In order to estimate ocean-atmosphere mass transfer fluxes controlled by aerosol generation the bubble population at the interface has to be known. This information is usually inferred from measurements at a given depth below the water surface and from broad assumptions about the variation of bubble population with depth. However, recent measurements are not consistent with the usually assumed bubble population variation, and a direct investigation in the immediate vicinity of the interface appears to be necessary. Measurements above the minimum wave trough are difficult because a sensor level is alternately in the air and in the water. We have used a laser-based single-particle technique to investigate this zone for different breaking wave fields generated in a wind-water simulation facility. The main bubble population characteristics, common to the different breaking wave fields investigated, are as follows: a roughly invariant size distribution characterized by a spectrum slope of approximately -2, concentrations rapidly increasing upward, following approximately an exponential law, and clustered distributions at the different measurement levels. These results, consistent with equivalent measurements below the wave trough level, correspond to bubble generation zone characteristics suggested in a previous investigation and provide further evidence of the existence of a universal bubble distribution at the interface of breaking wave fields. Very high bubble concentrations, up to 1010 bubbles of diameter larger than 60 μ per cubic meter (nearly 10,000-fold the value just below the trough level), are observed at the crest levels. ¿American Geophysical Union 1987