Role of Iodine Recycling on Sea‐Salt Aerosols in the Global Marine Boundary Layer

Abstract

Heterogeneous uptake of hypoiodous acid (HOI), the dominant inorganic iodine species in the marine boundary layer (MBL), on sea‐salt aerosol (SSA) to form iodine monobromide and iodine monochloride has been adopted in models with assumed efficiency. Recently, field measurements have reported a much faster rate of this recycling process than previously assumed in models. Here, we conduct global model simulations to quantify the range of effects of iodine recycling within the MBL, using Conventional, Updated, and Upper‐limit coefficients. When considering the Updated coefficient, iodine recycling significantly enhances gaseous inorganic iodine abundance (∼40%), increases halogen atom production rates (∼40% in I, >100% in Br, and ∼60% in Cl), and reduces oxidant levels (−7% in O3, −2% in OH, and −4% in HO2) compared to the simulation without the process. We appeal for further direct measurements of iodine species, laboratory experiments on the controlling factors, and multiscale simulations of iodine heterogeneous recycling.

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“…Furthermore, ref. 99 demonstrated satisfactory modelling of O 3 , as well as for the global sea-salt aerosol abundance in the marine boundary layer compared with global observational results; ref. 39 validated the modelled CH 4 , OH and reactive chlorine species against previous reports.…”

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