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Summary and entire article are available on microfiche. Order from American Geophysical Union, 1909 K Street, N. W., Washington, D. C. 20006. Document J76‐004; $1.00. Payment must accompany order. A series of laboratory experiments using natural seawater were conducted to examine several factors which influence the organic carbon(OC) content of marine atmospheric sea‐salt particles produced by bursting bubbles at the air‐sea interface. The organic carbon/Na ratio of these laboratory‐generated atmospheric sea‐salt particles was found to be dependent on the quantity of organic carbon in the seawater, the nature of the organic compounds in the seawater, the amount of surfactants in the seawater, and the distance the bubbles traveled in seawater before bursting at the air‐seawater interface. The dissolved and/or colloidal fractions of the organic material in the seawater used were primarily responsible for the organic carbon content of the atmospheric particles. Filtration of the seawater did not affect the OC/Na ratio of the aerosols produced. The OC/Na ratio of atmospheric sea‐salt particles generated from Sargasso seawater was 0.008±0.005, while that of particles generated from Narragansett Bay water was 0.093±0.053.

Organic carbon (OC) was determined in atmospheric particulate matter collected at several remote marine locations in the northern and southern hemispheres (Bermuda, Hawaii, Samoa). The OC concentrations were rather similar at all three locations, generally ranging from 0.2 to 0.4 µg/m³ STP. The major mass of the OC at all three locations was found on the smallest particles (radii less than 0.5 µm). However, the major mass of OC on laboratory generated atmospheric sea salt particles was found on particles with radii from 1‐3 µm, the same size as the major mass of the sea salt in both the laboratory experiments and in ambient marine air. This suggests that most of the organic material in marine atmospheric particulate matter is not associated with sea salt. Gas‐particle interactions involving organic compounds could explain the observed size distribution of the OC‐containing particles and the rather constant concentrations of organic carbon found in marine atmospheric particulate matter at the locations studied.

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