Natural aerosols play a central role in the Earth system. The conversion of dimethyl sulfide to sulfuric acid is the dominant source of oceanic secondary aerosol. Ocean emitted iodine can also produce aerosol. Using a GEOS-Chem model we present a simulation of iodine aerosol. The simulation compares well with the limited observational dataset. Iodine aerosol concentrations are highest in the tropical marine-boundary layer (MBL) averaging 5.2 ng (I) m-3 with monthly maximum concentrations of 90 ng (I) m-3. These masses are small compared to sulfate (0.75% of MBL burden, up to 11% regionally) but are more significant compared to DMS sourced sulfate (3% of the MBL burden, up to 101% regionally). In the pre-industrial, iodine aerosol makes up 0.88 % of the MBL burden sulfate mass and regionally up to 21%. Iodine aerosol may be an important regional mechanism for ocean-atmosphere interaction.
- dimethyl sulfide
- marine boundary layer