Distinct PM2.5-related near-term climate penalties induced by different clean air measures in China

The reduction in aerosols often exacerbates climate warming. It remains unclear how to effectively alleviate PM_2.5 pollution while minimizing the penalty on climate warming. Here we identify the clean air measures in China that are associated with low aerosol climate penalty efficiency (ACPE), which is defined as aerosol radiative forcing per unit PM_2.5 concentration reduction. The measures in transportation, residential combustion, and open burning sectors generally caused lower ACPE than those from other sectors. This is ascribed to relatively small decreases in cloud concentration nuclei per unit PM_2.5 reduction in these sectors, which is further attributed to either relatively low aerosol hygroscopicity or relatively small decreases in aerosol number. The specific measures with the lowest ACPE that should be implemented in priority include the promotion of clean energy and tightened emission standards for on-road and off-road vehicles, the prohibition of open burning, and the promotion of clean residential energy.