Samples of organic aerosol were collected in Santiago de Chile. An activated-charcoal diffusion denuder was used to strip out organic vapors prior to particle collection. Both polynuclear aromatic hydrocarbons (PAHs) and aliphatic hydrocarbons were determined using gas chromatography/mass spectrometry (GC/MS). Organic particle sources were resolved using both concentration diagnostic ratios and multivariate methods such as hierarchical cluster analysis (HCA) and factor analysis (FA). Four factors were identified based on the loadings of PAHs and n-alkanes and were attributed to the following sources: (1) high-temperature combustion of fuels; (2) fugitive emissions from oil residues; (3) biogenic sources; and (4) unburned fuels. Multilinear regression (MLR) analysis was used to determine emission profiles and contributions of the sources. The reconstructed concentrations of particle phase aliphatic and polynuclear aromatic hydrocarbons were in good agreement (R2 > 0.70) with those measured in Santiago de Chile.
In a Eucalyptus forest in Portugal were investigated (a)
the formation of secondary organic aerosol formed through
the condensation of low vapor pressure products of
monoterpenes (α- and β-pinene) photooxidation and (b)
the chemical structure of these products related to their
ability to form new particles. Two isomers of pinonic acid
(cis- and trans-2,2-dimethyl-3-acetylcyclobutylethanoic
acid) and norpinonic acid (cis- and trans-2,2-dimethyl-3-acetylcyclobutylmethanoic acid), pinic acid (cis-2,2-dimethyl-3-carboxycyclobutylethanoic acid), pinonaldehyde (2,2-dimethyl-3-acetylcyclobutylethanal), and nopinone (6,6-dimethylbicyclo[3.1.1]heptan-2-one) were detected in all
forest aerosol samples. By considering the diurnal
concentration pattern of the acidic products and Aitken
nuclei observed during the same periods, our results indicated
that cis- and trans-pinonic, cis- and trans- norpinonic
and pinic acids are photooxidation products of α-pinene
chemically coupled with new particles formed. Lipids such
as n-alkanes, n-alkanols, n-alkanals, and n-alkanoic
acids determined in the forest aerosol were associated
with primary biogenic emissions from Eucalyptus trees.
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