Iodine observed in new particle formation events in the Arctic atmosphere during ACCACIA

J.D. ALLAN; P.I. WILLIAMS; J.J. NAJERA; J.D. WHITEHEAD; M.J. FLYNN; J.W. TAYLOR; D. LIU; E. DARBYSHIRE; L. CARPENTER; R. CHANCE; S.J. ANDREWS; S.C. HACKENBERG; G. MCFIGGANS

ATMOSPHERIC CHEMISTRY AND PHYSICS

COPERNICUS PUBLICATIONS

Lugar: Gottingen; Año: 2015 vol. 15 p. 5599 - 5609

1680-7316

Accurately accounting for new particle formation(NPF) is crucial to our ability to predict aerosol numberconcentrations in many environments and thus cloud properties,which is in turn vital in simulating radiative transferand climate. Here we present an analysis of NPF events observedin the Greenland Sea during the summertime as part ofthe Aerosol-Cloud Coupling And Climate Interactions in theArctic (ACCACIA) project. While NPF events have been reportedin the Arctic before, we were able, for the first time, todetect iodine in the growing particles using an Aerosol MassSpectrometer (AMS) during a persistent event in the regionof the coastal sea-ice near Greenland. Given the potency ofiodine as a nucleation precursor, the results imply that iodinewas responsible for the initial NPF, a phenomenon that hasbeen reported at lower latitudes and associated with moleculariodine emissions from coastal macroalgae. The initialsource of iodine in this instance is not clear, but it was associatedwith air originating approximately 1 day previously overmelting coastal sea-ice. These results show that atmosphericmodels must consider iodine as a source of new particles inaddition to established precursors such as sulfur compounds.