抄録
Aircraft observations of atmospheric pollutants were made over the seas between Japan and the Asian continent in five missions since 1991. Continuous SO2 measurements were made in Nov. 1992, March 1994, Dec. 1994, and Nov. 1995. The average concentrations of SO2 were 0.93 and 0.41 ppb at altitudes of less than and greater than 2,000 m, respectively. The vertical distributions of SO2 reflected characteristics intermediate between those of the continental polluted atmosphere and the marine background atmosphere. It was also found that air masses transported from the Asian continent to Japan can be divided into 3 types: (a) China ∼ Yellow Sea ∼ Kyushu: low SO2 and high SO42-/SO2 ratio, (b) Korea ∼ western Japan: high SO2 and low SO42-/SO2 ratio, and (c) North Asia ∼ eastern Japan: low SO2 and low SO42-.
