Abstract
This study was performed by use of oxidant data obtained at Mt. Unzen Nodake (1, 142 m) and Miiraku in Goto islands from April to September in 1981 and at the 24 monitoring stations in the Nagasaki prefecture during 1981-1984.
The results of the study were summarized as follows:
1) Oxidant concentration obtained at Mt. Unzen Nodake showed background ozone concentration from April to September in the period of observation.
2) Ozone destruction by NO and deposition to the surface was suggested. Oxidant between June and September was formed from NOx from man-made sources by photochemical reactions. As a results of these effects, oxidant concentrations showed various levels and time variation depending on the location of the stations.
3) The stations were grouped into 5 categories according to NOx concentration and patterns of diurnal variation of oxidant concentration.
4) Variation of background ozone concentration obtained Mt. Unzen Nodake and Isanoura (monitoring station) correlated with variation of surface pressure pattern. 10 typical patterns of them were observed.
