## 3 Results and Discussion
### Ambient Concentrations
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Compounds**} & \multirow{2}{*}{**Unit**} & \multicolumn{6}{c}{**Site 1 (Residential Area)**} & \multicolumn{6}{c}{**Site 2 (Roadside Area)**} \\ \cline{2-10}  & & \multicolumn{2}{c}{**Spring**} & **Summer** & **Fall** & **Winter** & **Spring** & **Summer** & **Fall** & **Winter** \\ \hline PM\({}_{2.5}\) & ug/m\({}^{3}\) & 16.47 \(\pm\) 0.75 & 22.71 \(\pm\) 0.47 & 18.59 \(\pm\) 1.79 & 18.50 \(\pm\) 1.80 & 29.27 \(\pm\) 3.83 & 231.7 \(\pm\) 1.01 & 12.02 \(\pm\) 1.26 & 62.79 \(\pm\) 0.96 \\ OC & ug/m\({}^{3}\) & 4.81 & 6.22 & 6.30 & 2.65 & 5.42 & 3.58 & 11.46 \\ EC & ug/m\({}^{3}\) & 0.76 & 1.94 & 1.32 & 0.38 & 2.36 & 1.78 & 1.99 & 1.50 \\ K\({}^{+}\) & ug/m\({}^{3}\) & 0.07 & 0.09 & 0.20 & 0.17 & 0.19 & 0.09 & 0.10 & 0.47 \\ SO\({}^{2-}\) & ug/m\({}^{3}\) & 3.23 & 10.11 & 3.14 & 5.08 & 5.42 & 10.74 & 2.62 & 11.81 \\ NO\({}_{3}\)\({}^{-}\) & ug/m\({}^{3}\) & 4.30 & 0.11 & 2.99 & 3.96 & 2.53 & 0.08 & 0.67 & 24.69 \\ NH\({}_{4}\)\({}^{+}\) & ug/m\({}^{3}\) & 2.10 & 3.51 & 1.99 & 2.92 & 2.59 & 3.54 & 1.05 & 10.02 \\ Cl\({}^{+}\) & ug/m\({}^{3}\) & 0.04 & 0.00 & 0.03 & 0.45 & 0.03 & 0.00 & 0.01 & 1.11 \\ Na\({}^{+}\) & ug/m\({}^{3}\) & 0.06 & 0.04 & 0.06 & 0.26 & 0.08 & 0.05 & 0.14 & 0.17 \\ Mg\({}^{2+}\) & ug/m\({}^{3}\) & 0.01 & 0.01 & 0.02 & 0.05 & 0.03 & 0.02 & 0.03 & 0.08 \\ Ca\({}^{2+}\) & ug/m\({}^{3}\) & 0.05 & 0.01 & 0.03 & 0.03 & 0.12 & 0.03 & 0.05 & 0.13 \\ levoglucans & ng/m\({}^{3}\) & 239 & 197 & 1173 & 722 & 985 & 76 & 134 & 2834 \\ Cholesterol & ng/m\({}^{3}\) & 0.00 & 0.79 & 0.00 & 0.00 & 4.24 & 0.00 & 0.00 & 11.19 \\ \(\Sigma\)PAHs & ng/m\({}^{3}\) & 8.31 & 5.32 & 27.97 & 43.22 & 45.40 & 5.33 & 7.71 & 170.72 \\ \(\Sigma\)Hopanes \(\Sigma\) and Sterane & ng/m\({}^{3}\) & 0.45 & 0.26 & 0.92 & 1.00 & 4.00 & 0.80 & 0.76 & 6.14 \\ \(\Sigma\)Alkanes & ng/m\({}^{3}\) & 81 & 69 & 241 & 147 & 456 & 66 & 65 & 841 \\ \(\Sigma\)Cyclo-alkanes & ng/m\({}^{3}\) & ND \({}^{1}\)) & ND & ND & ND & ND & ND & 3.79 \\ \(\Sigma\)Alkano acids & ng/m\({}^{3}\) & 321 & 223 & 644 & 365 & 1261 & 244 & 256 & 2149 \\ \(\Sigma\)benzene carboxylic acids & ng/m\({}^{3}\) & 103 & 142 & 223 & 243 & 435 & 88 & 80 & 812 \\ \(\Sigma\)Alkanoic Dacids & ng/m\({}^{3}\) & 276 & 188 & 200 & 201 & 633 & 105 & 120 & 699 \\ \(\Sigma\)Other acids & ng/m\({}^{3}\) & 599 & 1930 & 976 & 212 & 4281 & 1568 & 315 & 1497 \\ \hline \hline \end{tabular} \({}^{1}\) Not detected  
\end{table} 
Table 4: Ambient concentrations of major chemical components of PM\({}_{2.5}\) measured at the residential area and roadside area. The compounds, analyzed as an organic indicator of WIOC, were 56 compounds of PAHs and alkanes; the percentage of PAHs and alkanes to weight of PM\({}_{2.5}\) were 0.15% and 0.97%, respectively. PAHs are emitted through incomplete combustion of fossil fuels and biomass. In the present study, the annual average concentration of PAHs in residential area appeared as approximately 84.82 ng/m\({}^{3}\), while it appeared on roads as 229.16 ng/m\({}^{3}\) showing higher level of annual average concentration than that appeared in the residential area. This was estimated that it would be attributable to PAHs created from the combustion of fuels of motor vehicles that affected the area of roads. The detected seasonal concentration of PAHs commonly marked the highest level in both residential area and on roads in wintertime (residential area 43.22 ng/m\({}^{3}\), roads 170.72 ng/m\({}^{3}\)), whereas it marked the lowest level in summertime (residential area 5.32 ng/m\({}^{3}\), roads 5.33 ng/m\({}^{3}\)). According to previously conducted studies, the higher concentration of PAHs in wintertime was reported to be associated with the effect of phenomenon of cold ignition of vehicles; while the lower concentration of PAHs has been reported that it would be attributable to the effect of photochemical decomposition [51; 52].