Fatty acids in the marine atmosphere: Factors governing their concentrations and evaluation of organic films on sea‐salt particles

Abstract

[1] Fatty acids (C 14 -C 32 ) in the marine boundary layer were measured in aerosols that were collected over the northern North Pacific from October 1996 to June 1997. Concentrations of lower molecular weight (C 14 -C 19 ) saturated fatty acids (LFAs, 0.8-24 ng m À3 ) showed a positive correlation with sea-salt concentrations, suggesting that LFAs are released from the ocean surface to the atmosphere with sea-salt particles. The averaged ratios of [LFAs] , respectively. The results indicate the seasonal variation of the sea-to-air flux of LFAs relative to that of sea salt with a maximum in spring to summer. The enhanced LFA flux was consistent with the satellite images of chlorophyll a over the northern North Pacific, which showed high biological productivity from spring to summer. On the basis of the ratios of [LFAs] air /[sea salt], relative humidity, and modeled size distribution of sea-salt particles, the coverage of LFAs on sea-salt particles was estimated to range from 0.3 to 14%. This study suggests that the coverage of fatty acids, together with other film-forming materials, may have a significant effect on the physicochemical properties of aerosols, which may be affected by the high biological productivity in the high latitudinal ocean.

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

“…[1][2][3][4][5][6][7][8][9][10][11] Naturally occurring, surface-active fatty acids are common components of the organic fraction. [12][13][14][15] Biological material at the sea surface, including fatty acids and unsaturated organics such as chlorophyll, may be incorporated into marine aerosols via bubble bursting. Little is known about the physical state of internally mixed aerosols, although inorganic aerosols with organic coatings have been observed, [4][5][6][7]11 as well as organic particles with inorganic inclusions 7 and gellike mixtures.…”

UV Photodissociation Spectroscopy of Oxidized Undecylenic Acid Films

“…Although ω-oxocarboxylic (alkene-terminated) acids, such as undecylenic acid, are rarely found in ambient aerosol particles, 60 larger unsaturated fatty acids and their oxidation products are quite common in organic particulate matter. 21,[60][61][62] Oxidation of unsaturated fatty acids by ozone has been studied by many researchers. 40,42,44,[63][64][65][66][67][68] Related reactions of ozone with ordered Langmuir films of phospholipids on water 45,46,69 or with unsaturated SAM (self-assembled monolayers) 39,41,[70][71][72][73] have also been examined.…”

A simple representation of surface active organic aerosol in cloud droplet formation

“…Presence of surface active molecules (surfactants) has been demonstrated in bulk samples of atmospheric cloud and fog waters (Facchini et al, 1999(Facchini et al, , 2000, as well as in aerosol samples (Yassaa et al, 2001;Mochida et al, 2003;Cheng et al, 2004) and aqueous extracts thereof (Oros and Simoneit, 2000;Mochida et al, 2002;Kiss et al, 2005;Dinar et al, 2006;Asa-Awuku et al, 2008) from marine, and rural and urban/polluted continental environments. A number of the identified surface active organic molecules have been observed in laboratory experiments to be CCN active at atmospheric conditions and surface activity can significantly affect the CCN properties of these compounds (Prisle et al, 2010(Prisle et al, , 2008.…”