Multi-Oxygenated Organic Compounds in Fine Particulate Matter Collected in the Western Mediterranean Area

The chemical characterization of aerosols, especially fine organic fraction, is a relevant atmospheric challenge because their composition highly depends on localization. Herein, we studied the concentration of multi-oxygenated organic compounds in the western Mediterranean area, focusing on sources and the effect of air patterns. The organic aerosol fraction ranged 3-22% of the total organic mass in particulate matter (PM)(2.5). Seventy multi-oxygenated organic pollutants were identified by gas chromatography-mass spectrometry, including n-alkanones, n-alcohols, anhydrosugars, monocarboxylic acids, dicarboxylic acids, and keto-derivatives. The highest concentrations were found for carboxylic acids, such as linoleic acid, tetradecanoic acid and, palmitic acid. Biomarkers for vegetation sources, such as levoglucosan and some fatty acids were detected at most locations. In addition, carboxylic acids from anthropogenic sources-mainly traffic and cooking-have been identified. The results indicate that the organic PM fraction in this region is formed mainly from biogenic pollutants, emitted directly by vegetation, and from the degradation products of anthropogenic and biogenic volatile organic pollutants. Moreover, the chemical profile suggested that this area is interesting for aerosol studies because several processes such as local costal breezes, industrial emissions, and desert intrusions affect fine PM composition.

Automated summary

The study investigated the chemical characteristics of organic aerosols in the western Mediterranean, finding that the organic PM fraction mainly originates from biogenic pollutants emitted directly by vegetation, as well as degradation products of anthropogenic and biogenic volatile organic pollutants. Additionally, carboxylic acids from anthropogenic sources-mainly traffic and cooking-were identified. The region is of interest for aerosol studies due to various processes such as local coastal breezes, industrial emissions, and desert intrusions that affect fine PM composition.