Organic aerosol molecular composition and gas–particle partitioning coefficients at a Mediterranean site (Corsica)

• Published in: Journal of environmental sciences (China) Vol. 40; pp. 92 - 104
• Main Authors: Rossignol, Stéphanie, Couvidat, Florian, Rio, Caroline, Fable, Sébastien, Grignion, Guillaume, Savelli, Pailly, Olivier, Leoz-Garziandia, Eva, Doussin, Jean-Francois, Chiappini, Laura
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.02.2016; Elsevier
• Subjects: Aerosols - analysis; Aerosols - chemistry; Air Pollutants - analysis; Air Pollutants - chemistry; Bridged Bicyclo Compounds - analysis; Carbonyls; Carboxylic acids; Citrus; Cyclohexenes - analysis; Environmental Monitoring - methods; Environmental Sciences; France; Gas Chromatography-Mass Spectrometry; Gases - analysis; Gases - chemistry; Gas–particle partitioning; Mediterranean area; Mediterranean Region; Monoterpenes - analysis; Oxidation-Reduction; Secondary organic aerosol; Smog - analysis; Terpenes - analysis; Volatile Organic Compounds - analysis; Volatile Organic Compounds - chemistry; Weather; MED; Mediterranean area; Secondary organic aerosol; Carboxylic acids; Gas–particle partitioning; Carbonyls; CARBONYLS; SECONDARY ORGANIC AEROSOL; CARBOXYLIC ACIDS; MEDITERRANEAN AREA; GAS–PARTICLE PARTITIONING
• ISSN: 1001-0742; 1878-7320
• DOI: 10.1016/j.jes.2015.11.017

Molecular speciation of atmospheric organic matter was investigated during a short summer field campaign performed in a citrus fruit field in northern Corsica (June 2011). Aimedat assessing the performance on the field of newly developed analytical protocols, this work focuses on the molecular composition of both gas and particulate phases and provides an insight into partitioning behavior of the semi-volatile oxygenated fraction. Limonene ozonolysis tracers were specifically searched for, according to gas chromatography–mass spectrometry (GC–MS) data previously recorded for smog chamber experiments. A screening of other oxygenated species present in the field atmosphere was also performed. About sixty polar molecules were positively or tentatively identified in gas and/or particle phases. These molecules comprise a wide range of branched and linear, mono and di-carbonyls (C3–C7), mono and di-carboxylic acids (C3–C18), and compounds bearing up to three functionalities. Among these compounds, some can be specifically attributed to limonene oxidation and others can be related to α- or β-pinene oxidation. This provides an original snapshot of the organic matter composition at a Mediterranean site in summer. Furthermore, for compounds identified and quantified in both gaseous and particulate phases, an experimental gas/particle partitioning coefficient was determined. Several volatile products, which are not expected in the particulate phase assuming thermodynamic equilibrium, were nonetheless present in significant concentrations. Hypotheses are proposed to explain these observations, such as the possible aerosol viscosity that could hinder the theoretical equilibrium to be rapidly reached. [Display omitted]