The inharmonious mechanism of CO₂, NO_x, SO₂, and PM_2.5 electric vehicle emission reductions in Northern China

Beijing benefits from the promotion of electric vehicles (EVs) in the improvement of road tailpipe emissions; these emissions are caused by internal combustion engine vehicles (ICEVs) and reduce the surrounding environmental quality. When analyzing the electricity grid, upstream emissions of EVs in Beijing can be tracked back to Shanxi and Inner Mongolia. This study investigates the inharmonious mechanism of emission reduction to promote EVs in Beijing and Northern China based on 6 scenarios and 42 real EVs. Because there is a neighbor effect, Beijing only accounts for 34%, 34%, 41%, and 35% of the total CO₂, NO_x, SO₂ and PM_2.5 emissions, respectively. Although the local CO₂, NO_x, and PM_2.5 emissions can be easily reduced (as long as the conversion of “coal to gas” plan is realized), it is difficult to achieve emission reductions of NO_x and SO₂ without increasing the clean electricity generation mix in Shanxi and Inner Mongolia at the total emission level. However, there is still a large reduction potential of EVs themselves due to an increasingly clean electricity mix in Beijing, Shanxi and Inner Mongolia. Beijing local CO₂, NO_x, SO₂ and PM_2.5 emissions can be reduced by 86.92%, 98.79%, 99.98% and 99.94%, respectively, and a total reduction of 78.43% of CO₂, 93.83% of NO_x, 97.85% of SO₂ and 99.26% of PM_2.5 emissions is possible. Compared with the corresponding ICEV, an EV of 18 kWh/100 km starts to reduce Beijing local CO₂, NO_x and PM_2.5 emissions in scenario 1, 3 and 1, respectively, while the SO₂ emissions cannot be reduced. However, the total CO₂, NO_x, SO₂ and PM_2.5 emissions can be reduced in scenario 2, 5, 5, and 1, respectively. A sensitivity analysis shows that the promotion of EVs can reduce Beijing local CO₂, NO_x, SO₂ and PM_2.5 emissions by 125.568–238.960 g/km, 0.059–0.113 g/km, −0.00003 - - 0.00007 g/km and 0.034–0.065 g/km, respectively. In addition, the total CO₂, NO_x, SO₂ and PM_2.5 reduction in emissions can be 132.883–253.757 g/km, 0.189–0.361 g/km, 0.299–0.569 g/km and 0.053–0.101 g/km, respectively.