Concentrations of Atmospheric Sulfur Compounds in an Extremely Snowy Region, the Hokuriku District, Japan
It is well documented that a more elevated wet sulfate deposition and a more decreased pH are observed in winter than in summer in the part of the Hokuriku District that faces the Japan Sea. This is believed to be due to the extremely high volume of snowfall that contains a high concentration of sulfate. Because the typical pattern of air pressure in winter, i.e., high in the west and low in the east, causes northwestern wind over Japan, which brings much snowfall to the district, it is likely that the air that travels across the Japan Sea contains the causal substances of a high concentration of sulfate in snow. There is evidence of long-range transportation of air pollutants from the Asian Continent. Kitamura et al. investigated the sulfur isotope ratio in snow deposited in this district to conclude that the sulfate was transported from the northern part of the Chang Jiang River. Mukai et al. found that lead isotope ratios in snow samples collected in Japan were similar to those of the leads yielded in Russia and China.