Annual Fluctuation of pH of Total Deposition with a Dust Jar Sampler

—Annual Variations of pH and Calcium Concetration of Soluble Fraction—

Abstract

Annual fluctuations of pH and ion concentrations of soluble fraction in total deposition with a dust jar sampler were investigated during eight years (1984-1992) in Sendai city. The following results were acquired.
1) The acidification of soluble fraction in total deposition was observed at about 0.085 of pH in every year.
2) The soluble fraction between spring and summer was revealed to be slightly low pH in the comparison between autumn and winter.
3) As the results of factor analysis for pH and ion concentrations, the first factors were pH and Ca²⁺, the second one were Cl^- and Na⁺, and the third one was SO₄^2-.
4) It was suggested that the reason of reduce for calcium concentration of soluble fraction might be the decrease of road dust caused by the car with studded tire which was restricted to use recently. The annual fluctuation of calcium concentration were great enough to affect pH.