56 CL No. B. Collection Period (eed) DPM sr90/106f+3 773-P 77k-P April. 4-5, 1955 April 11-12, 1955 1.32 1.93 8 +h 775=P April 18-19, 1955 2.27 85 + 6 T16-P April 25-26, 1955 1.82 22.5 + lel 777=P 778=P May 23, 1955 May 10-11, 1955 1.34 1.5) 709 + 52 265 + 12 779-P May 17-18, 1955 1.37 478 + 16 780-P May 2h-25, 1955 1.69 755 + 33 917-P June 16-17, 1955 1.43 710 + 40 918-P August 5-8, 1955 3.0 300 + 20 919-P August 12-16, 1955 4.51 ug +h 920=P August 19-22, 1955 3.5 12h + 6 921-P August 26-29, 1955 3.6 226 + 16 922—P September 26-27, 1955 1.53 158 + 9 923-P September 29-30, 1955 1.69: 12h + 8 71.5 + 303 SrSurface Air Concentration, Foreign Locations There is considerable uncertainty in the air volumes of samples collected at Kodiak, TeAe, Port Lyautey, F.M., and Yokosuka, Japan because the flow rate is not directly recorded, For the earliest reports of air filter data for these three locations, the rated flow rate times the total collection period was taken as the collected air volume. Because the flow rate falls off substantially as dust accumulates on the filter, those samples were overestimated in volume and thus the reported air concentration data were too low, It is considered that a better estimate of their air volum is provided by the average Washington, D. C. volumes for equivalent collection periods. On this basis, the relative air concentration data should be considerably improved, although their absolute value may be in error by as much as 50% or so. All the earlier reported air filter data for Kodiak, Port Lyautey and Yokosuka have been estimated on this basis, and the new results are presen-= ted below,