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 atmosphere 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.