2004 Volume 19 Issue 2 Pages 117-121
Measurements of particle number density and particulate carbonaceous substances were conducted during the pre ACE-Asia cruise from June 13 to July 5, 2000. This was the preliminary cruise for the Japanese ACE-Asia cruise, covering the western North Pacific region including regions affected by the westerlies, tropical and subtropical regions. Air quality was clearly divided by the Bai-u front (a seasonal frontal system) , with high concentrations of anthropogenic aerosols north of the frontal system and low concentrations to the south. The position of the front and the development of Pacific anticyclone are the primary factors that influence outbreaks of polluted air masses over the western North Pacific in early summer. Relatively high concentrations of organic carbon were also detected over the tropical region, suggesting emission of precursor gases for particulate organic carbon from the ocean. The size-distribution of particle number density suggests that new particle production is activated over the tropical ocean.
