Long term trend in the chemical composition of wet deposition in Metropolitan Tokyo.

Abstract

The long term trend in chemical composition of precipitation was examined in three different areas of metropolitan Tokyo from 1992 to 2005. As a result, it was discovered that the NO₃^- quantity was 26.3 meq/m² in the coastal area, 32.6 meq/m² in the hilly area, and 31.0 meq/m² in the mountainous area. The equivalent ratio of non sea-salt sulfate to nitrate in the precipitation was higher in the mountainous area than in the coastal area due to NO₃^- that was transported from the coastal area.