9415559 Keene The chemistry of inorganic chlorine and its influence on oxidation processes in the marine boundary layer (MBL) are very uncertain. Indirect evidence suggests that C1 atoms may be important oxidants over the world's oceans. In addition, recent field measurements reveal significant concentrations of inorganic C1 gases other than HC1 (probably HOC1 and/or C12) in the MBL. C1 atom precursors are thought to originate from reactions involving sea-salt aerosol (or possibly sea ice in polar regions), but mechanisms of sea-salt dechlorination are poorly understood. This study will assess the influence of inorganic chlorine chemistry on the cycling of ozone, non-methane hydrocarbons (NMHCs), sulfur, and nitrogen in the MBL. Specific research objectives include: 1) To measure simultaneously principal reactant and product species and related physical properties involved in MBL chlorine chemistry; 2) To test hypothesized mechanisms that dechlorinate sea-salt aerosol; 3) To assess the relative importance of C1 atoms and OH radicals as oxidants in the MBL; 4) To search for unique product compounds generated by C1 atom reactions; and 5) To model inorganic C1 chemistry and its contribution to oxidizing capacity in the MBL. Air will be intensively sampled during approximately 10 diel cycles over a 4-week period at the Atmosphere/Ocean Chemistry Experiment (AEROCE) sampling station on Bermuda. Reactive trace gases (HC1*, C12*, HOC1*, NMHCs, organic halides, SO2, NHO3, NO, NOx, NOy, O3, and CO), the chemical composition (major ions and trace elements) of size-segregated aerosol, a variety of tracers, and troposphere meteorology will be measured.
