Measurements of the surface aerosol were performed by means of two laser optical particle counters during the East Greenland Sea Marginal Ice Zone Experiment. The number size distributions and total concentrations obtained for particles with radii between 0.09 μm and 12.5 μm were close to the global background level. Number size distributions decreased by a fraction of 100 with a frontal passage for particles with radii greater than 0.9 μm, while the size distribution for smaller particles remained fairly constant. The size distributions for wind speeds above and below the threshold for whitecap formation on the sea surface were compared. The number size distributions for particles above 1-μm radius for wind speeds of 5 m s-1 were less by a factor of 100 than those for 7 m s-1. ¿ American Geophysical Union 1987