Takafumi Sugita

Large‐scale transport of pollution aerosol over the east coast of Asia

Eastern Asia contains many large pollution sources whose emissions can be transported over large areas of North Pacific. In order to characterize this transport, we collected a sixty-day series of daily aerosol samples concurrently from Sapporo, Japan and Vladivostok, CIS from April to May, 1991. These were analyzed for non-sea-salt (nss) sulfate and nitrate. The arithmetic mean concentrations of nss-sulfate (4.66 ± 2.68 μg m−3) and nitrate (2.58 ± 1.62 μg m−3) in Vladivostok were 70% and 40% higher than the corresponding concentrations of nss-sulfate (2.69 ± 2.06 μg m−3) and nitrate (1.86 ± 1.42 μg m−3) in Sapporo. Several episodic peaks of nss-sulfate and nitrate in Vladivostok corresponded to the peaks observed in Sapporo, which is located approximately 700 km east of Vladivostok. About 40% and 25% of the variance in the nss-sulfate and nitrate concentrations at the two sites could be explained by the large-scale transport of substances under the strong winds from the west and southwest This suggests that the high concentrations are associated with strong regional sources located to windward of these cities and that the concentrations that we measured are probably representative of a large area of the coastal western North Pacific Ocean.