Identification, abundance and origin of atmospheric organic particulate matter in a Portuguese rural area

Respirable suspended particles high-volume samples were collected from a co astal-rural site in the centre of Portugal in August 1997 and their solvent -extractable organic compounds were subjected to characterisation by gas ch romatography-mass spectrometry. Particles were also analysed by a thermal/o ptical technique in order to determine their black and organic carbon conte nt. The total lipid extract yields ranged from 20 to 63 mu gm(-3), containi ng mainly aliphatic hydrocarbons such as n-alkanes, acids, alcohols, aldehy des, ketones and polycyclic aromatic hydrocarbons. The higher input of vasc ular plant wax components was demonstrated by the distribution patterns of the n-alkanes, n-alkanoic acids and n-alkanols homologous series, with C-ma x at C-29, C-22/C-24 and C-30, respectively. The CPI values for these serie s were in the range 1.8-9.7, being indicative of recent biogenic input from microbial lipid residues and flora epicuticular components. Specific natur al constituents (e.g, phytosterols, terpenes, etc.) were identified as mole cular markers. Some oxidation products from volatile organic precursors wer e also present in the aerosols. In addition, all samples had a component of petroleum hydrocarbons representing urban and vehicular emissions probably transported from the nearest cities and from the motorway in the vicinity. This data set could be used to make a mass balance with organic carbon, or ganic extracts and elutable matter, permitting also the comparison with lip id signatures observed for other regions. (C) 2001 Elsevier Science Ltd. Al l rights reserved.