Abstract
Observed ground level concentrations of sulfur dioxide (SO2) often exceed 100ppb in the southern part of Kyushu. These high concentration phenomena are analyzed in connection with observed concentrations of SO2 and upper air observations data, surface weather charts and satellite photographs. It is found that high concentration events of SO2 can be much observed during the daytime when mixing layer has developed. It is confirmed that the volcanic SO2 emitted from Mt.Sakurajima has a significant contribution to high concentration events of SO2 in the southern area of Kyushu. Concentrations at the monitoring stations inside Sakurajima island show the high values to the extreme degree. For the other monitoring stations, the influence of volcanic plume from Mt.Sakurajima is small as the distance from Mt. Sakurajima becomes long.
