Chemical Characterization of Fine and Coarse Particles in Gosan, Korea during Springtime Dust Events

Particulate matter was collected at Gosan, Korea, a remote location in the East China Sea, from late-March through May, 2007. Two sizes of particles, fine (PM2.5) and coarse (PM10–2.5) modes, were analyzed for chemical composition. Samples were analyzed by mass, elemental and organic carbon, and inorganic ions. Organic molecular markers were also measured using solvent-extraction gas chromatography mass spectrometry in order to identify different pollution sources. Two major dust events were captured, occurring on 31 March and 26 May, and were characterized by high concentrations of coarse particles, calcium, and secondary inorganic ions. A major pollution event occurred on 26 April with elevated fine particle concentrations and markers of combustion-related and secondary aerosols. Non-event periods in April and May were used to provide context in the interpretation of extreme events. This study demonstrates that carbonaceous aerosols from biomass burning, coal combustion, and motor vehicles containing organic and elemental components that are typically found in fine particles were included in coarse particle mass during dust events. Primary and secondary carbonaceous particles were found to become internally mixed with dust, which is expected to have implications on the dust’s chemical composition and surface properties.