## 3 Results and Discussion
### Aerosol Concentration Distributions

Table 2: Statistical summary for the results of aerosol mass concentration by particle size (\(D\), \(\mu\)m) for the instances of meteorological phenomena; all variables are expressed in \(\mu\)g\(\cdot\)m\({}^{-3}\). To examine the aerosol concentration characteristics for each phenomenon, the concentration distributions for each of the five phenomena are shown in Figure 6a. Overall, the distribution showed a bimodal shape with two peaks in the 1 st and 4 th channels. For PR, the average concentration decreased by 31.6 % compared to CD across all particle size channels, most notably in the 5-10 \(\upmu\)m channel, where a 66.2% difference was observed. Thus, it displayed the influence of the washout effect of precipitation through the substantially reduced number of coarse particles. Furthermore, the proportion of mass concentration for each phenomenon by particle size was compared with that for CD. The average concentration for AD increased more than six times in the coarse mode and 2.5 times in the 0.5-1 \(\upmu\)m channel. During HZ events, the concentrations increased by 1.16-3.48 times across all particle size distributions, whereas for MI events, the concentrations decreased by factors of 0.7 in the 3-5 \(\upmu\)m channel but increased by 2.67 times in the 0.3-0.5 \(\upmu\)m channel (Figure 6b). Figure 7 shows the distribution of meteorological variables by phenomena. According to the meteorological observation guidelines of KMA [11], the haze and mist were classified based on an RH of 70-80% when a visibility disturbance occurs. During MI events, the average daily humidity was 70.2%, which was relatively high compared to those of AD (41.2%), HZ (44.8%), and CD (47.5%). This pattern may be likely attributed to the increase in number concentration by coagulation and subsequent growth when fine particles \(\leq\) 1 \(\upmu\)m are hygroscopic. Moreover, instances of MI and PR related to atmospheric hygrometers \begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline  & & \multicolumn{8}{c}{**Logarithmic Transformation**} \\ \cline{3-11}
**Variables** & **Cases** & **0.3–0.5** & **0.5–1.0** & **1.0–3.0** & **3.0–5.0** & **5.0–10** & **0.3–0.5** & **0.5–1.0** & **1.0–3.0** & **3.0–5.0** & **5.0–10** \\ \hline \multirow{4}{*}{Skewness} & AD & 0.51 & 3.97 & 4.79 & 4.70 & 4.63 & \(-\)0.63 & 1.43 & 1.84 & 1.63 & \(-\)0.09 \\  & HZ & 0.62 & 0.26 & 0.68 & 2.16 & 2.00 & \(-\)0.52 & \(-\)0.25 & 0.06 & 0.18 & \(-\)0.08 \\ \cline{1-1}  & MI & 0.28 & 1.73 & 1.51 & 4.62 & 2.30 & \(-\)0.74 & \(-\)0.66 & \(-\)0.76 & \(-\)0.64 & \(-\)0.49 \\ \cline{1-1}  & PR & 1.44 & 1.90 & 4.26 & 6.18 & 7.74 & \(-\)0.36 & \(-\)1.28 & \(-\)0.52 & \(-\)0.46 & 0.27 \\ \cline{1-1}  & CD & 1.17 & 2.03 & 1.84 & 0.94 & 1.78 & \(-\)0.09 & 0.57 & \(-\)0.42 & \(-\)1.58 & \(-\)1.17 \\ \hline \multirow{4}{*}{Kurtosis} & AD & \(-\)0.22 & 16.78 & 23.26 & 22.39 & 21.84 & \(-\)0.66 & 1.38 & 3.59 & 3.43 & \(-\)0.76 \\ \cline{1-1}  & HZ & \(-\)0.66 & \(-\)1.23 & \(-\)0.80 & 4.87 & 4.36 & \(-\)0.38 & \(-\)1.49 & \(-\)1.21 & \(-\)0.46 & \(-\)0.90 \\ \cline{1-1}  & MI & \(-\)0.77 & 2.69 & 3.74 & 24.91 & 5.90 & \(-\)0.52 & 2.22 & 0.48 & 1.84 & \(-\)0.02 \\ \cline{1-1}  & PR & 1.47 & 8.00 & 26.57 & 47.76 & 68.41 & 0.01 & 6.86 & 0.43 & 1.08 & \(-\)0.09 \\ \cline{1-1}  & CD & 1.02 & 4.35 & 3.31 & 0.68 & 3.81 & \(-\)0.86 & \(-\)0.08 & 0.95 & 3.23 & 2.27 \\ \hline \hline \end{tabular} AD: Asian dust, HZ: haze, MI: mist, PR: precipitation, and CD: clear days.  
\end{table} 
Table 3: Skewness and Kurtosis for the aerosol mass concentration by particle size before and after logarithmic transformation for the instances of meteorological phenomena. Figure 6: **(a) Aerosol mass concentration size distribution for the AD, HZ, MI, PR, and CD cases. (b) The proportion of mass concentration for each phenomenon (AD, HZ, MI, and PR) by particle size compared with CD conditions (dashed line). **  
were associated with high RH, whereas wind speeds \(\leq\) 2.5 m\(\cdot\)s\({}^{-1}\) were observed in all cases, except for AD.