Research on the synergistic effect of pollution reduction and carbon reduction in China's new infrastructure construction： Based on the perspective of mismatch of innovation elements

New infrastructure construction is emerging as a key driver for achieving carbon peaking and carbon neutrality in the digital economy era, fostering green, low-carbon, and high-quality economic and social development. Using panel data from 30 provinces (autonomous regions and municipalities) in China from 2007 to 2022, this study measures indicators of new infrastructure development and empirically examines its synergistic effects on pollution reduction and carbon mitigation from the perspective of innovation factor misallocation. The findings indicate that: (1) New infrastructure significantly enhances coordinated governance in pollution reduction and carbon mitigation. This conclusion remains robust after a series of endogeneity and stability tests. However, the synergy between pollution reduction and carbon mitigation is not immediately observable. Only after the new infrastructure development surpasses certain "thresholds" does its effect on pollution and carbon reduction become evident. (2) Mechanism analysis reveals that new infrastructure alleviates the misallocation of R&D personnel, thereby promoting pollution reduction and carbon mitigation. However, the mechanism based on the misallocation of R&D capital has yet to fully manifest its effects. Factors such as R&D personnel mobility, human capital levels, and skill matching are effective in addressing R&D personnel misallocation and unlocking the benefits of technological innovation through new infrastructure, whereas government funding does not show a significant improvement in these outcomes. (3) Further analysis shows that new infrastructure can effectively reduce the "rebound" in carbon emissions currently. Nevertheless, in terms of spatial correlation, the overall impact of new infrastructure on coordinated pollution reduction and carbon mitigation exhibits negative externalities. The conclusions of this study provide a viable pathway for achieving the synergistic effects of pollution reduction and carbon mitigation, contributing to the "dual carbon" goals. These findings also offer empirical support for local governments in actively planning and advancing strategic layouts for new infrastructure.