Observational evidence for the non-suppression effect of atmosphericchemical modification on the ice nucleation activity of East Asian dust br

Airborne mineral dust triggers ice formation in clouds and alters cloud microphysical properties by acting as ice-nucleating particles (INPs), potentially influencing weather and climate at regional and global scales. Anthropogenicpollution would modify natural mineral dust during the atmospheric transport process. However, the effects of anthro-pogenic pollution aging on the ice nucleation activity (INA) of mineral dust remain not well-understood. In this study,we investigated the immersion mode ice nucleation properties and particle chemical characterizations of collectedsize-resolved Asian dust samples (eight particle size classes ranging from 0.18 to 10.0 mu m), and testified the chemicalmodification of aged dust particles via particle chemistry and morphology analyses including the mass concentrationsof particulate matter, the water-soluble ion concentrations, the mental element concentrations, and single-particlemorphology. The mass fraction of Ca2+in element Ca and the mean relative mass proportions of supermicron Ca2+increased by 67.0 % and 3.5-11.2 % in aged Asian dust particles, respectively, suggesting the occurrence of heteroge-neous reactions. On the other hand, the total INP concentrations (totalNINP) and total ice nucleation active site densi-ties (totalns(T)) were consistent between aged and normal dust particles (0.62-1.18 times) without a statisticallysignificant difference. And theNINPandns(T) of chemically aged supermicron dust (1.0-10.0 mu m) in each particlesize class were nearly equal to or slightly higher than those of normal Asian dust, which were 0.70-2.45 times and0.64-4.34 times at-18 degrees C, respectively. These results reveal that anthropogenic air pollution does not notably change the INP concentrations and does not impair the INA of Asian dust. Our work provides direct observational evidenceand clarifies the non-suppression effect of anthropogenic air pollution on the INA of East Asian dust, advancing the un-derstanding of the ice nucleation of airborne aged mineral dust

Automated summary

This study investigated the ice nucleation properties of Asian dust and found that anthropogenic pollution does not significantly change the ice nucleation activity (INA) of Asian dust.