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 t reated 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, aliphati c components, and minor levels of alcohols, aldehydes, ketones, and aromati c compounds. Samples showed higher concentrations of material in the submic rometer size range. The mass distribution of compounds presented a mode for diameters < 0.49 <mu>m, confirming the secondary origin of aerosol product s formed by nucleation/condensation mechanisms from gaseous precursors. Ano ther mode was present for compounds in particles with diameters between 1 a nd 3 mum as a result of condensation on the surface of the preexisting part icles or of mechanical processes.