Abstract
During the period from Jun., 1983 to May, 1984, dustfall samples with rain water were collected by deposit gauge method at 14 sampling sites in Nara Prefecture and the amount of depositsof ten dissolved components (H+, SO42-, NO3-, Cl-, F-, Na+, K+, Ca2+, Mg2+, NH4+) were measured. And the principal component analysis [PCA] were carried out with respect to these amount of deposits.
As to the pH of samples and the amount of deposits of dissolved components distinguished by population density, the pH was liable to decrease with increasing the population density and the amount of deposits of SO42-, NO3- and NH4+ regarded to be the pollutants originated from human work was liable to increase with increasing the population density. On the other hand, the amount of deposits of Na+, K+, Ca2+, Mg2+, NH4+ and Cl regarded to be the pollutants originated from natural generation was almost constant to variation of population density.
As a result of PCA, the amount of deposits of dissolved components was able to characterized with two principal components (z1, z2). The first principal component z1 was considered to be a factor indicating the degree of synthetic amount of deposits and the second principal component z2 was a factor indicating the contribution of origins of dissolved components. The degree of synthetic amount of deposits and the contribution of origins of dissolved components of monthly and locational distinction was possible to evaluate by the use of these two principal components of z1 and z2.
