Rapid Iodine Oxoacids Nucleation Enhanced by Dimethylamine in Broad Marine Regions.

Recent experiment (He et al, 2021, Science) revealed a vital nucleation process of iodic acid (HIO₃) and iodous acid (HIO₂) under the marine boundary layer conditions. However, HIO₃-HIO₂ nucleation cannot effectively derive the observed rapid new particle formation (NPF) in broad marine regions. Dimethylamine (DMA) is a promising basic precursor to enhance nucleation considering its strong ability to stabilize acidic clusters and the wide distribution in marine atmosphere, while its role in HIO₃-HIO₂ nucleation remains unrevealed. Hence, a method combining quantum chemical calculations and Atmospheric Cluster Dynamics Code (ACDC) simulations was utilized to study the HIO₃-HIO₂-DMA nucleation process. We found that DMA can compete with HIO₂ to accept the proton from HIO₃ as a basic precursor in the most stable configurations of HIO₃-HIO₂-DMA clusters. DMA can significantly enhance the cluster formation rates of HIO₃-HIO₂ kinetically for more than 10³-fold in regions with abundant amine and scarce iodine based on combined factors of high nucleation ability and high concentration of DMA. Furthermore, the iodine oxoacids nucleation enhanced by DMA may explain the sources of rapid NPF events under different conditions corresponding to multiple ocean regions, which can provide important inspirations to understand the frequent and intensive NPF events in broad marine regions. [ABSTRACT FROM AUTHOR]