Abstract
The effect of a passage of land breeze front as a meteorological factor upon high concentration of NOx was analyzed based on the observation data conducted during January, 1983 at Shinjuku Imperial Garden. At the passage of land breeze front, NOx showed high concentration from the surface to a height of several hundred meter, and the region of this high concentration coincides with the head of land breeze. At surface level, NOx concentration also shows quite similar pattern. However, NO2 does not show a significant increase compared with NOx, Ox concentration inside the land-breeze head was almost zero due to the reaction with NO. On the other hand, concentration of Ox above the level of 200 m showed several ten ppb, and the downward transport of Ox may be important at the upper boundary of land breeze head. The occurrence of high concentration of NOx was correlated with the passage of the land breeze front, and the appearance time of peaks in NOx inversely correlated to the N-S distance from the Tokyo Bay area.
