Open AccessIodine speciation and deposition fluxes from the marine atmosphere
Author(s) -
Baker A. R.,
Tunnicliffe C.,
Jickells T. D.
Publication year - 2001
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2000jd000004
Subject(s) - iodate , iodine , iodide , deposition (geology) , aerosol , atmosphere (unit) , environmental chemistry , scavenging , precipitation , chemistry , volatilisation , environmental science , inorganic chemistry , geology , meteorology , organic chemistry , paleontology , physics , sediment , antioxidant
The concentration and speciation of iodine have been determined in wet and dry deposition at a coastal site over a 15‐month period. Deposition fluxes in rain (2.7 μmol m −2 yr −1 ) and aerosol (3.6–6.5 μmol m −2 yr −1 ) are the major routes for removal of iodine from the marine atmosphere onto the Earth's surface, with only a minor contribution from direct deposition of methyl iodide (0.003–0.17 μmol m −2 yr −1 ). Iodate (IO 3 − ) is often considered to be the only species of iodine that is permanently removed to the aerosol phase, and IO 3 − may therefore be expected to be the dominant form of iodine in precipitation. However, iodide (I − ) was found to constitute a significant fraction (5–100%) of iodine in both rain and aerosol. This implies that the rates of iodate formation and iodide volatilization (through reaction with hypohalous acids) are relatively slow. A third pool of aerosol iodine (nonvolatile organic compounds) may also contribute to removal of iodine from the atmosphere in dry or wet deposition.