Inorganic and organic speciation of atmospheric aerosols by ion chromatography and aerosol chemical mass closure

• Main Author: Wang, Wan
• Other Authors: Maenhaut, Willy
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Ghent University. Faculty of Sciences 2010
• Subjects: Earth and Environmental Sciences; secondary species; particulate matter; dicarboxylic acids; sampling artifacts; Amsterdam Island
• Online Access: https://biblio.ugent.be/publication/1048356; http://hdl.handle.net/1854/LU-1048356; https://biblio.ugent.be/publication/1048356/file/4335370

This thesis had the following objectives: (1) to measure major and minor inorganic ionic constituents by ion chromatography (IC) in atmospheric aerosol samples; (2) to determine low molecular weight dicarboxylic acids (DCAs) and methanesulphonate (MSA-) by IC and to assess their contribution to the water-soluble organic carbon (WSOC); (3) to perform quality control of the IC data, e.g., by comparing them with total element data; (4) to examine the sampling artifacts for inorganic and organic species on quartz fibre filters; and (5) to perform aerosol chemical mass closure. SO42- and NH4+ were predominantly present in the fine and NO3- in the coarse size fraction at all sites. At most sites there was sufficient fine NH4+ to fully neutralise all fine SO42- and NO3-. The comparison of the IC and total element data for S, K, and Ca for the various sites indicated that the Ca was fully water-soluble and most of the S was SO42-. From the back/front filter ratios for the quartz fibre filter samples it appeared that sampling artifacts were negligible for all inorganic species, except for NO3-. Our back/front filter ratios for the organic species increased in the following order: oxalate (1.5%), succinate (3%), MSA- (4%), malonate (2-9%), glutarate (7-26%). With regard to the four DCAs, oxalate was always the most prevailing. The carbon in the sum of the four DCAs accounted for 3-7% of the WSOC. Aerosol chemical mass closure was performed with the IC data in combination with carbonaceous and element data. Secondary inorganic aerosols were an important contributor to the fine aerosol mass at all sites, with high levels of non-sea-salt-sulphate in summer and of nitrate in winter. Organic matter was another important component in the fine aerosol at urban and forested sites; it accounted for up to 73% of the fine aerosol mass at the forested site of Hyytiälä in Finland. Sea salt was by far the major component in both the fine and coarse aerosol at Amsterdam Island. Crustal matter (from re-suspended road dust) was the ...