Co-drivers of air pollutant and CO2 emissions from on-road transportation in China 2010-2020

The sustained growth in on-road transportation demand poses an increasing challenge for countries in mitigating air pollution and addressing climate change. Revealing how varying socioeconomic and policy factors have contributed to synergies or trade-offs between CO₂ and air pollution emissions is crucial for effectively co-controlling carbon-pollution emissions. Here, based on detailed air pollution and CO₂ emission inventories from China’s on-road transportation over 2010-2020 and the Logarithmic Mean Divisia index (LMDI) analysis, we explore the on-road synergetic evolution trends among pollution and CO₂ emissions and identify the co-drivers influencing carbon-pollution co-emissions. We find that the estimated sectoral emissions of VOCs, NO_x, PM_2.5, and CO declined by 49.9%, 25.9%, 75.2%, and 63.5%, respectively, while CO₂ emissions increased by 46.1% in China over 2010-2020. The vehicle-type-specific analysis further highlights the crucial role of light-duty passenger vehicles and heavy-duty trucks in simultaneously improving air quality and mitigating CO₂ emissions, given their synergies in emission growth of VOCs-CO₂ and NO_x-CO₂, respectively. The driver analysis indicates that socioeconomic growth and rising transportation demand are major co-drivers of carbon-pollution emission growth, while the implementation of control policies, particularly advances in emission efficiency, can facilitate co-reductions. Specifically, in the passenger subsector, advances in emission efficiency and changes in travel behavior are identified as the most efficient co-drivers for synergistic emission reduction. The gradual proliferation of new energy vehicles also provides additional synergistic reductions. In the freight subsector, improved freight economic efficiency and optimized freight transport structure are identified as other two co-drivers of synergistic emission reduction. Regional disparities further emphasize the need for policy refinement, including reducing dependency on fuel vehicles in the passenger subsector and prioritizing co-reduction strategies in high-emission provinces in the freight subsector. Overall, our study confirms the effectiveness of China’s on-road control policies and provides valuable insights for future policy makers in China and other similarly positioned developing countries seeking to reduce CO₂ and air pollutant emissions simultaneously.