Study of water-soluble atmospheric humic matter in urban and marine environments

• Published in: Atmospheric research Vol. 87; no. 1; pp. 1 - 12
• Main Authors: Krivácsy, Zoltán, Kiss, Gyula, Ceburnis, Darius, Jennings, Gerard, Maenhaut, Willy, Salma, Imre, Shooter, David
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 2008; Elsevier
• Subjects: Atmospheric concentration; Earth, ocean, space; Exact sciences and technology; External geophysics; Fluorescence; Humic-like substances (HULIS); Meteorology; Molecular weight; Particles and aerosols; Sampling artefact; Sources; UV-VIS absorption; Water-solubility; New Zealand; Europe; Ireland; New Zealand, South I., Christchurch; Eire, Connaught, Galway, Mace Head; Eire; Fluorescence; Water-solubility; Humic-like substances (HULIS); Atmospheric concentration; UV-VIS absorption; Sources; Molecular weight; Sampling artefact; Marine atmosphere; aerosols; Australasia; Artefact; fluorescence spectroscopy; troposphere; Urban atmosphere; Water soluble compound; physicochemical properties; organic materials; Air pollution; chemical composition; Molecular mass; Comparative study; Ultraviolet visible spectrometry
• ISSN: 0169-8095; 1873-2895
• DOI: 10.1016/j.atmosres.2007.04.005

Recently, atmospheric humic matter or humic-like substances (HULIS) have been found in the water-soluble fraction of atmospheric aerosol sampled at different locations. Most of these locations were continental, non-urban sites. Therefore, in this work HULIS was studied in urban and marine environments. The atmospheric concentration varied over a wide range from 0.40 to 5.44 μg m − 3 , from the clean marine air (Mace Head, Ireland) to the heavily polluted winter urban atmosphere (Christchurch, New Zealand). In terms of carbon, ratio of HULIS was 19–51% of water-soluble organic carbon, and 10–22% of total carbon. Different spectroscopic techniques were applied for the physico-chemical characterisation of HULIS including relative aromaticity and molecular weight. Specific absorbance was observed to be much less variable than specific fluorescence, and consequently UV-VIS spectroscopy at λ > 330 nm was recommended for rapid, semi-quantitative determination of HULIS in the water extracts of atmospheric aerosol. Application of a dual filter sampling system at one of the sampling sites has revealed a significant positive sampling artefact which calls for further systematic studies on this subject, and also supports the idea of a secondary organic aerosol formation mechanism of HULIS.