA health risk evaluation procedure, the cancer risk from the investigated substances was calculated, and the total cancer risk from POPs in Eleusis was \(3.6\times 10^{-5}\) (Table 6).