Four years' observations of terrestrial lipid class compounds in marine aerosols from the western North Pacific

Abstract

In order to understand the long-range atmospheric transport of terrestrial organic matter over the open ocean, marine aerosol samples were collected on a biweekly basis from 1990 to 1993 in a remote island, Chichi-Jima, in the western North Pacific. The samples were analyzed for lipid class compounds using a capillary gas chromatography (GC) and GC/mass spectrometry (GC/MS). A homologous series of n-alkanes (C20-C40), alcohols (C13-C34 , fatty acids (C9-C34) and α,ω-dicarboxylic acids (C7-C28) were detected in the aerosol samples. Distributions of n-alkanes (0.17-14 ngm-3, average 1.7 ngm-3) are characterized by a strong odd-carbon number predominance (CPI ratios, average 4.5) with a maximum at C29 or C31, indicating that n-alkanes are mainly derived from terrestrial higher plant waxes. Fatty alcohols (0.19-23 ngm-3, average 2.0 ngm-3) show an even-carbon number predominance with a maximum generally at C26 or C28, again indicating a contribution from terrestrial higher plants. On the other hand, fatty acids (2.5-38 ngm-3, average 14 ngm-3) show a bimodal distribution with two maxima at C16 and C24 or C28. Lower molecular weight fatty acids (generally