With the in-depth promotion of low-carbon economic transformation and air pollution control, the role of synergetic control of CO₂ and air pollutant emissions has begun to stand out. Based on panel data for 30 provinces in China from 2012 to 2020, we measured the coupling and coordination degree of CO₂ and air pollutant emissions control (CCD) and revealed the direct effect of human capital on CCD, the heterogeneous effect, and the threshold effect of R&D intensity. The results of the study showed that, firstly, CCD at the provincial level in China showed a stepped-up trend and regional heterogeneity. Second, human capital had a significant positive effect on CCD, and this effect was stronger in the “Four Provinces of Shan-He” and Inland provinces. Third, R&D intensity played a significant threshold role in the impact of human capital on CCD, but there was a “medium-term trap”. Therefore, based on the development of differentiated synergistic strategies for pollution and carbon reduction, financial investment in human capital and R&D activities should be increased.