Global Environment

State of the Global Environment at a Glance: Acid Deposition

Acid deposition refers to rain water with a pH of 5.6 or less and atmospheric deposition of acid particles. In recent years, acid rain as severe in nature as that in Europe and North America has been widely observed in Japan.

Acid deposition situation

1) Average value over the five years of the 2nd survey period (Annual values for the years when no measurements were available, or in which data were disregarded under the terms of the annual assessment standard, are not included in the calculation.)
2) For Tokyo, different measuring points were used for the 2nd and 3rd surveys.
3) For Kurahashi, the measuring point in 1994 and later years is different to that used in 1993.
4) For Sapporo, Niitsu, Nonodake and Tsukuba, the measuring frequency for 1994 and later years is different to that for 1993.
5) Data from measuring points that are closed over winter (Oze, Nikko and Akagi) are excluded.