Table 12a——Sr®* SURFACE AIR CONCENTRATION, WASHINGTON, D.C. (Analyses at University of Chicago) Air filter samples provided by 1. H. Blifford, Naval Research Laboratory, Washington, D.C, Callections were made on Army Chemical Corps Type V filters, 200 sq in, area of heavy asbestos fiber composition, Collection No. 204D 204A 204B 130 514-P 204E Volume, Collection Period Apr, Oct. Oct. Oct, Apr. Apr. cu ft x 1078 5—8, 1953 2—6, 1953 6-9, 1953 12-15, 1953 3—5, 1954 8-10, 1954 4.5 1.7 3.4 3.4 2.92 2.6 Sr**/10* cu ft, dis /min 18.6 + 0.7 41.1 + 3.0 30.5 41.1 70 +12 9147 6,4 +4 0.2 204C Apr. $—11, 1954 L.7 125 +5 204F Apr. 10—12, 1954 3.4 258 +6 515-P 204G Apr. 12—14, 1954 Apr. 15-17, 1954 1.95 3.7 65.5 + 4.6 11.0 + 0.5 204H3 Apr. 17-19, 1954 2,8 20.7 + 0.6 516-P 895-P 517-P 896-P Apr. May May May 3.0 2.33 2.76 2.59 32.2 210 31,3 120 518-P 897-P 519-P May 24—26, 1954 May 28-30, 1954 June 1—3, 1954 2.61 3.80 2.90 216 +11 133 +7 68.3 + 4.1 898-P 899-P June 14—17, 1954 dune 23—26, 1954 4.45 3.79 7946 5143 520-P 521-P 522-P 900-P 901-P July July July July Aug, 1.88 2,56 3.66 2.95 5.41 470+ 2.4 73.5 + 5.2 48,.0+ 3.9 200 + 10 59 +5 $03-P 904-P Aug, 28-29, 1954 Oct, 1-3, 1954 1.82 3.39 380 + 25 112 +7 905-P 906-P Oct, 5-8, 1954 Oct. 16-18, 1954. 3.56 2.69 104 +6 198 + 14 902-P 29—May 1, 1954 5-7, 1954 11-13, 1954 17-19, 1954 16-17, 1954 24-26, 1954 26-29, 1954 30—Aug. 2, 1954 2—7, 1954 Aug. 7—9, 1954 * 2.92 + 2.6 + 12 + 2.2 +7 210413 907-P Oct, 26-28, 1954 2.26 251+ 17 401-P 908-P 909-P Nov. 1-3, 1954 Nov. T—8, 1954 Nov. 15-16, 1954 2.9 1.15 1.28 12047 225 + 14 175 + 10 9$10-P 402-P Nov. 22—25, 1954 Dec. 1—2, 1954 1.96 1.6 194 + il 103 + 4 411-P Jan, 3—4, 1955 1,26 281+ 6 412-P Feb. 5—6, 1955 L.7 12745 413-P Feb, 10-12, 1955 2.9 241 +10 913-P Feb. 17—18, 1955 1.51 191411 523-P Feb. 22—23, 1955 1.41 202 +11 524-P 525-P Mar, 3~—4, 1955 Mar. 7-8, 1955 1.76 1.54 270 + 13 394 + 20 526-P Mar. 13—14, 1955 1.07 267 + 16 527-P 914-P 528-P Mar. 16—17, 1955 Mar. 21—23, 1955 Mar, 22-23, 1955 1.62 2.27 1.74 310 +4 15 98 +7 393 + 20 529-P Mar, 27—28, 1955 1.80 9445 773-P Apr. 4-—5, 1955 1.32 844+4 774-P Apr. 11-12, 1955 1.93 71.54 3.3 39