<論文>千葉県北部における酸性雨の地域的特性について : 1994年度観測結果

概要

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In order to make clear the regional characteristics of acid rain in Chiba Prefecture, the data of rainfall obtained during the period from April 1994 to March 1995 by the students of Chiba Keiai Junior College and the environmental monitoring volunteers of the Institute of Environ- mental Studies of the College have been analyzed. The results of the analyses are summarized as follows : 1) Data points where the annual mean pH values of rain samples collected from every rain event in the study period are less than 5.0 are distributed in the area from Sakura to Omigawa. 2) The ion concentration has a tendency to increase in the cold season. 3) Annual mean values of NO_3^- /nssSO_4^<2->(NS ratio) concentration ratio are higher than 0.7 in the area which is encircled by Yotsukaido, Togane, Narita and Choshi. On the other hand, in the northern and the southern parts of the study area, the values decreased to 0.4-0.5. 4) Data points where the NS ratio higher than 1.0 appeared more than 20 per cent in a year, is distributed in the area from Sakura to Omigawa. 5) Whereas the annual mean values of (NH4^+ +Ca^<2+>) (NO_3^-/nssSO_4^<2->) concentration ratio are less than 1.0 to the north of Sakura-Choshi line, the values increase toward the south of this line and reach 1.4 in the Keiyo manufacturing district.
敬愛大学・千葉敬愛短期大学の論文