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

Abstract

[1] 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 (C 20 -C 40 ), alcohols (C 13 -C 34 ), fatty acids (C 9 -C 34 ) and a,w-dicarboxylic acids (C 7 -C 28 ) were detected in the aerosol samples. Distributions of n-alkanes (0.17-14 ngm À3, average 1.7 ngm À3 ) are characterized by a strong odd-carbon number predominance (CPI ratios, average 4.5) with a maximum at C 29 or C 31 , indicating that n-alkanes are mainly derived from terrestrial higher plant waxes. Fatty alcohols (0.19-23 ngm À3 , average 2.0 ngm À3 ) show an even-carbon number predominance with a maximum generally at C 26 or C 28 , again indicating a contribution from terrestrial higher plants. On the other hand, fatty acids (2.5-38 ngm À3 , average 14 ngm À3) show a bimodal distribution with two maxima at C 16 and C 24 or C 28 . Lower molecular weight fatty acids (generally <C 20 ) that are mainly derived from marine organisms showed higher concentrations in summer. In contrast, higher molecular weight fatty acids (C 21 -C 34 ) derived from terrestrial higher plants, together with C 25 -C 35 alkanes, C 20 -C 34 alcohols and C 20 -C 28 dicarboxylic acids, generally showed higher concentrations in winter to spring seasons. This seasonal trend is most likely interpreted as atmospheric transport of terrestrial organic matter from Asian continent in winter/spring, when westerly winds dominate over the western North Pacific. Backward trajectory analyses supported the long-range atmospheric transport of higher plant-and soil-derived organic matter from the Asian continent over the Pacific Ocean. This study also suggested that the atmospheric transport is the main pathway for the terrestrial lipid compounds that are abundantly present in the deep-sea sediments in the Central Pacific.

Compositions and sources of organic acids in fine particles (PM2.5) over the Pearl River Delta region, south China

“…Detected 40 organic acids totaled 82.6-756 ng/m 3 with an average value of 280 ng/m 3 , and accounted for 0.66%-3.69% of OC with an av- Saturated fatty acids (C14:0-C32:0) from this study in the PRD region showed a strong even carbon number predominance with a maximum at palmitic acid (C16:0) and stearic acid (C18:0) ( Table 1). This was quite similar to the distribution patterns reported in the urban areas (Fraser et al, 2002;Fu et al, 2010;Ho et al, 2011), but different from the bimodal distribution observed at the mountain site (Fu et al, 2008) or in marine aerosols (Fu et al, 2011;Kawamura et al, 2003) with maximums at C16:0 and C24:0/C28:0. The concentrations of C16:0 and C18:0 in the PRD region averaged 85.8 and 27.8 ng/m 3 , respectively, comparable with those reported in some urban sites, such as Nanjing in China (Wang and Kawamura, 2005) and Chennai in India (Fu et al, 2010).…”

Sugars as source indicators of biogenic organic carbon in aerosols collected above the Howland Experimental Forest, Maine

“…An increase in wax concentrations in aerosol samples affected by wildfire plumes has been observed previously by Abas et al (1995), Conte and Weber (2002) and Kawamura et al (2003).…”

“…Atmospheric particles contain organic tracers that are characteristic of their sources, mode of formation and subsequent alteration during transport downwind (Simoneit, 1977(Simoneit, , 1984(Simoneit, , 1989Marty and Saliot, 1982;Mazurek and Simoneit, 1984;Schauer et al, 1996;Fang et al, 1999;Simoneit et al, 1999;Conte and Weber, 2002;Kawamura et al, 2003;Simoneit et al, 2004a and references therein). Organic matter in aerosol particles is derived from four major sources and is admixed depending on environmental conditions.…”

“…The biogenic biomarkers in atmospheric samples consist of homologous series of nalkanoic acids, n-alkanols and n-alkanes derived from epicuticular waxes and related lipids of higher plants (Simoneit, 1977(Simoneit, , 1978, with lesser amounts of other oxygenated homologous species, such as n-alkanedioic acids and n-alkan-2-ones (Simoneit and Mazurek, 1982;Abas and Simoneit, 1996;Fang et al, 1999;Simoneit, 1989Simoneit, , 1999Conte and Weber, 2002;Kawamura et al, 2003). Other primary biogenic biomarkers observed in atmospheric samples include sterols (cholesterol, campesterol and sitosterol), triterpenoids (e.g., α-and β-amyrone), diterpenoids (e.g., dehydroabietic acid) and sugars (mono-and disaccharides) (Simoneit, 1999;Simoneit et al, 1999;Graham et al, 2002;Simoneit et al, 2004a-c).…”

The Oxidation of Oleate in Submicron Aqueous Salt Aerosols: Evidence of a Surface Process

“…Oleic acid has been detected in urban, rural, and marine aerosols and is used as a marker for meat cooking in continental aerosol. 12,[28][29][30][31][32][33][34][35][36] Several factors have motivated these studies, including: quantifying the time scale for organic aerosol to be converted from hydrophobic to hydrophilic via oxidation thereby influencing their CCN ability, estimating the lifetime of unsaturated organics in aerosol particles, and evaluating organic aerosol oxidation as a potential source of volatile organics. The reaction has been studied using pure oleic acid aerosols, [37][38][39][40][41][42][43][44][45] 2-30 nm thick films on polystyrene beads, 46 ∼1 µm thick films on aqueous sea salt aerosol 47 and on macroscopic films in coated wall flow tube studies.…”