Studies on the levels in atmospheric concentrations of mercury in Japan

Several factors that influence the total mercury levels in atmosphere concentrations of mercury in Japan were investigated. The daily variation in the mercury content of air was ascribed to daily temperature differences. The maximum amount of mercury in air was found at about 1:00 pm; much smaller amounts were found in the morning and in the evening. The minimum amount of mercury in air was found at about midnight. The effect of atmospheric pressure was less obvious. The seasonal variation indicated that the mercury concentration showed no apparent trend for samples collected in daytime on clear days with no precipitation. The total mercury concentration in the summer as a whole, however, was slightly higher than that of the winter. In addition, the total mercury levels in air have been monitored over a period of 17-years (1978-1994) at three different environmental stations. In 1988, the total mercury in air was minimum levels at three stations and was corresponded to background levels, then they began to rise steadily up to date. It is found that the current atmospheric concentrations of total mercury inferred from measurements of air has an increasing tendency every year.