## 3 Results and Discussion
### OC and EC Fractions
#### 3.3.1. Effect of PMs Accumulation by Transportation and Local Emission in PE1 and PE2  
The growth rates of OC in PE1 were comparable for PM\({}_{1}\) and PM\({}_{1-2.5}\), with values of 5.18 and 2.84 ug\(\cdot\)m\({}^{-3}\cdot\)day\({}^{-1}\), respectively (Table 3), which come up to 21% and 16% of the mass growth rates of PM\({}_{1}\) and PM\({}_{1-2.5}\). The values increased up to 27% and 23% if we calculated TC growth rate to PM\({}_{1}\) and PM\({}_{1-2.5}\) mass. Interestingly, the percentages of TC in PM\({}_{1}\) and PM\({}_{1-2.5}\) mass were 30% and 24%, respectively, on the day of peak concentration. Additionally, the three sizes of PM mass concentration had similar increase rates. All this does not seem to take place chemical reaction rather than a physical process. Considering that the air mass wiggled on 23 December in PE1 combined with SOC increasing in PM\({}_{1}\) fraction, we confidently speculated that a strong aerosol aging process took place during fully mixing with the polluted air from the south of Henan, west of Shandong and south of Hebei in PE1 (Figure S2a). In addition, the proportion of the four components of OC (OC1, OC2, OC3 and OC4) in TC during the formation of pollution was relatively stable in PE1 (Figure 4; since the content of EC3 and optical pyrolyzed OC (py) components are too low and the proportions are negligible, they are not in consideration), which was also a partly proof of the full mixing effect of air masses. \begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline \hline  & \multicolumn{3}{c}{**PE1**} & \multicolumn{3}{c}{**PE2**} & \multicolumn{3}{c}{**PE3**} & \multicolumn{3}{c}{**PE4**} \\ \cline{2-13}
**PE** & **PM\({}_{1}\)** & **PM\({}_{2.5}\)** & **PM\({}_{10}\)** & **PM\({}_{1}\)** & **PM\({}_{2.5}\)** & **PM\({}_{10}\)** & **PM\({}_{1}\)** & **PM\({}_{2.5}\)** & **PM\({}_{10}\)** & **PM\({}_{1}\)** & **PM\({}_{2.5}\)** & **PM\({}_{10}\)** \\ \hline TC (ug\(\cdot\)m\({}^{-3}\)) & 18.29 & 26.92 & 37.78 & 19.90 & 31.62 & 40.50 & 10.46 & 11.46 & 18.52 & 17.57 & 30.82 & 46.26 \\ OC (ug\(\cdot\)m\({}^{-3}\)) & 11 & 20.23 & 28.33 & 12.95 & 23.07 & 28.75 & 6.59 & 7.86 & 12.39 & 11.52 & 22.03 & 34.54 \\ EC (ug\(\cdot\)m\({}^{-3}\)) & 5.54 & 6.71 & 9.70 & 6.95 & 8.54 & 11.76 & 3.60 & 3.87 & 6.14 & 6.06 & 8.79 & 11.72 \\ POC (ug\(\cdot\)m\({}^{-3}\)) & 8.07 & 10.87 & 14.38 & 10.13 & 13.83 & 17.43 & 5.63 & 5.83 & 9.10 & 8.82 & 14.23 & 17.37 \\ PC (ug\(\cdot\)m\({}^{-3}\)) & 13.52 & 17.58 & 24.08 & 17.08 & 22.37 & 29.19 & 9.23 & 9.7 & 15.24 & 14.88 & 23.02 & 29.09 \\ SOC (ug\(\cdot\)m\({}^{-3}\)) & 4.69 & 9.36 & 13.95 & 3.11 & 10.17 & 11.32 & 0.96 & 2.03 & 3.95 & 2.69 & 7.80 & 17.18 \\ SOC/OC & 34\% & 46\% & 45\% & 19\% & 38\% & 37\% & 15\% & 26\% & 23\% & 23\% & 34\% & 42\% \\ TAC/PM & 46\% & 51\% & 28\% & 36\% & 37\% & 26\% & 46\% & 24\% & 23\% & 44\% & 32\% & 26\% \\ OC/EC & 2.22 & 3.06 & 2.77 & 1.85 & 2.83 & 2.42 & 1.80 & 2.19 & 1.98 & 1.92 & 2.48 & 2.72 \\ Char-EC/Soot-EC & 6.97 & 7.88 & 6.77 & 6.54 & 6.87 & 10.13 & 4.74 & 4.24 & 5.39 & 6.82 & 10.67 & 8.52 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Concentration and range of carbonaceous components in PM\({}_{1}\), PM\({}_{2.5}\) and PM\({}_{10}\) in the four PEs. Figure 3: The mass concentration of OC and EC in PM\({}_{1}\), PM\({}_{2.5}\) and PM\({}_{10}\) during the sampling days. EC and POC are both mainly produced by primary emissions [41; 42; 43]. Therefore, summation of EC and POC could be regarded as the primary emission carbon (PC). The mean PC concentrations were 17.08, 22.37 and 29.19 \(\mu\)g\(\cdot\)m\({}^{-3}\) for PM\({}_{1}\), PM\({}_{2.5}\) and PM\({}_{10}\), respectively. The concentration as well as the growth rate of PC in PE2 was clearly higher (4.21 in PM\({}_{1}\), 9.85 \(\mu\)g\(\cdot\)m\({}^{-3}\).day\({}^{-1}\) in PM\({}_{2.5}\) and 7.27 \(\mu\)g\(\cdot\)m\({}^{-3}\).day\({}^{-1}\) in PM\({}_{10}\), respectively) (Table 3).