## 3 Results and Discussion
### Source Apportionment Model  
Two well-known source apportionment models (CMB and positive matrix factorization (PMF)) have been used for several decades to identify the complex sources of carbonaceous aerosols. CMB is based on an effective variance least squares (EVLS) multilinear regression method. PMF is an explicit point-by-point weighted least squares factor analysis method imposed with non-negativity constraints. Although CMB does not require a minimum set of input data, the selection of the source profile controls the model result sensitivities. The results obtained from the CMB model using the source profiles obtained in this study are presented in Table 5 and Figure 5. The data, employed for the analysis conducted in the CMB model, were comprised of a total of 160 compounds including PM\({}_{2.5}\), OC, EC, PAHs and hopanes and steranes, etc.; the analysis of organic molecular markers of the biomass burning used the results of study presented in 'Section 3.1'. As illustrated in the figure, the origins of PM\({}_{2.5}\) in the subject area of the present study appeared as in the following order: secondarily created ionic substances (54.10%) > contribution to the secondary created particulate matters and long-distance pollutants (20.02%) > biomass burning from agricultural crop residues (8.96%) and forest tree types (1.56%) (10.53%) > emission from vehicles of gasoline engine (4.79%) > Burning of meats or others in restaurants (2.65%). With regard to the comparison of residential area with the area on roads, the secondarily created ionic substances and the secondarily created particulate matters and long-distance pollutants, which occupy most origins of PM\({}_{2.5}\), appeared with similar rates over 72% commonly in residential area and on roads. For the case of the biomass burning, it appeared higher in the residential area (14.4%) than on roads (8.2%) due to relatively higher impacts from the open-burning of agricultural crop residues; the emission from vehicles of gasoline engine and from the burning in restaurants appeared higher on roads than those in the residential area. The rest of the burning of natural gas, combustion in coal burning thermal power plants, and water soluble ionic substances (sea-salt particulates), etc. were commonly identified as exhibiting no significant differences between residential area and on roads. In this study, there are still limitation about secondary mass from primary in the CMB result as shown in Table 5. The identified sources of secondary ions, SOA and oxidized trace elements may include mass from the primary sources such as biomass burning and car emission.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \multicolumn{2}{c}{**Overall Avg**} & \multicolumn{2}{c}{**Residential Area**} & \multicolumn{2}{c}{**Roadside Area**} \\ \cline{2-7}  & \(\mu\)g/m\({}^{3}\) & \% & \(\mu\)g/m\({}^{3}\) & \% & \(\mu\)g/m\({}^{3}\) & \% \\ \hline PM\({}_{2.5}\) mass & 27.54 & 100.00 & 20.769 & 100.00 & 34.306 & 100.00 \\ \hline Biomass burning (agricultural crop residues) & 2.47 & 8.96 & 2.52 & 12.13 & 2.42 & 7.05 \\ Biomass burning (forest tree types) & 0.43 & 1.56 & 0.47 & 2.24 & 0..40 & 1.15 \\ Vegetative detritus & 0.79 & 2.87 & 0.664 & 3.20 & 0.916 & 2.67 \\ Natural gas combustion & 0.14 & 0.49 & 0.111 & 0.54 & 0.160 & 0.46 \\ Diesel car emission & 0.52 & 1.87 & 0.422 & 2.03 & 0.609 & 1.77 \\ Gasoline car emission & 1.32 & 4.79 & 0.726 & 3.49 & 1.914 & 5.58 \\ Meat cooking emission & 0.73 & 2.65 & 0.244 & 1.18 & 1.217 & 3.55 \\ Coal combustion & 0.40 & 1.44 & 0.325 & 1.57 & 0.469 & 1.37 \\ Secondary ions & 14.90 & 54.10 & 10.856 & 52.27 & 18.938 & 55.20 \\ Water soluble salts & 0.36 & 1.32 & 0.286 & 1.38 & 0.441 & 1.28 \\ SOA, oxidized trace elements, and/or long range transfer & 5.51 & 20.02 & 4.149 & 19.98 & 6.877 & 20.05 \\ \hline \hline \end{tabular}
\end{table}
Table 5: Source apportionment results of PM\({}_{2.5}\).