| Research Abstract |
Particulate matter (aerosol) has been collected in the urban atmosphere of Tokyo, and in the remote atmosphere including Mt. Haruna, Gunma Prefecture, and Titijima Island in western North Pacific. Atmospheric fallout samples were also collected in Kawasaki and Fuchu. Various organic compounds were isolated from the samples and were determined by gas chromatography (GC) and GC-mass spectrometry. They include n-alkanes, polynuclear aromatic hydrocarbons, polynuclear aromatic ketones, phthalates, fatty acids, dicarboxylic acids, oxoacids and aldehydes. The results showed that major species in the organic aerosols were low molecular dicarboxylic acids such as oxalic, malonic, and succinic acids. The relative abundance of these polar organic compounds in the aerosol particles increased at around noon time of the day and in the summer of the year, suggesting that they are secondarily produced in the atmosphere by photochemically induced reactions of organic molecular mainly derived from anthropogenic sources. omega-Oxocarboxylic acids (C2-C10) were identified in the samples. Some of the oxoacids (C3 and C4) have been discovered in this study. They are considered as intermediates of photooxidation reactions of hydrocarbons to dicarboxylic acids.
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