The Acid Rain Observed on Ground Level in Japan

A Review of Mayor Recent Issues and Problems

Abstract

In Japan, acid rain has been recognized to be significant since drizzling injured people's eyesand caused skin irritation during the rainy seasons of 1973 to 1975 in the Kanto and Chubu Districts. Later, the acid rain has become one of a most global environmental problem, so, precipitation chemistry data were obtained in Phase-1 Study of Acid Precipitation Survey over Japan from 1984 to 1988 by Japan Environment Agency. Annual mean pH value over Japan was about 4.6 (4.5 4.7) and the value was not changed significantly in the past decade. The acidity of rainwater was caused by H₂SO₄ and HNO₃ mainly, but in the urban areas, the acidity was neutralized by alkaline species, such as NH₃ and Ca²⁺ species. We notice that the precipitation chemistry data obtained in many sites are useful to make clear the effects of acid rain on terrestrial ecosystems.