DeeMaikee a idaA tae tt tka Leeation * Be * fade oR A ee Range cf nadiation Levels eet ieweke we te Mean Annual Dose (sierercentgens/hr) (illirads)* - ae Average Pressure (inebes fs) oo Atypical Radiation Levels (microroentgens, hr) Harrisburg, i2. 9.6 - 11.9 (2) SE 29.5 - pittsburgh, a. 9.8 - 13.9 (3) $6 29.2 ~ Cleveland, Cnio 10.5 - 11.8 (2) a1 20.4 8.7 - 16.0 (2) 75 29.5 14.9 (over granite paving stone} Chicago, Ill. 10.3 - 11.6 (43 58 2o.4 17.0 (adgacent to Madisoa, ‘Wise. 1o.l - 16.4 (3) Ch. 25.1 9.1 - 12.5) (4) 92 29.3 Sioux Falls,S. Dakota 11.5 - 11.8 (2) 95 28.8 - , Cheyenne, Wyo. 17.2 - 17-6 (2) ike 2h 4 - C Denver, Colo. 16.6 - 319.4 (10) LET 25.0 Toledo, Chio 7 Minneapolis-St. Paul, . Minn. © U.s. Post Office Bldg. of granite construction) - } ; i 3 19.3 - 22.3 (4) 168 2k .2 Grand Junction, Colo. 15.7 - 16.4 (3) 138 25.5 Albuquerque, N. Mexico 13.8 - 14.5 (4) 116 25. Anarillo, Texas 12.9 - 13.0 (4) 108 26. - 2.9 - 10.5 (4) Bi 28.7 ~ Tulsa, Obla. 16.6 - 11.6 (4) 92 29.3 - Little Rock, Ark. 12.5 - 13.3 (2) 166 29.7 - 9.4 - 11.0 (2) 83 29.3 11.1 - 12.3 (2) a5 29.6 13-3 (near brick apartment house } 14.6 (neur brick~-faced notel units) 16.1 (on narrow Memphis, Tenn. Chettanooga, Tenn. i Mint .ind City and County Bligs.) - Colorado “prings, Colo. Cxlehoma City, Okla. q 22.4 (between U.S. . - business street; * Dose in soft tissue, assuming constant dose rate. 8th between Broad and barket) h rad = 100 ergs/em, 1 nicroroentgen/hr = 8.152 mrad/yr. Table I. environmental radiation levels measured in principal United States cities during August, 1957. The nurber of observations for each range are shown in parentheses. alevated radiation levels produced by localized sources are shown in the last column.

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