Iodine oxoacids enhance nucleation of sulfuric acid particles in the atmosphere

He, Xu Cheng; Simon, Mario; Iyer, Siddharth; Xie, Hong Bin; Rörup, Birte; Shen, Jiali; Finkenzeller, Henning; Stolzenburg, Dominik; Zhang, Rongjie; Baccarini, Andrea; Dada, Lubna; El Haddad, Imad; Lamkaddam, Houssni; Marten, Ruby; Surdu, Mihnea; Wang, Dongyu; Baltensperger, Urs; Kulmala, Markku

doi:10.1126/science.adh2526

Iodine oxoacids enhance nucleation of sulfuric acid particles in the atmosphere

He XC, Simon M, Iyer S, Xie HB, Rörup B, Shen J, Finkenzeller H, Stolzenburg D, Zhang R, Baccarini A, Dada L, El Haddad I, Lamkaddam H, Marten R, Surdu M, Wang D, Baltensperger U, Kulmala M, et al.

Citation

He, X. C., Simon, M., Iyer, S., Xie, H. B., Rörup, B., Shen, J., … Kulmala, M. (2023). Iodine oxoacids enhance nucleation of sulfuric acid particles in the atmosphere. Science, 382(6676), 1308-1314. https://doi.org/10.1126/science.adh2526

Persistent URL https://www.dora.lib4ri.ch/psi/islandora/object/psi:57765

The main nucleating vapor in the atmosphere is thought to be sulfuric acid (H₂SO₄), stabilized by ammonia (NH₃). However, in marine and polar regions, NH₃ is generally low, and H₂SO₄ is frequently found together with iodine oxoacids [HIO_x, i.e., iodic acid (HIO₃) and iodous acid (HIO₂)]. In experiments performed with the CERN CLOUD (Cosmics Leaving OUtdoor Droplets) chamber, we investigated the interplay of H₂SO₄ and HIO_x during atmospheric particle nucleation. We found that HIO_x greatly enhances H₂SO₄(-NH₃) nucleation through two different interactions. First, HIO₃ strongly binds with H₂SO₄ in charged clusters so they drive particle nucleation synergistically. Second, HIO₂ substitutes for NH₃, forming strongly bound H₂SO₄-HIO₂ acid-base pairs in molecular clusters. Global observations imply that HIO_x is enhancing H₂SO₄(-NH₃) nucleation rates 10- to 10,000-fold in marine and polar regions.