Abstract
To elucidate atmospheric environment at mountainous sites in Hokuriku district, measurement of ozone (O3) concentration was performed at Bijyodaira (altitude, 1000m), mid-slope of Mt. Tateyama during the autumn season (September to November) in 2003. Mean concentration of O3 was 34ppbv. A clear diurnal variation with reaching a maximum during the afternoon was observed until the early October. A maximum concentration in the nighttime occurred in November. The O3 increase in the daytime seems to be caused by transport of air pollution from lower atmosphere and photochemical O3 production. On the other hand, the maximum concentration of O3 at night may be due to air subsidence. The nighttime rising concentration was also observed in the October, therefore, double peaks of O3 were seen in the early October.
