Abstract
It is a well known fact that acid-rain has caused great damages to plants, forests, soils lakes and rivers. In the snowy regions of Japan, such as Hokuriku, Western part of Tohoku and Hokkaido, there is much snowfall instead of rain between December and March. The quantity of snowfall is eguivalent to almost a quarter of the annual precipitation. For the above reasons, it is important to continuosly monitor the acidity of falling snow and deposited snow in these regions.
We started to measure the pH-value and electrical conductivity for falling snow and deposited snow in February 1992, About two-third of the measured pH-values for falling snow were lower than 5.6 P. H. which is the critical pH-value for acid-rain. The pH-values for deposited snow observed at 7 points in Akita prefecture also showed that falling snow in this winter to be acidsnow, These data suggest that acidity of falling snow is now increasing in the study area.
