| Abstrakt: |
Although sulfuric acid (SA) and dimethylamine (DMA) driven nucleation mainly dominants the new particle formation (NPF) process in the atmosphere, seeking the involvement of other gaseous species remains crucial to better understand the NPF. Organosulfate has been detected in gas phase and abundantly in atmospheric fine particles. However, its molecular formation mechanism and its impact on the NPF are still much less understood. Here, we explored the gas phase reaction of Glycolic acid (GA) with SO3, and evaluated the enhancing potential of its products on the SA-DMA driven NPF using a combination of quantum chemical calculations and kinetics modeling. We found that the considerable concentration of glycolic acid sulfate (GAS) is thermodynamically accessible from the reaction of GA with SO3, efficiently catalyzed by SA or H2O molecules. The produced GAS can form stable clusters with SA and DMA, and speeds up the nucleation rate of SADMA system obviously. Notably, the enhancement by GAS on the SA-DMA-based particle formation rate can be up to ~ 800 times in the region where the concentration of SA is about 104 molecules cm-3. Supported by observations of atmospheric NPF events at Mt. Tai in China, our proposed ternary GAS-SA-DMA nucleation mechanism further indicates that the organosulfates produced from the consumption of SO3 may play an important role for the unexpected high NPF rates observed in areas with relatively low concentrations of SA. The presented reaction and nucleation mechanisms provide a new feasible source of organosulfates in atmospheric new particles. Based on our findings, the impact of organosulfates on the atmospheric NPF in multiple regions around the world was estimated and discussed. [ABSTRACT FROM AUTHOR] |
