Electric Vehicles in China: Emissions and Health Impacts

TLDR

E‑bikes are the largest alternative‑fuel vehicle adoption in China, with over 100 million units sold, and e‑car sales are rapidly increasing. The study aims to compare emissions and environmental health impacts of conventional vehicles and electric vehicles in 34 major Chinese cities. The authors evaluate CO₂, PM₂.₅, NOₓ, HC emission factors and primary PM₂.₅ intake fractions for each vehicle type. The analysis shows that e‑cars emit more CO₂ per km than e‑bikes, have lower PM₂.₅ emission factors than gasoline cars but higher intake fractions, resulting in primary PM₂.₅ impacts per passenger‑km that are 3.6 × greater than gasoline cars, 2.5 × lower than diesel cars, and comparable to diesel buses, while e‑bikes produce the lowest impacts, underscoring the role of emission proximity in environmental health assessments.

Abstract

E-bikes in China are the single largest adoption of alternative fuel vehicles in history, with more than 100 million e-bikes purchased in the past decade and vehicle ownership about 2× larger for e-bikes as for conventional cars; e-car sales, too, are rapidly growing. We compare emissions (CO(2), PM(2.5), NO(X), HC) and environmental health impacts (primary PM(2.5)) from the use of conventional vehicles (CVs) and electric vehicles (EVs) in 34 major cities in China. CO(2) emissions (g km(-1)) vary and are an order of magnitude greater for e-cars (135-274) and CVs (150-180) than for e-bikes (14-27). PM(2.5) emission factors generally are lower for CVs (gasoline or diesel) than comparable EVs. However, intake fraction is often greater for CVs than for EVs because combustion emissions are generally closer to population centers for CVs (tailpipe emissions) than for EVs (power plant emissions). For most cities, the net result is that primary PM(2.5) environmental health impacts per passenger-km are greater for e-cars than for gasoline cars (3.6× on average), lower than for diesel cars (2.5× on average), and equal to diesel buses. In contrast, e-bikes yield lower environmental health impacts per passenger-km than the three CVs investigated: gasoline cars (2×), diesel cars (10×), and diesel buses (5×). Our findings highlight the importance of considering exposures, and especially the proximity of emissions to people, when evaluating environmental health impacts for EVs.