devices to determine particle size distribution and radioactivity, and micrometeorological techniques to determine aerosol fluxes. simultaneous experiments were conducted: Four (1) a characterization of the normal (background) suspended aerosols and the contributions from sea spray off the windward beach leeward across the island, (2) a study of resuspension of radionuclides from a field purposely laid bare by bulldozers as a worst-case candition, (3) a study of resuspension of radioactive particles by vehicular and foot traffic, and (4) a study of personal inhalation exposure using small dosimeters carried by volunteers during their daily routines. Less complete studies similar to (1) and (2) had been performed previously on Enjebi (Janet) and background studies similar to (1) were performed later on Eneu. The “normal or background" mass loading measured by gravimetric methods for both atolls is approximately 55 we/m3, The Bikini experiments show that 34,¢/m? of this total is due to sea-salt which is present across the entire island as a result of ocean, reef, and wind actions. The mass loading due to terrestrial origins is therefore about 2lie/m>. The highest terrestria! mass loading observed was 136.2/n immediately after bulldozing. Concentrations o £ 23942405, have been determined for collected aerosols for normal ground cover and conditions, i.e. ‘normal conditions'', in coconut groves, for arezs being cleared by bulldozers and being tilled, i.e. "high activity conditions," and for stabilized bare soil, i.e., the cleared areas after a few days weathering. The plutonium concentration in the collected aerosols changes relative to the plutonium surface soil concentration for the various situations. es TREE, We