## 4 Results analysis  
### Analysis of Vehicular Emissions of BTH Region  
Several policies on vehicular emission mitigation, such as the development of EVs, EV power sources and vehicular emission standards, have been proposed by the government of China. In this study, five scenarios labeled S1-S5 were designed to analyze the potentials of different emission mitigation strategies and policies for reducing vehicular emissions (NOx, HC, CO, and PM) in the  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline  & & **CO** & **NOX** & **HC** & **PM** \\ \hline \multirow{2}{*}{**HDV**} & China-V & 300 & 4610 & 35 & 100 \\  & China-VI & 300 & 4610 & 35 & 100 \\ \hline \multirow{2}{*}{**LDV**} & China-V & 1400 & 60 & 230 & 5 \\  & China-VI & 700 & 35 & 115 & 5 \\ \hline \multirow{2}{*}{**LDT**} & China-V & 5800 & 60 & 1200 & 5 \\  & China-VI & 2900 & 35 & 600 & 5 \\ \hline \multirow{2}{*}{**HDT**} & China-V & 200 & 3530 & 35 & 100 \\  & China-VI & 200 & 3530 & 35 & 100 \\ \hline \multirow{2}{*}{**Other**} & China-V & 2750 & 150 & 855 & 20 \\  & China-VI & 2750 & 150 & 855 & 20 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Vehicular emission factors with different emissions standards (mg/km\(\bullet\)unit).  
\begin{table}
\begin{tabular}{c c c c} \hline \hline  & **Period** & **Period** \\ \hline \multicolumn{4}{c}{**Electricity demand (10\({}^{9}\) kWh)**} \\ \hline Low demand level & [517.71, 537.71, 557.71] & [553.82, 573.82, 593.82] & [594.67, 614.67, 634.67] \\ Medium demand level & [547.25, 567.25, 587.25] & [595.73, 615.73, 635.73] & [636.18, 656.18, 676.18] \\ High demand level & [559.07, 579.07, 599.07] & [646.05, 666.05, 686.05] & [686.87, 706.87, 726.87] \\ \hline \multicolumn{4}{c}{**Electricity generation target (10\({}^{9}\) kWh)**} \\ \hline Coal-fired power & [221.07, 279.81] & [213.27, 268.01] & 208.93, 269.50] \\ Gas-fired power & [58.41, 63.41] & [76.91, 80.91] & [91.88, 95.88] \\ Wind & [40.19, 49.55] & [45.79, 56.48] & [51.01, 61.94] \\ Solar power & [1.20, 1.70] & [3.20, 3.60] & [5.99, 6.22] \\ \hline \multicolumn{4}{c}{**Energy consumption amounts per unit of electricity production**} \\ \hline Coal (ton of SCE/10\({}^{3}\) kWh) & 30.50 & 30.50 & 30.50 \\ Natural gas (m\({}^{3}\)/10\({}^{3}\) kWh) & 142.80 & 142.80 & 142.80 \\ \hline \multicolumn{4}{c}{**Coal consumption amounts per unit of coke processing (ton of SCE/ton)**} \\ \hline \multicolumn{4}{c}{1.35} \\ \hline \multicolumn{4}{c}{**Energy consumption amounts for unit of heat processing (ton of SCE/10\({}^{9}\) kJ)**} \\ \hline \multicolumn{4}{c}{36.00} \\ \hline \hline \end{tabular}
\end{table}
Table 3: Electricity demand and technological data.  
BTH region. Table 4 gives the parameter settings of the different scenarios. Following is a description of each scenario:  
**S1:** Without consideration of EVs, and with the local governments implementing the China V vehicular emission standard.  
**S2:** With consideration of EVs, which account for 1.5% of the LDVs population. EV power sources are 100% based on coal-based power, and the China V vehicular emission standard is implemented.  
**S3:** With consideration of EVs, which account for 1.5% of the LDVs population. EV power sources are based 50% on coal-based and 50% on renewable power. It is assumed that coal-based power is local coal-based power, and renewable power included wind, solar power and imported electricity. The China V vehicular emission standard is implemented.  
**S4:** With consideration of EVs, which account for 1.5% of the LDVs population and with power sources based 100% on renewable energy. The China V vehicular emission standard is implemented.  
**S5:** With consideration of EVs, which account for 1.5% of the LDVs population and with power sources based 100% on renewable energy. The China VI vehicular emission standard (gasoline standard) is implemented.