Chemical characterisation of marine aerosol at Amsterdam Island during the austral summer of 2006–2007

• Published in: Journal of Aerosol Science
• Main Authors: Claeys, Magda, Wang, Wan, Vermeylen, Reinhilde, Kourtchev, Ivan, Chi, Xuguang, Farhat, Yasmeen, Surratt, Jason D., Gómez-González, Yadian, Sciare, Jean, Maenhaut, Willy
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Elsevier 2010
• Subjects: Austral; Indian; Amsterdam Island
• Online Access: https://authors.library.caltech.edu/17743/; https://resolver.caltech.edu/CaltechAUTHORS:20100316-081308970

Atmospheric aerosols were collected in separate fine (<2.5 μm) and coarse (>2.5 μm) size fractions in the period December 2006–March 2007 at Amsterdam Island in the southern Indian Ocean. A major objective of the study was to assess biogenic impact on the marine aerosol. The samples were analysed for organic carbon, water-soluble organic carbon, major inorganic ionic species, and organic species, including methanesulphonate (MSA), dicarboxylic acids, and organosulphates. The concentrations of sea salt, non-sea-salt sulphate, and water-soluble and water-insoluble organic matter (WSOM and WIOM) were estimated. Sea salt dominated the composition of the aerosol and accounted for 83% and 91% of the sum of the mass of the four aerosol types in the fine and coarse size fractions, respectively. WSOM, which can serve as a proxy for biogenic secondary organic aerosol (SOA), accounted for only 2.8% of the sum of the mass of the four aerosol types in the fine size fraction. MSA was the dominating organic compound with a median concentration of 47 ng m^(−3). The organosulphates were characterised as sulphate esters of hydroxyl acids and a dihydroxylaldehyde, which may originate from the oxidation of algal/bacterial unsaturated fatty acid residues. No evidence was found for isoprene SOA.