## 3 Results
### Changes in PM According to Mist Spraying at YCF  
The concentrations of PM\({}_{10}\), PM\({}_{2.5}\), and PM\({}_{1.0}\) at the measuring points increased twice to thrice as soon as mist spraying began (Figure 3a). However, as the spraying ended, the PM concentration immediately decreased and returned to its initial value. The concentra  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{3}{*}{**Measuring Time**} & \multirow{3}{*}{**Mist Spray**} & \multicolumn{3}{c}{**Yangjae Citizen’s Forest**} & \multicolumn{3}{c}{**Cheongdam Road Park**} \\ \cline{3-8}  & & \multirow{2}{*}{**Temperature**} & **Relative** & **Wind** & \multirow{2}{*}{**Temperature**} & **Relative** & **Wind** \\  & & & & **Humidity** & **Speed** & & **Humidity** & **Speed** \\ \cline{3-8}  & & \multicolumn{1}{c}{\(\cdots\)C} & \multicolumn{1}{c}{\(\cdots\)\(\cdots\)} & \multicolumn{1}{c}{\(\cdots\)\(\cdots\)} & \multicolumn{1}{c}{\(\cdots\)C} & \multicolumn{1}{c}{\(\cdots\)\(\cdots\)} & \multicolumn{1}{c}{\(\cdots\)\(\cdots\)} & \multicolumn{1}{c}{\(\cdots\)\(\cdots\)} \\ \hline \multirow{3}{*}{Evening Rush hour} & Before & 25.4 \({}^{\text{a}}\) & 26.8 \({}^{\text{a}}\) & 0.4 \({}^{\text{a}}\) & 24.4 \({}^{\text{a}}\) & 24.2 \({}^{\text{a}}\) & 0.5 \({}^{\text{a}}\) \\  & & (\(\pm\)0.2) & (\(\pm\)0.7) & (\(\pm\)0.0) & (\(\pm\)0.2) & (\(\pm\)0.9) & (\(\pm\)0.1) \\  & & 25.2 \({}^{\text{a}}\) & 27.9 \({}^{\text{a}}\) & 0.4 \({}^{\text{a}}\) & 24.2 \({}^{\text{a}}\) & 25.0 \({}^{\text{a}}\) & 0.5 \({}^{\text{a}}\) \\  & & (\(\pm\)0.3) & (\(\pm\)1.3) & (\(\pm\)0.0) & (\(\pm\)0.3) & (\(\pm\)1.3) & (\(\pm\)0.1) \\  & & 25.0 \({}^{\text{a}}\) & 27.4 \({}^{\text{a}}\) & 0.4 \({}^{\text{a}}\) & 24.1 \({}^{\text{a}}\) & 24.8 \({}^{\text{a}}\) & 0.4 \({}^{\text{a}}\) \\  & & (\(\pm\)0.3) & (\(\pm\)1.5) & (\(\pm\)0.0) & (\(\pm\)0.2) & (\(\pm\)1.3) & (\(\pm\)0.1) \\ \hline \multirow{3}{*}{Morning Rush hour} & Before & & & & 24.6 \({}^{\text{a}}\) & 18.4 \({}^{\text{a}}\) & 1.2 \({}^{\text{a}}\) \\  & & & & (\(\pm\)0.2) & (\(\pm\)0.3) & (\(\pm\)0.1) \\  & & & & & 24.6 \({}^{\text{a}}\) & 18.9 \({}^{\text{a}}\) & 1.3 \({}^{\text{a}}\) \\  & & & & & (\(\pm\)0.2) & (\(\pm\)0.4) & (\(\pm\)0.1) \\  & & & & & 24.7 \({}^{\text{a}}\) & 18.2 \({}^{\text{a}}\) & 1.2 \({}^{\text{a}}\) \\  & & & & & (\(\pm\)0.4) & (\(\pm\)0.4) & (\(\pm\)0.1) \\ \hline \multirow{3}{*}{Lunch} & Before & 23.3 \({}^{\text{a}}\) & 22.3 \({}^{\text{a}}\) & 1.4 \({}^{\text{a}}\) & 20.4 \({}^{\text{a}}\) & 14.4 \({}^{\text{a}}\) & 0.9 \({}^{\text{a}}\) \\  & & (\(\pm\)0.1) & (\(\pm\)0.2) & (\(\pm\)0.1) & (\(\pm\)0.3) & (\(\pm\)0.2) & (\(\pm\)0.1) \\ \cline{1-1}  & & 23.2 \({}^{\text{a}}\) & 22.9 \({}^{\text{a}}\) & 1.3 \({}^{\text{a}}\) & 20.4 \({}^{\text{a}}\) & 14.8 \({}^{\text{a}}\) & 1.1 \({}^{\text{a}}\) \\ \cline{1-1}  & & (\(\pm\)0.1) & (\(\pm\)0.4) & (\(\pm\)0.2) & (\(\pm\)0.3) & (\(\pm\)0.4) & (\(\pm\)0.1) \\ \cline{1-1}  & & 23.5 \({}^{\text{a}}\) & 22.6 \({}^{\text{a}}\) & 1.0 \({}^{\text{a}}\) & 20.8 \({}^{\text{a}}\) & 14.5 \({}^{\text{a}}\)tion variation of PM\({}_{10}\) was lower than that of PM\({}_{2.5}\) and PM\({}_{1.0}\) in the evening rush hour, whereas the concentration variation of PM\({}_{10}\) was large during lunch. However, after the end of spraying, the PM ratio was the same as before (Figure 3b). During the evening rush hour, PM\({}_{2.5}\):PM\({}_{10}\)\({}^{-1}\) and PM\({}_{1.0}\):PM\({}_{10}\)\({}^{-1}\) increased, and PM\({}_{1.0}\):PM\({}_{2.5}\)\({}^{-1}\) decreased as mist was sprayed. In contrast, during lunch, PM\({}_{2.5}\):PM\({}_{10}\)\({}^{-1}\), PM\({}_{1.0}\):PM\({}_{10}\)\({}^{-1}\), and PM\({}_{1.0}\):PM\({}_{2.5}\)\({}^{-1}\) were reduced. When spraying mist, PM\({}_{10}\), PM\({}_{2.5}\), and PM\({}_{1.0}\) concentrations were 3.6-, 2.6-, and 2.6-fold higher than the respective concentrations before spraying, respectively, and returned to the previous concentration after spraying (Table 2). The change in PM\({}_{10}\) concentration was lower than that in PM\({}_{2.5}\) and PM\({}_{1.0}\) during the evening rush hour.