5h VIII, Air Concentration Air filter samples provided by Mr. I. H. Blifford, Naval Research Laboratory, Washington, D. C. Collections were made on Army Chemical Corps Type V filters of 200 square inches area and of heavy. asbestos fiber composition, A. Sr” Surface Air Concentration, Yashington, D. C. CLNo. Volume Collection Period (¢t3x10-5) pw sr90/10%s3 20D April 5-8, 1953 hed 18.6 + 0.7 20hA October 2-6, 1953 1.7 41.1 + 3.0 20L,B October 6-9, 1953 36h 30.5 + 1.1 130 October 12-15, 1953 Be 70 + 12 Sly-P April 3-5, 195k 2.92 91+ 7 20hE April 8-10, 195) 2.6 bo + 062 20) April 9-11, 195) 1.7 125+5 20)F April 10-12, 195) 36h 258 + 6 515-P_ April 12-14, 195) 1.95 65.5 + 4.6 20hG April 15-17, 195) 307 11.0 * 0.5 20KH3 April 17-19, 195) 2,8 2067 + 0.6 Sl6-P apr. 29-May 1, 195h (340 3262 + 266 895-P May 5=7, 195 2033 210 + 12 517-P May 11-13, 1954 2.76 31.3 + 2.2 896-P May 17-19, 195) 2.59 120 + 7 518-P May 2-26, 195) 2.61 216 + 12 897-P _May 28-30, 195) 519-P June 1-3, 195k 3.80 133 + 7 2.90 68.3 + bel 898~P June 14-17, 195h 45 79 + 6 899—P June 23-26, 195 3.79 51 + 3 520-P July 16-17, 195) 1,88 47.0 + 204 521-P July 2-26, 1954 2.56 - 7365 + 542