5h VIII, Air Concentration Air filter samples provided by Mr, I, H. BUifford, Naval Research Laboratory, ‘“fashinvton, D. C. Collections were made on army Chemical Corps Type V filters of 200 square inches area and of heavy asbestos fiber composition. Aes Sr?0 Surface Air Concentration, ashineton, D. C. CL No. Volune Collection Period (t3x10-$) pet Sr90/10%re3 20D April 5-8, 1953 4.5 18.6 + 0.7 20h October 2-6, 1953 1.7 41.1 + 3.0 20)B October 6-9, 1953 3. 30.5 + lel 130 October 12-15, 1953 3. 70 + 12 Sly-P April 3-5, 1954 2.92 gl +7 20LE ipril 6-10, 195) 2.6 6. + 0.2 204C April 9-11, 195) 1.7 125+ 5 20F April 10-12, 195) 3k 256 + 6 515-P April 12-14, 196h 1.95 65.5 + L.6 20LG April 15:-17, 195) 347 11.0 * 0,5 20H3 foril 17-19, 195) 20d 2067 + 0.6 516-P apr. 29-Hay 1, 195) 3.0 32.2 + 2.6 095=P Nay 5-7, 195k 2.33 210 + 12 517-P Hay 11-13, 1954 2.76 31.3 + 202 896-P May 17-19, 195) 2659 120 + 7 518={P Mav 2h-26, 195) 2,61 216 + 11 897-P May 28-30, 195) 3.80 133 + 7 519-P June 1-3, 1954 2.90 65.3 + hel 890~P June 14-17, 195h 4h5 79 + 6 899=-P June 23-26, 1954 3.79 | 51+ 3 520-P July 16-17, 195) 1.86 47.0 + 2h 521-P July 24-25, 195) 2.56 73.5 + 5.2 . NYO 35