Sources, Occurrence and Analysis of Carboxylic Acids in Atmosphere

Abstract

Carboxylic acids are products of photooxidation of volatile organic compounds or of anthropogenic activities. Formic, acetic and propionic acids are the most abundant monocarboxylic acids while oxalic, malonic and succinic acids are the most widespread dicarboxylic acids. Oxodicarboxylic and tricarboxylic acids were also found in atmosphere. The low-molecular-weight monocarboxylic acids occur mostly in gas phase while di- and higher-carboxylic acids are predominately bound to aerosol particles. Carboxylic acids occur in atmosphere in ppb concentrations. Carboxylic acid vapours were sampled using diffusion denuders or impingers whereas solid acids using filters or impactors. After extraction, acids are analyzed by gas chromatography, liquid chromatography or capillary electrophoresis.