The physicochemical characteristics of atmospheric aerosols has varied substantially in recent decades partially due to anthropogenic emissions reductions and is expected to continue to change. Although sustained global emission controls have led to significant environmental improvements, the climate penalty of additional warming by its complex radiative effects have also raised public concern. Here, we found that increasing coarse dust aerosols can strongly stimulate the coagulation of fine particles in Europe. The resulting more and smaller coarse particles effectively scatter solar radiation and cools the climate, mitigating the warming effect caused by fine particle reductions. The changes in coarse mode can offset 19.98% of the weakened cooling effect caused by the changes in fine mode at the bottom of atmosphere from 1999 to 2019. Our results address for the first time the warming effect caused by the fine particle reductions may be mitigated by coarse and fine aerosol interactions.

aerosols; radaitive forcing; aerosol size distribution