Long-range transport contribution to dry deposition of acid pollutants in South Korea

Long-range transport for dry acidic deposition over South Korea has been estimated using a simplified chemical model and the K-mean clustering technique. The three consecutive daily mean National Center for Environmental Protection reanalyzed 850 hPa geopotential height fields without precipitation on the last day over South Korea are used for clustering of synoptic patterns for the period of 1994–1998. Two emission conditions are simulated for each cluster to estimate long-term impact by long-range transport for acidic dry deposition over South Korea. One condition takes all emissions within the simulated domain into account as a base case and the other condition excludes South Koreaʹs emission and all oxidizers and considering all of the other emissions as a control case. The results of the present study indicate that the contribution of long-range transport to the annual total South Koreaʹs dry deposition of sulfur is found to be about 30% (78 eqha−1 yr−1), of which 65% and 35% are contributed by SO2 and SO42−, respectively, whereas that of total nitrogen deposition is found to be 49% (240 eqha−1 yr−1), of which 80% and 20% are contributed by the transformed nitrogen species including HNO3, NH4+ and NO3−, and the primary pollutants of NOx and NH3, respectively, suggesting the importance of secondary pollutants of nitrogen species for long-range transport to South Koreaʹs total dry deposition of nitrogen.