## 3 Results and Discussion
### \(\delta^{13}\)C of Habitat Plants and LV-WSOC in PM from Noyaki  
The results of plant carbon analysis showed \(\delta^{13}\)C values of \(-\)11.97 \(\pm\) 0.13% and \(-\)30.25 \(\pm\) 0.05% for _Miscanthus sinensis_ and _Pleibolastus chino_ var. _viridis_, respectively. This provided evidence supporting that those plants were C4 and C3 plants, respectively. The results of particulate LV-WSOC analysis showed variation from \(-\)13.8 to \(-\)21.7%, mostly above \(-\)20% (Table 3). It should be noted that even though \(\delta^{13}\)C values for the background air indicated heavier isotopic compositions compared to the noyaki samples, those values were unreliable since total carbon loaded on the filters was very low and the impact of the blank value was significant. An improved sampling method was needed for the determination of \(\delta^{13}\)C with background LV-WSOC. For the noyaki samples, the average \begin{table}
\begin{tabular}{l c c c c c} \hline \hline \multicolumn{1}{c}{**Sample**} & \multicolumn{2}{c}{**Nitrogen**} & \multicolumn{2}{c}{**Carbon**} \\ \hline  & **Mass \({}^{\star}\)** & **Conc. \({}^{\star}\)** & **Mass \({}^{\star}\)** & **Conc. \({}^{\star}\)** & \(\delta^{13}\)C\({}_{\textbf{VPDO}}\)\({}^{\star}\)** \\ \hline  & \(\mu\)gN & \(\mu\)gN & \(\mu\)gC & \(\mu\)gC & \\  & filter\({}^{-1}\) & m\({}^{-3}\) & filter\({}^{-1}\) & m\({}^{-3}\) & \% \\ \hline \multicolumn{5}{l}{_Noyaki samples_} \\ \hline
24 March 2019, Daikanpo 1 st BAuT filter 1 & LDL \({}^{\dagger}\) & LDL \({}^{\ddagger}\) & 102 & 37 & \(-\)14.43 \\ \hline
24 March 2019, Daikanpo 1 st BAuT filter 2 & 2 & 0.6 & 128 & 36 & \(-\)18.36 \\ \hline
24 March 2019, Daikanpo 1 st BAuT filter 3 & 5 & 1.3 & 584 & 140 & \(-\)18.96 \\ \hline
24 March 2019, Daikanpo 2 nd BAuT filter 2 & LDL \({}^{\ddagger}\) & LDL \({}^{\dagger}\) & 85 & 28 & \(-\)20.89 \\ \hline
24 March 2019, Daikanpo filter 1 & 3 & 2.5 & 71 & 53 & \(-\)13.81 \\ \hline
24 March 2019, Daikanpo filter 2 & 0 & 0.2 & 68 & 40 & \(-\)17.39 \\ \hline
24 March 2019, Daikanpo filter 3 & 23 & 11.6 & 396 & 203 & \(-\)19.03 \\ \hline
24 March 2019, Daikanpo filter 4 & 1 & 1.0 & 69 & 47 & \(-\)20.38 \\ \hline
6 April 2019, Namino BAuT filter & 56 & 16.0 & 472 & 135 & \(-\)19.36 \\ \hline
6 April 2019, Namino noyaki filter & 36 & 21.1 & 323 & 191 & \(-\)19.11 \\ \hline
14 March 2021, Komezuka BAuT filter & 2 & 0.2 & 127 & 11 & \(-\)14.10 \\ \hline
23 March 2021, Ubuyama BAuT filter & 84 & 8.7 & 1018 & 106 & \(-\)21.65 \\ \hline
27 March 2021, Kitayama BAuT filter 1 & LDL \({}^{\ddagger}\) & LDL \({}^{\ddagger}\) & 202 & 38 & \(-\)17.56 \\ \hline
27 March 2021, Kitayama BAuT filter 2 & 4 & 1.8 & 517 & 243 & \(-\)18.94 \\ \hline
27 March 2021, Kitayama BAuT filter 3 & LDL \({}^{\ddagger}\) & LDL \({}^{\ddagger}\) & 107 & 39 & \(-\)16.26 \\ \hline \multicolumn{5}{l}{_Background air samples_} \\ \hline
31 March 2019, Namino background & 3 & 0.5 & 7 & 1 & 1.90 \\ \hline
23 May 2019, Namino background & NA \({}^{\ddagger}\) & NA \({}^{\ddagger}\) & NA\({}^{\ddagger}\) & Na \({}^{\ddagger}\) \\ \hline
23 April 2021, Ubuyama background & 9 & 0.5 & 18 & 1 & \(-\)9.34 \\ \hline
10 May 2021, Kitayama background & 49 & 1.7 & 32 & 1 & \(-\)13.90 \\ \hline
25 May 2021, Kitayama background & 11 & 0.4 & 25 & 1 & \(-\)13.04 \\ \hline
1 June 2021, Namino background & 7 & 0.3 & 2 & 0.1 & 14.31 \\ \hline \multicolumn{5}{l}{\({}^{\star}\) Values were blank-corrected. \({}^{\ddagger}\) Lower than detection limit. \({}^{\ddagger}\) Analysis failed and data are not available.} \\ \end{tabular}
\end{table} 
Table 3: Nitrogen mass, carbon mass, and \(\delta^{13}\)C of low-volatile water-soluble organic component in PM emitted from Noyaki. \(\delta^{13}\)C value was \(-18\pm 2\%\). Using the plant \(\delta^{13}\)C values referred to earlier in a mass balance, the contribution of LV-WSOC from _Miscanthus sinensis_ and _Pleioblastus chino_ var. _viridis_ was estimated to be 67 and 33%, respectively, implying the fractions of the habitats of those plants in this region.