We discussed the chemical features of major constituents i n precipitation collected in winter (Jan. and Feb. ) from April 1991 to March 1994 along the Sea of Japan on Honshu Island (mainland Japan) using a filtrating bulk sampler in cooperation with the Environmental Laboratories Association. In winter, the area along the Sea of Japan receives more precipitation than other areas and the pH is somewhat lower. Large amount of sea salt is deposited due to the northwestern winter monsoon. In spite of large precipitation amount, nss-SO
42- concentration in the precipitation was nearly equivalent to the average throughout Japan. As the NO
3- concentration was less than the average, nss-SO
42- contributes to acidification of the precipitation more than NO
3- Alkaline components, such as nss-Ca
2 and NH
4+, are lower than the average, especially nss-Ca
2+ being only 0.54 times the average, and which meant that more hydrogen ions were left than in the case of the other areas. The precipitation amount is 1.9times the average and thus the deposition of all components, except Ca
2+ and nss-Ca
2+, is highest along the coast of the Sea of Japan. But, the features of the precipitation of western San-in which locate most western part of the area along the Sea of Japan was somewhat different from the other, which was similar to the feature of nothern Kyushu.
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