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.