Long-term trends in the chemical composition of precipitation over western Japan

Shin Ichi Fujita*, Akira Takahashi, Hiroshi Hayami, Tatsuya Sakurai

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


Wet deposition monitoring was conducted at six rural stations in western Japan, during the period from 1987 through 1996. Long-term trends in the concentration of non-sea salt ions were analyzed on the basis of the data obtained. The monitoring results indicated that annual average concentrations of NO3- and NH4+ in precipitation significantly increased on the order of 45%, and that of nss-Ca2+ and nss-SO42-, concentrations did not change over the past 10 years. The ratio of NO3-/nss-SO42- in precipitation significantly increased, the ratio of NO3-/NH4+ showed no marked fluctuations, and the ratio of [nss- Ca2++NH4+]/[nss-SO42-+ NO3-] slightly increased during the period. These findings suggested that the wet deposition of NO3- and NH4+ in western Japan, particularly that in the winter season, was influenced by the long-range transport of nitrogen oxides and ammonia from the Asian continent.

Original languageEnglish
Pages (from-to)415-420
Number of pages6
JournalWater, Air, and Soil Pollution
Issue number1-4 II
Publication statusPublished - 2001
Externally publishedYes


  • Ammonium
  • Long-term trend
  • Nitrate
  • Western Japan
  • Wet deposition

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Ecological Modelling
  • Water Science and Technology
  • Pollution


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