Seasonal distribution of polar organic compounds in the urban atmosphere of two large cities from the North and South of Europe

Compositions and sources of organic acids in fine particles (PM2.5) over the Pearl River Delta region, south China

“…Higher molecular weight fatty acids ( C 20 ) (HFAs) are derived from terrestrial higher plant wax (Oliveira et al, 2007;Simoneit, 1986), while lower molecular weight fatty acids ( C 20 ) (LFAs) are derived from microbes and marine phytoplankton (Kawamura et al, 2003) and from anthropogenic sources, such as the fossil fuels combustion , biomass burning and cooking (He et al, 2004;Zhao et al, 2007aZhao et al, , 2007b. Higher concentrations of HFAs at the rural site KD suggested more contribution of terrestrial higher plant wax than other sites.…”

“…fatty acids), are important atmospheric oxygenated organic aerosols in PM 2.5 Wang et al, 2006). These acids are either directly emitted from various natural and anthropogenic sources (Ho et al, 2010;Oliveira et al, 2007) or secondarily formed from oxidation of gas-phase precursors followed by gas/particle partition (Wang et al, 2012a). Organic acids are involved in a series of atmospheric chemical reactions occurring in the gas, water and particle phases (Chebbi and Carlier, 1996); they can reduce the surface tension of particles to form cloud condensation nuclei (Facchini et al, 1999), and laboratory experiments also indicate that nucleation of sulfuric acid is considerably enhanced in the presence of organic acids like aromatic acids .…”

Characterisation of solvent extractable organic constituents in atmospheric particulate matter: an overview

“…The increase in concentrations during winter could also be related to the fact that lower winter temperatures promote the decrease of mixing heights and the existence of inversion layers, leading to poorer dispersion and diminishing the dilution factors and, therefore, conducting to an increase of atmospheric pollutant concentrations. On the other hand, as some compounds have a highly temperature dependent gas/particle partitioning coefficient, the high summer temperature could promote their displacement from particulate to gas phase, decreasing their aerosol phase concentrations (Oliveira et al 2007a). In China, concentrations of the homologous organic classes are generally 1-3 orders of magnitude higher than in developed countries (Wang et al 2006b).…”

An enhanced procedure for measuring organic acids and methyl esters in PM<sub>2.5</sub>

“…The di-C 4 -C 5 DCAs (succinic, glutaric, and 3-methylpentanedioic acids) were strongly correlated with phthalic, 4-methylphthalic, benzene-1,2,4-tricarboxylic acids, and 1,8-naphthalic anhydride, and the newly identified 9-oxo-9H-fluorene-1-carboxylic and 2-naphthoic acids. Previous studies have suggested that C 4 -C 5 DCAs are mainly secondary products of volatile organic compound precursors (Kawamura and Kaplan, 1987;Kawamura and Kasukabe, 1996;Graham et al, 2002;Claeys, et al, 2004;Ervens et al, 2004;Gelencsér, 2004;Kanakidou et al, 2005;Kawamura and Yasui, 2005;Oliveira et al, 2007). Phthalic acid has been proposed as a surrogate for the contribution of secondary organic aerosols (Fine et al, 2002;Ho et al, 2010), since it mainly derives from the oxidation of PAHs (e.g., naphthalene) or phthalates in vehicular exhaust and biomass burning (Guillard et al, 1993;Kawamura and Ikushima, 1993;Kawamura and Kaplan, 1987;Kawamura and Yasui, 2005).…”

“…For GC-MS, organic acids need to be derivatized to more volatile esters with BF 3 -methanol, BF 3 -butanol, or N,O-bis-(trimethylsilyl)trifluoroacetamide (Kawamura and Kaplan, 1987;Kawamura, 1993;Fu et al, 2009). The butyl and trimethylsilyl (TMS) derivatives are often used for lowmolecular-weight organic acids, including C 2 -C 10 DCAs, C 2 -C 9 ketocarboxylic acids (Boucharat et al, 1998;Limbeck and Puxbaum, 1999;Nolte et al, 2002;Wang et al, 2006;Oliveira et al, 2007). The methyl esters of C 8 -C 32 monocarboxylic acids and AMAs are more volatile and convenient for GC analysis than butyl and TMS esters (Kawamura and Gagosian, 1987a, b;Plewka et al, 2003;Fraser et al, 2003).…”