Seasonal variations of concentrations and optical properties of water soluble HULIS collected in urban environments
Major contributors to the organic aerosol include water-soluble macromolecular compounds (e.g. HULIS WS: Water Soluble Humic LIke Substances). The nature and sources of HULIS WS are still largely unknown. This work is based on a monitoring in six different French cities performed during summer and winter seasons. HULIS WS analysis was performed with a selective method of extraction complemented by carbon quantification. UV spectroscopy was also applied for their chemical characterisation. HULIS WS carbon represent an important contribution to the organic aerosol mass in summer and winter, as it accounts for 12–22% of Organic Carbon and 34–40% of Water Soluble Organic Carbon. We found strong differences in the optical properties (specific absorbance at 250, 272, 280 nm and E2/E3 ratio) and therefore in the chemical structure between HULIS WS from samples of summer- and wintertime. These differences highlight different processes responsible for emissions and formation of HULIS WS according to the season, namely biomass burning in winter, and secondary processes in summer. Specific absorbance can also be considered as a rapid and useful indicator of the origin of HULIS WS in urban environment.
Vorschau
Zitieren
Baduel
Zugriffsstatistik
