Chamber studies of iodine chemistry in the atmosphere

W.J. BLOSS; J.J. NAJERA; S. BLEICHER; A. HELD; C. ZETZSCH; J. BUXMANN; S. SCHMIDT; U. PLATT

Bayreuth

Workshop; HALOPROC Germany meeting; 2013

EUROCHAMP

Iodine chemistry has been shown to occur through much of the marine boundary layer (MBL), and may also be present in regions of the free troposphere. Photolysis and/or chemical processing of emitted iodine species leads to the release of the constituent iodine atoms and formation of IO radicals. Subsequent reactions of IO can lead to catalytic ozone destruction, affect the abundance of atmospheric species such as HOx and NOx, and result in new particle formation and/or growth. However, there are major uncertainties in our knowledge of the iodine chemical reaction system, which limit our ability to accurately quantify these impacts using atmospheric models. The aim of the CHICA project was to apply a large simulation chamber (Bayreuth) coupled with new analytical instrumentation to study the integrated gas-phase iodine system under near-atmospheric conditions, and so address specific uncertainties identified in the gas-phase kinetics / photochemistry.