Aerosol chemical characteristics from sampling conducted on the Island of Jeju, Korea during ACE Asia

This paper presents results of an aerosol chemical characterisation experiment conducted on the Island of Jeju, Korea, using a range of techniques for analysing inorganic and organic particle components. Sulphate and ammonium were biased toward the accumulation mode size ranges. Nitrate, sodium, calcium and chloride were found in the larger size ranges and attributed to the collection of modified sea salt and dust particles. In the super-micron aerosol it was apparent that chloride depletion in sea salt had occurred which was mainly by nitrate due to reaction with nitric acid. Similarly, enhanced nitrate was found on the dust aerosol. Results derived from an aerodyne aerosol mass spectrometer (AMS) showed that sub-micron component distributions were consistent throughout the entire campaign, a lack of sub-100nm mass loadings substantiating the notion of an aged sub-micron aerosol population. Sulphate and organic constituents were the dominant mass contributors in this size range. Various aerosol characteristics were dependent on the air mass history, the relative dominance of sulphate and organic mass loadings in the sub-micron aerosol being particularly sensitive to different air types. Loadings of organic components analysed by the AMS were found to increase significantly during direct influence from Korea. Comparison between organic components analysed by the AMS, water-soluble organic carbon (WSOC) derived from impactor sampling and organic carbon derived from a low volume sampler suggested that the volatile components analysed by the AMS were not only water soluble, but also representative of the total organic carbon present. Analysis of mass closure on impactor substrates suggested that the accumulation mode aerosol mass (200-500 nm) could be accounted for by the analysed inorganic components and WSOC. This was not found in larger size ranges, which is expected given the influence of dust and other possible non-refractory primary emissions on the measurement site. (C) 2004 Elsevier Ltd. All rights reserved.