Speciation of iodine in marine aerosol

We have compiled a comprehensive dataset of field observations of iodine speciation and size distribution in marine aerosol (1983-2018). Since the source of iodine is mainly marine, only ship-borne campaigns (16 cruises) and coastal or insular campaigns (12 ground-based stations) have been considered. Iodine speciation measurements are heterogeneous and do not always cover the same species or group of species. The data can be classified in five groups according to the iodine species reported and their size segregation in fine and coarse aerosol: (1) total iodine (TI) and total soluble iodine (TSI) in bulk aerosol, (2) TI size distribution, (3) TSI and soluble speciation size distribution, (4) soluble speciation in fine aerosol fraction only and (5) soluble speciation in bulk aerosol only. Soluble speciation consist of iodide (I^-), iodate (IO₃^-) and soluble organic iodine (SOI). For some of the cruises where the size distribution of soluble iodine species was reported (7 cruises) there are also measurements of major ions (MI) available. MI observations include Na⁺, NH₄⁺, Mg²⁺, Ca²⁺, K⁺, Cl^-, NO₃^-, SO₄^2-, oxalate (C₂O₄^-2), Br^- and methanesulfonate (CH₃SO₃^-), and derived quantities such as non-sea-salt (nss) K⁺, Ca²⁺ and SO₄^2-. The associated paper discusses some aspects of data treatment and questions related to analytical methods employed to determine iodine speciation.