이어도 해양과학기지에서 관측된 PM2.5 농도와 이온조성

Abstract

The Objective of this study is to examine the characteristic of fine aerosol (PM2.5) obtained at Ieodo Ocean Research Station, which lies between the eastern part of China and the south western part of Korea. The average mass concentration of PM2.5 was 21.5±17.0 μg/m³ during June 2004~June 2006. The concentration was the highest in winter (34.8 μg/m³) and lowest in summer (16.5 μg/m³). Water soluble ions were measured for samples collected from December 2004 to September 2005. Among them, SO₄²- and NH⁴+ were the most abundant species and accounted for 32.2% and 14.2% of the PM2.5 mass, respectively. The mass fraction of SO₄²- was higher in winter (42%) than in spring (26%). Nitrate concentrations were much lower than those of sulfate due mainly to evaporation during sampling period. The cluster analysis of backward airmass trajectories showed that the high mass loadings (26.9μg/m³ on average) were associated with air originating inland China. Also, the seasonal variation of PM2.5 mass was well correlated with the frequency of westerly winds passing through the western part of China. During the ABC-EAREX2005 (March 2005), PM2.5 mass and major ionic concentrations were higher at Ieodo, compared with PM2.5 measurements at Gosan while they were similar in variation pattern. These results suggested that PM2.5 mass and its ionic composition of Ieodo Ocean Research Station were greatly influenced by continental outflows from China.