## 3 Results and Discussion  
Figure 4 shows the size-resolved MEE for each different source based on the results of Equation (6). A d\({}_{\rm g}\) of 0.1-2.5 \(\upmu\)m and GSDs of 1.5, 2.1, and 2.5 were considered. For a GSD of 1.5, maximum MEEs were 4.471 m\({}^{2}\) g\({}^{-1}\) for TS (d\({}_{\rm g}\) of 0.3 \(\upmu\)m), 3.802 m\({}^{2}\) g\({}^{-1}\) for LS (d\({}_{\rm g}\) of 0.4 \(\upmu\)m), 5.064 m\({}^{2}\) g\({}^{-1}\) for LN (d\({}_{\rm g}\) of 0.3 \(\upmu\)m), 3.418 m\({}^{2}\) g\({}^{-1}\) for G (d\({}_{\rm g}\) of 0.3 \(\upmu\)m), 11.004 m\({}^{2}\) g\({}^{-1}\) for D (d\({}_{\rm g}\) of 0.2 \(\upmu\)m), 10.229 m\({}^{2}\) g\({}^{-1}\) for TBB (d\({}_{\rm g}\) of 0.3 \(\upmu\)m), 6.335 m\({}^{2}\) g\({}^{-1}\) for LBB (d\({}_{\rm g}\) of 0.3 \(\upmu\)m), and 1.655 m\({}^{2}\) g\({}^{-1}\) for FSD (d\({}_{\rm g}\) of 0.3 \(\upmu\)m). As the properties (MEE, MAE, and MSE) are size-dependent for each chemical compound and source, there are many ranges depending on GSD and d\({}_{\rm g}\). Table 2 shows the ranges of MEE, MAE, and MSE for each source for GDS of 1.5-2.5 and d\({}_{\rm g}\) of 0.1-2.5 \(\upmu\)m. The values extended over a wide range. Taking TS as an example, the maximum MEE, MAE, and MSE ranged from 0.098 to 4.471, 0.000 to 0.112, and 0.061 to 4.471 m\({}^{2}\) g\({}^{-1}\), respectively. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Source** & **Range** & **MEE** & **MAE** & **MSE** \\ \hline TS & min & 0.098 & 0.000 & 0.061 \\  & max & 4.471 & 0.112 & 4.471 \\  & min & 0.089 & 0.036 & 0.053 \\  & max & 3.802 & 0.397 & 3.409 \\  & min & 0.110 & 0.047 & 0.063 \\  & max & 5.064 & 0.345 & 4.792 \\  & min & 0.062 & 0.034 & 0.028 \\  & max & 3.418 & 0.750 & 2.693 \\  & min & 0.185 & 0.099 & 0.086 \\  & max & 11.004 & 4.604 & 6.438 \\  & min & 0.191 & 0.084 & 0.107 \\As shown in Figure 4, the MEEs peaked at a d\({}_{\rm g}\) of \(\sim\)0.3 \(\upmu\)m for a GSD of 1.5 for all sources and showed a declining trend as d\({}_{\rm g}\) increased. The d\({}_{\rm g}\) at which MEEs had peak values decreased as GSD increased. However, detailed MEE values differed depending on the sources. Figure 4 shows that D and TBB sources had relatively higher MEE values compared with the other sources. They had  
Figure 4: Source-based mass extinction efficiency as a function of the geometric mean diameter for different geometric standard deviations for (**a**) transported secondary sources (TS), (**b**) local secondary sulfates (LS), (**c**) local secondary nitrates (LN), (**d**) gasoline (G), (**e**) diesel (D), (**f**) transported biomass burning (TBB), (**g**) local biomass burning (LBB), and (**h**) fugitive soil dust (FSD). maximum values higher than 10 m\({}^{2}\) g\({}^{-1}\) in submicron sizes for a GSD value of 1.5. Meanwhile, the FSD and the G sources were characterized by relatively lower MEEs with maximum values of less than 2 and 3 m\({}^{2}\) g\({}^{-1}\), respectively, for a GSD of 1.5. Thus, assuming size-dependent MEEs as constant variables may result in significant errors in estimating aerosol optical properties. Another important parameter in estimating aerosol optical properties is the aerosol light-absorbing property. This light absorption property is mainly determined by EC. As shown in Table 1, the imaginary refractive index was 0.44, which means that EC was the main light-absorbing compound. In this study, we assumed OM to be a non-absorbing compound. However, some OM (e.g., HULIS) is known to have weakly to moderate light-absorbing ability depending on its characteristics [8; 9]. In order to identify the effects of the source-resolved MEEs on HULIS light-absorbing property, HULIS imaginary refractive index was tested. Figure 5 compares the size-resolved MEE for each source with the various HULIS imaginary refractive indices. The HULIS imaginary refractive indices of 0.006 and 0.1 with a GSD value of 1.5 were compared. As shown in Figure 5, the TS, LS, and FSD sources had an insignificant impact on the variation of HULIS imaginary refractive index.