佐渡島と新潟県内陸の山岳におけるオゾン濃度の垂直変化と季節変動

Abstract

From April to November in 2008, we observed altitudinal and seasonal changes in the monthly mean ozone concentrations using passive samplers at two mountains in Niigata Prefecture: Mt. Bunagahira on Sado Island and Mt. Hakkai, located on the mainland. The mean ozone concentrations at both mountains were the highest in spring (May), and decreased in summer. The ozone concentrations at Mt. Bunagahira increased in autumn again. Such a seasonal change in the mean ozone concentrations was the same pattern observed at other mountains in central Japan as well as plains in western part of Japan. The monthly mean ozone concentrations increased with the altitude at Mt. Hakkai. Such an altitudinal change in ozone concentrations was the similar pattern observed at other mountains in central Japan. In contrast, the mean ozone concentrations of each month showed similar values at all altitudes on each slope side of Mt. Bunagahira showing a different tendency with other mountains observed in Japan. This phenomenon might be resulted from few local origins of air pollutants around Mt. Bunagahira that generate or decompose ozone. The mean ozone concentrations on the slope of Mt. Bunagahira facing northwest were higher than those facing southeast in every month. This phenomenon might suggest that the mean ozone concentrations transported from the direction of East Asian continent were higher than those of the mainland in Niigata Prefecture.