Characteristics of aerosol observed during two severe haze events over Korea in June and October 2004

Satellite, ground-based sunphotometer, and real-time carbon particle analyzer data were analyzed to evaluate the causes for two severer haze events observed during 9–12 June and 5–8 October 2004 in Korea. The first event was clearly affected by long-range transported smoke from a multitude of fires in East China. Very high aerosol optical thickness (AOT) levels over 2.0 and elevated surface PM10 concentrations up to 256 μg m−3 were observed during the first haze event. Still very high PM10 mass loadings were observed during the second haze event compared to the first haze event ones with different source characteristics. Due to different origin and pathway of the haze plume, wide difference in the organic/elemental carbon ratio was measured between the two events. It is believed that the aerosol in the first event was dominated by the carbon particles from burning areas in East China while that in the second event was dominated by primary carbon particles from the pollution from large urban areas in China.