Particle size distribution of lipids in aerosols off the coast of Peru

Abstract

Lipid components in aerosols were characterized as a function of particle size from samples collected in spring 1981 off the coast of Peru as part of the Sea‐Air Exchange Program. The investigation was designed to determine (1) the particle size distributions for different terrestrial and marine source marker organic compounds close to their source, (2) the importance of the atmosphere as an input source to the sea for terrestrial compounds, and (3) the significance of recycling of the terrestrial components of these compound classes from seawater back into the atmosphere. The terrestrially derived components of three compound classes (fatty alcohols, wax esters, and n‐alkanes) were found to have similar particle size distributions. They are relatively evenly distributed over the whole particle size range, suggesting (1) little modification of the wide spectrum of plant‐ and soil‐derived particles by short‐range transport offshore and (2) insignificant gas‐particle partitioning for these materials. On the other hand, the terrestrially derived fatty acid salts show a different particle size distribution probably due to their very different physicochemical properties. The atmospheric flux to the sea surface via both wet and dry deposition is not significant in relation to the flux through the euphotic zone of the water column for two lipids of terrestrial origin, octacosanoic acid and 24‐ethylcholest‐5‐en‐3β‐ol. No significant recycling from the sea surface back into the atmosphere was observed for lipid compounds of terrestrial origin. Marine‐derived sterols, fatty alcohols, and fatty acid salts were found in high concentrations in surface microlayer samples. The enrichment of these compound classes is about 2–4 orders of magnitude relative to bulk seawater.

The effects of the coastal environment on the atmospheric mercury cycle

“…[35] One potential source of underestimation is that sea salt is formed from the very surface layer of the ocean, which is often more concentrated in pollutants than water at depths of several centimeters [Schneider and Gagosian, 1985]. The concentration of the grab sample taken offshore at Pompano Beach was 0.9 ng L À1 , which is similar to that of other Atlantic Ocean samples from various depths Mason and Sullivan, 1999;Lamborg et al, 1999].…”

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

“…However, they are similar to those (0.3 -0.6 ngm À3 ) reported in the marine aerosols from off the coast of Peru [Schneider and Gagosian, 1985]. In contrast, the concentrations are higher than those (0.02-0.16 ngm see Figure 1), Marshal Islands, tropical North Pacific [Gagosian et al, 1982].…”

Liquid–liquid phase separation in particles containing organics mixed with ammonium sulfate, ammonium bisulfate, ammonium nitrate or sodium chloride

“…These particles, which are produced from a bubble bursting mechanism (Woodcock et al, 1953;Blanchard and Woodcock, 1957), can often contain relatively low O : C organics such as sterols, fatty acids and fatty alcohols (Schneider and Gagosian, 1985;Peltzer and Gagosian, 1987;Sicre et al, 1990;Kawamura et al, 2003). Based on the liquid-liquid phase separation results for NaCl containing particles presented here and the O : C of sterols, fatty acids and fatty alcohols (O : C less than approximately 0.5) thought to be present in the marine boundary layer, liquid-liquid phase separation is also expected to be a common occurrence in marine environments.…”