Marine　aerosols　play　an　important　role　in　the　global　aerosol　system.In　polluted　coastal　regions,ultra-fine　particles　have　been　recognized　to　be　related　to　iodine-containing　species　and　is　more　serious　due　to　the　impact　of　atmospheric　pollutants.Many　previous　studies　have　identified　iodine　pentoxide(I2O5,IP)to　be　the　key　species　in　new　particles　formation(NPF)in　marine　regions,but　the　role　of　IP　in　the　polluted　coastal　atmosphere　is　far　to　be　fully　understood.Considering　the　high　humidity　and　concentrations　of　pollutants　in　the　polluted　coastal　regions,the　gas-phase　hydration　of　IP　catalyzed　by　sulfuric　acid(SA),nitric　acid(NA),dimethylamine(DMA),and　ammonia(A)have　been　investigated　at　DLPNO-CCSD(T)//ωB97X-D/aug-cc-pVTZ+aug-cc-pVTZ-PP　with　ECP28MDF(for　iodine)level　of　theory.The　results　show　that　the　hydration　of　IP　involves　a　significant　energy　barrier　of　22.33　kcal/mol,while　the　pollutants　SA,NA,DMA,and　A　all　could　catalyze　the　hydration　of　IP.Especially,with　SA　and　DMA　as　catalysts,the　hydration　reactions　of　IP　present　extremely　low　barriers　and　high　rate　constants.It　is　suggested　that　IP　is　unstable　under　the　catalysis　of　SA　and　DMA　to　generate　iodic　acid,which　is　the　key　component　in　NPF　in　marine　regions.Thus,the　catalytic　hydration　of　IP　is　very　likely　to　trigger　the　formation　of　iodine-containing　particles.Our　research　provides　a　clear　picture　of　the　catalytic　hydration　of　IP　as　well　as　theoretical　guidance　for　NPF　in　the　polluted　coastal　atmosphere.