Particulate size distributed organic: Compounds in a forest atmosphere

Atmospheric aerosol particles were collected in an Abies boressi forest in central Greece using a high volume cascade impactor sampler. Filters were treated with a solvent, and the organic extract was separated into different fractions by using column chromatography on silica gel. The resulting five organic classes of increasing polarity were analyzed by gas chromatography-mass spectrometry. The particulate matter contained mainly acids, aliphatic components, and minor levels of alcohols, aldehydes, ketones, and aromatic compounds. Samples showed higher concentrations of material in the submicrometer size range. The mass distribution of compounds presented a mode for diameters < 0.49 <mu>m, confirming the secondary origin of aerosol products formed by nucleation/condensation mechanisms from gaseous precursors. Another mode was present for compounds in particles with diameters between 1 and 3 mum as a result of condensation on the surface of the preexisting particles or of mechanical processes.