Long term trend of chemical constituents in Tokyo metropolitan area in Japan

Yasushi Narita, Kei Satoh, Keiichi Hayashi, Tamami Iwase, Shigeru Tanaka, Yukiko Dokiya, Morikazu Hosoe, Kazuhiko Hayashi

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


In recent years, acid rain has been a social problem all over the world. In Japan, it is also a big problem especially in the metropolitan area. Then, we have measured major ions such as H+, Na+, NH4+, K+, Mg2+, Ca2+, Cl-, NO3-, and SO42- in precipitation and dry deposition samples which had been collected at 9 sampling sites at Hiyoshi, Mita, Kashiwa, Shiki, Fujisawa, Yokosuka, Mitaka, Hachiouji, and Ashikaga in Tokyo Metropolitan area for 10 years since 1990. The average pH of precipitation in their sites was 4.56 (n=1906). As the results of multiple regression analysis showed that pH of precipitation was determined by 5 ions such as NH4+, nssCa2+ (non sea salt calcium), nssCl-(non sea salt chloride), NO3-, nssSO42-(non sea salt sulfate) in the most of the sampling sites. Therefore, it is very important to investigate the behavior of these ions to understand the acidification of rain in Tokyo Metropolitan area. In this study, a long term trend of each ion concentration in precipitation and wet deposition was also investigated the base on the data we had observed at 7 sites for 10 years by the statistical method.

Original languageEnglish
Pages (from-to)1649-1654
Number of pages6
JournalWater, Air, and Soil Pollution
Issue number1-4 III
Publication statusPublished - 2001
Externally publishedYes


  • Chemical constituents
  • Long term trend
  • Network observation
  • Precipitation
  • Tokyo Metropolitan area
  • Wet deposition

ASJC Scopus subject areas

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


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