Impact of sea water photochemistry on aerosol particles formation

MARÍA EUGENIA MONGE; HARTMUT HERRMANN; CHRISTIAN GEORGE

San Francisco

Conferencia; AGU Fall Meeting 2011; 2011

American Geophysical Union

The sea surface microlayer is an organic-enriched layer present at the air-sea interface and presents different physical and chemical properties than subsurface waters. Photoactive organic compounds of the sea surface microlayer may participate in the photooxidation of aqueous halides, becoming a source for halogen species to the atmosphere. We report here the results of laboratory studies based on the photochemistry of sea water proxies containing light absorbing organic compounds as source of precursors of atmospheric oxidants. We studied the influence of halides and humic acid on the photoinduced formation of aerosol particles from SO2 oxidation. Sea water proxies consisted on aqueous solutions of sodium chloride, sodium bromide, sodium iodide, and humic acid. The solutions were irradiated with a Xe lamp while exposed to an air flow in a first reactor. The flow exiting the latter was introduced into an aerosol flow tube reactor and mixed with traces of SO2. The generation of aerosol particles was followed as a function of time and irradiation in both reactors using a Condensation Particle Counter. Aerosol particles formation from SO2 oxidation was observed when the SO2 flow in the aerosol flow reactor was mixed with the air flow exiting the irradiated solution. These results may be relevant to the climate impact of marine boundary layer aerosols.