10:45 AM - 11:00 AM
[AAS12-19] Individual particle analysis of marine aerosols collected over the Pacific Ocean and its marginal seas
Keywords:marine atmospheric aerosol, sea-salt, sulfate, volcano, dimethyl sulfide, methanesulfonic acid
Sampling of marine atmospheric aerosol particles was carried out during KH-13-7 cruise (2013/12/11~2014/2/12) and KH-14-3 Leg2 cruise (2014/7/17~8/11) in the Pacific and its marginal seas. Individual particles were analysed using a transmission electron microscope and an energy dispersive X-ray spectrometer.
In most ocean regions, unmodified sea-salt particles accounted for more than 80% of the analysed particles. However, sulfate particles accounted for more than 85% in the sample collected around Guam islands. High concentrations of radon and number of aerosol particles, along with analysis of backward trajectories suggested that polluted air masses originated from the Asian continent came to the observation area. The aerosols collected around the Aleutian Islands included large number of sulfate and modified sea-salt particles. A Na-Cl-S ternary diagram indicates that sea-salt particles were modified with MSA produced from DMS oxidation or H2SO4. Air masses from a volcano transported from the Kamchatka were also the potential source of H2SO4 around the Aleutian island.