# Seasonal Characteristics of Particulate Matter by Pollution Source Type and Urban Forest Type
## 3 Results
### Analysis of \(PM_{10}\) Concentrations in Each Plot
#### 3.2.2 Comparison of PM Concentration Distribution  
Table 3 presents the probability of PM\({}_{10}\) concentrations reaching levels classified as \"bad\" or above (above 81 ug/m\({}^{3}\)). For Gomae, the lowest probability of \"bad\" PM\({}_{10}\) levels were found at forest interior 1, while Yangjae and Gwanak exhibited the lowest probabilities at forest interior 2. Among these sites, the forest interior at Gomae, which is composed solely of trees, showed the most significant difference in the likelihood of \"bad\" \(PM_{10}\) concentrations compared to surrounding areas. Similarly, the forest interiors in Yangjae, which is a park, and in Gwanak, located within a university campus, also demonstrated lower probabilities of high PM\({}_{10}\) levels than the pollution sources. For the industrial complexes, excluding Gjiang, which had generally low PM\({}_{10}\) concentrations, Goyang and Sihwa industrial areas showed a higher probability of PM\({}_{10}\) levels exceeding the \"bad\" threshold compared to the road areas. However, urban forests and residential areas showed a gradual decrease in PM\({}_{10}\) concentrations compared to the pollution sources. In addition, Figure 5 illustrates the overall distribution of PM\({}_{10}\) concentrations throughout the year (0-200 ug/m\({}^{3}\)) as well as the distribution of concentrations in the 0-80 ug/m\({}^{3}\) range, which represents typical conditions and constitutes a substantial portion of the data set. The overall distribution of data across the entire study period (Figure 5) indicates a right-skewed pattern, with many values clustering within the 0-100 ug/m\({}^{3}\) range, with no significant differences observed across regions or plots. However, when examining the data by subdivided periods, distinct differences between plots emerged. \begin{table}
\begin{tabular}{c c c c c c c c} \hline  & \multicolumn{3}{c}{**Non-Point Pollution**} & \multicolumn{5}{c}{**Point Pollution**} \\ \cline{2-9}  & **Road** & **Interior1** & **Interior2** & \multicolumn{2}{c}{**Industrial Area**} & **Forest** & **Residential Area** \\ \hline GM & 0.0686 & 0.0544 & 0.0830 & GJ & 0.0159 & 0.0154 & 0.0083 \\ YJ & 0.0822 & 0.0821 & 0.0784 & GY & 0.1050 & 0.0918 & 0.0399 \\ GW & 0.0894 & 0.0845 & 0.0790 & SH & 0.1056 & 0.0969 & 0.0932 \\ \hline \end{tabular}
\end{table} 
Table 3: Probability of PM\({}_{10}\) concentrations reaching levels classified as “Bad” or above (above 81 ug/m\({}^{3}\)). \begin{table}
\begin{tabular}{c c c c c c c c} \hline  & \multicolumn{2}{c}{**Early Winter**} & \multicolumn{2}{c}{**Early Spring**} & \multicolumn{2}{c}{**Springer (M \(\pm\) SD)**} & \multicolumn{2}{c}{**Summer**} & \multicolumn{2}{c}{**Autumn**} & **Late Winter** \\ \hline \multirow{8}{*}{Non-point pollution} & Forest & & & & & & & \\  & interior1 & & & & & & & \\ \cline{2-9}  & Forest interior2 & & & & & & & \\ \cline{2-9}  & Road & 51.07 \(\pm\) 26.90 & 54.96 \(\pm\) 38.28 & 42.71 \(\pm\) 39.93 & 20.13 \(\pm\) 12.36 & 37.61 \(\pm\) 21.99 & 40.54 \(\pm\) 20.37 \\ \cline{2-9}  & Downtown & 43.47 \(\pm\) 26.32 & 56.37 \(\pm\) 57.44 & 57.09 \(\pm\) 93.66 & 23.67 \(\pm\) 14.92 & 37.97 \(\pm\) 28.85 & 41.07 \(\pm\) 24.01 \\ \cline{2-9}  & \(\chi^{2}\) & 316.37 * & 27.59 * & 50.76 * & 998.79 * & 105.33 * & 62.18 * \\ \hline \multirow{8}{*}{Point pollution} & Forest & 46.17 \(\pm\) 29.16 & 49.90 \(\pm\) 39.33 & 39.68 \(\pm\) 43.25 & 17.51 \(\pm\) 11.68 & 31.36 \(\pm\) 24.05 & 34.04 \(\pm\) 22.50 \\ \cline{2-9}  & Residency & 37.68 \(\pm\) 25.84 & 38.76 \(\pm\) 34.28 & 33.55 \(\pm\) 34.37 & 16.12 \(\pm\) 11.92 & 31.11 \(\pm\) 26.24 & 34.21 \(\pm\) 23.84 \\ \cline{2-9}  & Industrial area & & & & & & \\ \cline{2-9}  & Downtown & 41.07 \(\pm\) 26.98 & 55.47 \(\pm\) 70.68 & 50.60 \(\pm\) 78.88 & 24.00 \(\pm\) 14.09 & 34.39 \(\pm\) 26.49 & 34.27 \(\pm\) 22.41 \\ \cline{2-9}  & \(\chi^{2}\) & 356.15 * & 399.62 * & 270.79 * & 2378.16 * & 70.46 * & 8.83 * \\ \hline \end{tabular}
\end{table} 
Table 2: The Kruskal–Wallis test results of road site \(PM_{10}\) concentrations (ug/m\({}^{3}\)) in each season.