Abstract
The contributions of non-sea-salt sulfate and nitrate with an origin of the Asian Continent to the concentrations in acid rain in Toyama City were evaluated from the observational data from 1994 to 2003. The non-sea-salt sulfate and nitrate concentrations in winter precipitation in Toyama City ranged from 43.4 to 71.4 μeq/l with a mean value of 60.5 μeq/l and from 14.6 to 26.7 μeq/l with a mean value of 21.7 μeq/l, respectively. The estimated concentrations of non-sea-salt sulfate with an origin of the Asian Continent ranged from 12.6 to 28.7 μeq/l with a mean value of 20.8 μeq/l, while the estimated concentrations of non-sea-salt sulfate with a domestic origin ranged from 30.5 to 46.9 μeq/l with a mean value of 39.8 μeq/l. The estimated concentrations of nitrate with an origin of the Asian Continent ranged from 2.0 to 4.7 μeq/l with a mean value of 3.4 μeq/l, while the nitrate concentrations with a domestic origin ranged from 11.8 to 21.5 μeq/l with a mean value of 18.3 μeq/l. Contribution ratios of non- sea-salt sulfate and nitrate with an origin of the Asian Continent in winter precipitation in Toyama City seemed to have increased since 1997. This could be attributed to the decrease in the concentrations of non-sea-salt sulfate and nitrate with a domestic origin.
