LONG-RANGE TRANSPORT OF AEROSOL OVER THE NORTH PACIFIC-OCEAN

The investigation on long-range transport of aerosol particles over th e North Pacific was performed using PIXE. Sampling was carried out on board a large sailing ship, T.S. ''Nippon Maru'', during the cruise ro und the North Pacific from June 21 to August 31 in 1991. Aerosol sampl es were collected with two sets of Battelle-type 10 stage cascade impa ctors in parallel. Radon daughter concentrations were concurrently mea sured in order to obtain the time scale of air mass transport from con tinents using the half-life of radon (3.8 d). The data were compared w ith those obtained by the previous sampling cruises of R/V Hakuho Maru in 1985, 1989 and 1990. Anomalously high concentrations of fine sulfu r (particle size < 1 mum) and silicon were observed around the norther n part of the central North Pacific. Trajectories of air mass suggeste d that the increase of these components were caused hy the big volcani c eruption of Mt. Pinatubo in the Philippine Islands on June 15. 1991.