Role of organic and black carbon in the chemical composition of atmospheric aerosol at European background sites

The mass concentrations of inorganic ions, water-soluble organic carbon, water-insoluble organic carbon and black carbon were determined in atmospheric aerosol collected at three European background sites: (i) the Jungfraujoch, Switzerland (high-alpine, PM_2.5 aerosol); (ii) K-puszta, Hungary (rural, PM_1.0 aerosol); (iii) Mace Head, Ireland (marine, total particulate matter). At the Jungfraujoch and K-puszta the contribution of carbonaceous compounds to the aerosol mass was higher than that of inorganic ions by 33% and 94%, respectively. At these continental sites about 60% of the organic carbon was water soluble, 55–75% of the total carbon proved to be refractory and a considerable portion of the water soluble, refractory organic matter was composed of humic-like substances. At Mace Head the mass concentration of organic matter was found to be about twice than that of nonsea-salt ions, 40% of the organic carbon was water soluble and the amount of highly refractory carbon was low. Humic-like substances were not detected but instead low molecular weight carboxylic acids were responsible for about one-fifth of the water-soluble organic mass. These results imply that the influence of carbonaceous compounds on aerosol properties (e.g. hygroscopic, optical) might be significant.     

Background Aerosol Properties in the European Arctic

Background arctic aerosol properties generally observed during the summer were studied at Ny-Ålesund, Svalbard in a six-week campaign where the aerosol size distribution and chemical composition were measured. The results presented here demonstrate the marked difference between the background arctic aerosol composition in comparison to the aged aerosol arriving in the area by long-range transport from southern latitudes. It is found that sulphate is the major water-soluble component of background aerosol followed by sea salt. Aged aerosol arriving in the Arctic from polluted areas is recognised by an increase in black carbon and in the refractory aerosol fraction.