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The 10-day interval basis measurements of precipitation samples at Yangyang, the rural and coastal area on thetemporal variations of major ions September 1991 to February 1997. The precipitation was slightly acidic, and37% of the samples in winter were pH less than 4.5. The concentrations of cations were found on the orderNa± ¤ NH4± ¤ Ca2± ¤ Mg2± ¤ K± and those of anions followed the pattern Cl-¤ SO42-¤ NO3-. Neglecting seasalt components, the major ions controlling precipitation chemistry were nss-SO42- and NO3- in anion and NH4±and nss-Ca2± were higher than those measured in Japan. Most of nss-SO42- and NO3- were neutralized by ammonia and calciumspecies, especially alkaline soil particles in spring and ammonia gas in other seasons. Considering also the annualvalue of [nss-SO42-]/[NO3-] ratio of 2.62 and the neutralizing factors, ammonium sulphate compounds weredominant. Annual mean concentrations of these ions showed relatively small uctuations, while larger seasonalvariations were observed with higher levels in spring and winter. Precipitation amount, inuence extent of acidicgases and alkaline particles long-range transported from China continent, and energy consumption pattern in eachseasonmight be able to explain this seasonal trend.