with "small" particles arising from upwind. Consequently, the combined sample of "small" particles would have an average wCi/g value caused by particle dilution from two sources. In order to direct attention to a possible relationship between plutonium-239 and americium-241 resuspension, a cross comparison of data from Fig. 3 and Fig. 4 is shown in Fig. 5. In this case, the yCi/g for plutonium-239 on “large” particles is shown along with the uCi/g for americium-241 on "small" particles. In both cases, the uCi/g was constant between 1.9- and 15-m sampling heights. For greater heights, the uCi/g increased for both plutonium-239 on "large" particles and americium-241 on "small" particles. This increase was greater for americium-241 on "small" particles than for plutonium~239 on "large" particles. Nevertheless, for both plutonium-239 on "large" particles and americium-241 on "small" particles, the wCi/g decreased rapidly between sampling heights of 91 m and 122 m. It is unknown why there appears to be a relationship between americium-241 transport on "small" particles at elevated heights as compared to plutonium-239 transport on "large" particles at elevated heights. There are at least three possible explanations for this relationship. The ameri- cium-241 and plutonium-239 were originally deposited at the resuspension source in two different size ranges. A second possibility is that plutonium-239 attaches to soil particles more readily than americium-241. The third possibility is there may be some mechanisms by which americium' 241 is released from plutonium~239-241 resuspension sources. Possibly for an aged plutonium resuspension source, sufficient daughter americium-241 has grown in by decay of plutonium-241. During decay, small americium-241 particles could be ejected from the parent plutonium. After ejection, the americium-241 small particles no longer retain their identity with the parent plutonium which may be attached to large particles. Thus, in being resuspended, americium-241 is in a small particle diameter range as compared to the parent plutonium on large particles. Additional plutonium-239 and americium-241 data concerning transport on both large and small soil particles are needed in order to clarify the physics explaining these compared observations. Average Horizontal Fluxes Average horizontal fluxes in uCi/(m2 day) were calculated for both small and large particles. Average horizontal plutonium-239 fluxes are shown in Fig. 6. For large particles, the maximum flux was at a sampling height of 60 m. at this height. particles. This maximum flux reflects, in part, the larger uCi/g The flux on small particles was less than on large On the right side of the figure is shown the percent of the airborne flux on small particles. The plutonium-239 flux on small particles ranged from 32 to 46% of the total calculated flux. Average horizontal fluxes for americium-241 are shown in Fig. 7. For transport on small particles, the flux was maximum at 5 x 10-7 yCi/ (m2 716