DISCUSSION OF iM@SULTS I, Sr90 Surface iir Concentration Data Larre air blower samples,collected over tine last several vears at tie Naval Research Laboratory, “Iasnineton, D, C. by I, H. Blifford and associates, were made available to us for Sr?0 assav, Collections were made on irmy Chemical Cerne T:-pe V filters of 200 square inches area and of heavy asbestos fiber composition, Collection volumes ranzed from about 1 to S million cubic feet of air for collection neriods of one day to one week, The large blower samples vihieh were analvzed from Sr?0 were collected from four locations: Washinston, , Cog Kodiak, ‘leske; Port Lyautey, French Morocco; and Yokosuka, Janan, 4 summary of the Sr90 concentration data, together .:ith the location, collection veriod and sample volume for each sanple, is presented in the last section of this report, The “fashineton, D. ©. Sr90 air concentration data are presented in Figure 1. For these sarples, the volumes were cemputed from recorded flow rate data. Figure 2 shows the variation in total flot with length of the collection due to dust loedine of filtersat the Tasnin-ton, 0. C. station. This curve was obtained from ifr, Blifford at the Naval Research Laboratory, who indicated quite large variations of individual collection volumes from the average values sho-vm. The data “or the three foreien stations are presented in Figure 3, For these, the collection volumes were not monitored and the volume of each sainple wes estimated b* assuminr the effect of dust loading observedotpshington, B.C. (Figure 2) applied equally well et these other locations. The necessity of makint this essumption imposes a restriction on comparison of relative air concentrations for the Jour locations but dces allov us to consider the change in alr concentration zith time at each location, SS