SEASONAL-VARIATION OF AEROSOL COMPOSITION AT CHEJU ISLAND, KOREA

A preliminary assessment of the seasonal variation in chemical composi tion of aerosols measured at Cheju Island, Korea, is presented. Weekly and monthly averaged aerosol composition derived from 15 months of da ily filter measurements are presented. The annual-average non-sea-salt sulfate and nitrate mass concentrations of aerosols measured at Cheju are found to be 6.9 mu g m(-3) and 1.2 mu g m(-3), respectively; calc ium and potassium are present in nearly equal quantities at similar to 0.5 mu g m(-3), and ammonium averaged 1.4 mu g m(-3). Each species is found to follow a seasonal cycle with sulfate, nitrate, ammonium, pot assium and calcium all showing up to 50% higher values in the spring. In contrast, chlorine is 30% lower in the spring. Aerosol enrichment f actors relative to the composition of seawater and crustal material fr om the Gobi dust-source region in China are also presented. The aeroso l measured at Cheju is found to be enriched in sulfate, nitrate and am monium, but deficient in chlorine (relative to seawater). These result s along with modeling studies suggest that the dust surfaces play an i mportant role in nitrate and sulfate formation. Copyright (C) 1996 Els evier Science Ltd