## 3 Results and Discussion
### Atmospheric Deposition
#### 3.2.3 PAHs  
The annual average deposition rates of each PAH measured at the four sites are shown in Table 6 while the seasonal variability is illustrated in Figure 4. Table S8 of the Supplementary Material reports the deposition rates of each PAH by season. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Locations** & **PCDD/Fs** & **Ref.** \\ \hline Aosta & urban sites: 0.6–3.0 & \\ (North-West Italy) & industrial sites: 3.7 & [56] \\ \hline Venice & urban sites: 13–200 & \\ (North-East Italy) & industrial sites: 15–2767 & [21] \\ \hline Mantua a  & urban site: 1.2–4.2 & \\ (North Italy) & industrial site: 1.3–5.1 & [57] \\  & rural area: 1.3–2.7 & \\ \hline Stroncone-Terni & & \\ (Central Italy) & urban site: \textless{}5.0 & [58] \\ \hline Taranto & industrial site: 0.57–45 & \\ (South Italy) & rural sites: 1.6–33 & [59] \\ \hline Melfia  & industrial site: 1.7–2.1 & [32; 60] \\ (South Italy) & rural area: 1.2–2.7 & [61] \\ \hline Belgium & urban site: \textless{}1–12 & [61] \\  & rural area: \textless{}1–3.1 & \\ \hline Germany & urban site: \textless{}0.5–464 & \\  & rural area:7–17 & [62; 63] \\ \hline UK & urban site: \textless{}1–312 & \\  & rural area: 0–517 & [33] \\ \hline Denmark & urban site: 300–31,600 & \\  & rural area: 300–1700 & [64; 65] \\ \hline France & urban site: 100–147 & \\  & rural area: 20–50 & [66] \\ \hline North Latium & urban site: 1.4–7.1 & \\ (Central Italy) & industrial site: 1.4–4.6 & \\  & rural area: 1.4–3.9 & \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Comparison of PCDD/F levels (pg I- TE m\({}^{-2}\) d\({}^{-1}\)) in deposition rates among our values and other studies in different Italian and European locations. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Compound** & **Roccaccia** & \multicolumn{2}{c}{**Rocca**} & \multicolumn{1}{c}{**Allumiere**} & \multicolumn{1}{c}{**[PERSON]**} \\ \hline Benz[a]Anthracene & 3.593 & 4.515 & 6.268 & 2.510 \\ Benzo[b]Fluoranthene & 4.760 & 100.493 & 6.320 & 2.587 \\ Benzo[j]Fluoranthene & 4.995 & 1.538 & 3.403 & 1.538 \\ Benzo[k]Fluoranthene & 3.763 & 1.538 & 3.190 & 3.325 \\ Benzo[a]Pyrene & 5.873 & 2.325 & 3.950 & 2.165 \\ Dibenzo[a,h]Anthracene & 1.553 & 1.538 & 1.538 & 1.538 \\ Dibenzo[a,e]Pyrene & 2.073 & 1.538 & 1.538 & 1.538 \\ Dibenzo[a,h]Pyrene & 1.553 & 1.538 & 1.538 & 1.538 \\ Dibenzo[a,i]Pyrene & 2.323 & 1.538 & 1.538 & 1.538 \\ Dibenzo[a,i]Pyrene & 1.553 & 1.538 & 1.538 & 1.538 \\ Indeno[1,2,3-cd]Pyrene & 4.853 & 1.538 & 2.428 & 1.538 \\ Acenaphthenene & 34.663 & 7.178 & 212.348 & 11.710 \\ Acenaphthylene & 36.023 & 9.028 & 18.228 & 16.213 \\ Anthracene & 13.465 & 10.295 & 7.953 & 6.145 \\ Benzo[g,h,i]Perilene & 5.670 & 1.538 & 4.695 & 1.538 \\ Crysene & 6.228 & 4.193 & 9.175 & 4.065 \\ Phenanthrene & 103.723 & 77.238 & 72.873 & 51.878 \\ Fluoranthene & 14.000 & 8.473 & 15.990 & 10.693 \\ Fluorene & 84.898 & 78.830 & 88.820 & 47.730 \\ Naphthalene & 164.510 & 67.385 & 103.665 & 68.620 \\ Pyrene & 11.433 & 7.058 & 15.128 & 7.745 \\
**Total PAHs** & **511.498** & **390.853** & **582.118** & **247.690** \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Mean annual PAH levels (ng m\({}^{-2}\)d\({}^{-1}\)) determined in the four investigated locations. Figure 4: Concentrations (expressed as ng m\({}^{-2}\)d\({}^{-1}\)) of each PAH in the deposition rates in the four locations for each season. For the acronyms: BaA Benzo[a]Anthracene; BJF Benzo[b]Fluoranthene; BJF Benzo[j]Fluoranthene; BJF Benzo[k]Fluoranthene; BaP Benzo[a]Pyrene; DHA Dibenzo[a,h]Anthracene; DeP Dibenzo[a,e]Pyrene; DhP Dibenzo[a,h]Pyrene; DiP Dibenzo[a,h]Pyrene; DIP Dibenzo[a,l]Pyrene; ICP Indeno[1,2,3-cd]Pyrene; ACE Acenaphthene; ACY Acenaphthylene; ANT Anthracene; BhP Benzo[g,h,i]Perylene; CRY Chrisene; Phen Phenanthrene; FLT Fluoranthene; FLU Fluorene; NaP Naphthalene; PyR Pyrene. As already observed in the previous study [67], the highest contribution is due to the lighter PAHs.