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 &mgr;g/m3 STP. The major mass of the OC at all three locations was found on the smallest particles (radii less than 0.5 &mgr;m). However, the major mass of OC on laboratory generated atmospheric sea salt particles was found on particles with radii from 1--3 &mgr;m, 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.