Short term variation of marine organic aerosols under the North-Western Pacific high pressure region in the summer of 1999

To determine the variability of chemical properties in marine aerosols, a stationary shipboard measurement study was carried out at a station over the Northwest Pacific for 29 hours in the summer of 1999. Under a North Pacific high pressure system, carbonaceous substances, major inorganic ions, and particle numbers of typical marine aerosols were measured with little influence from continental and anthropogenic sources. The mass median diameter of organic aerosol was larger than 0.5 μm and its behaviour over time was similar to sea-salt aerosol. Although the source of marine organic aerosol was believed to be mainly from continents, this result suggested that organic substances in micro layer of the sea surface is one of the sources to supply fine organic aerosol to the marine atmosphere. The further investigation would be necessary over various oceanic regions to find out the effects of marine biological activities.