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Enhancement of Atmospheric Nucleation Precursors on Iodic Acid-Induced Nucleation: Predictive Model and Mechanism

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  • Fangfang Ma
  • Hong-Bin Xie, Dalian University of Technology
  • ,
  • Rongjie Zhang, Dalian University of Technology
  • ,
  • Lihao Su, Dalian University of Technology
  • ,
  • Qi Jiang, Dalian University of Technology
  • ,
  • Weihao Tang, Guangdong Academy of Sciences
  • ,
  • Jingwen Chen, Dalian University of Technology
  • ,
  • Morten Engsvang
  • Jonas Elm
  • Xu-Cheng He, University of Helsinki

Iodic acid (IA) has recently been recognized as a key driver for new particle formation (NPF) in marine atmospheres. However, the knowledge of which atmospheric vapors can enhance IA-induced NPF remains limited. The unique halogen bond (XB)-forming capacity of IA makes it difficult to evaluate the enhancing potential (EP) of target compounds on IA-induced NPF based on widely studied sulfuric acid systems. Herein, we employed a three-step procedure to evaluate the EP of potential atmospheric nucleation precursors on IA-induced NPF. First, we evaluated the EP of 63 precursors by simulating the formation free energies (ΔG) of the IA-containing dimer clusters. Among all dimer clusters, 44 contained XBs, demonstrating that XBs are frequently formed. Based on the calculated ΔG values, a quantitative structure-activity relationship model was developed for evaluating the EP of other precursors. Second, amines and O/S-atom-containing acids were found to have high EP, with diethylamine (DEA) yielding the highest potential to enhance IA-induced nucleation by combining both the calculated ΔG and atmospheric concentration of considered 63 precursors. Finally, by studying larger (IA)1-3(DEA)1-3 clusters, we found that the IA-DEA system with merely 0.1 ppt (2.5×106 cm-3) DEA yields comparable nucleation rates to that of the IA-iodous acid system.

Original languageEnglish
JournalEnvironmental Science & Technology
Pages (from-to)6944-6954
Number of pages11
Publication statusPublished - May 2023

    Research areas

  • Amines, Atmosphere/chemistry, Gases, Iodates

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