In Table 2 are summarized the measurements for major cities in the United
States, including the range of total
radiation levels encountered and an
estimate of the mean annual dose (8).
Most of the readings taken in the
eastern United States are between 10
and 15 yr/hr. Low radiation levels
were found in New Haven, Connecticut; in the state of Vermont; and in
the region north of Charleston, South
Carolina.
Relatively
elevated
City
Range of
radiation
levels
(ur /hr)
New York, N.Y.
Mean
annual
dose
(mrad)
8.2-15.6 (19)
Louisburg, North Carolina.
Measurements in 1957 were made
during part of the period of Operation
Plumbbob, that year’s series of United
States continental weapon tests at the
National Test Station in Nevada, and,
as reported earlier, these tests influenced certain of the measured values
in an important way, particularly in
eastern Arkansas and in the Black Hills
of South Dakota.
The measurements made during
August 1958 were undertaken during
part of the period of Operation Hardtack, the series of United States weapon tests at the Pacific proving ground.
By comparing scintillation detector
readings taken over patches of bare
ground and grassy spots, it was inferred
that nuclear debris had someinfluence
on almost all of these observations.
Wheretest fallout is present, the larger
surface presented by patches of grass
or weeds results in elevated readings as
compared to readings for bare ground.
In April 1959, 84 of the measurements were repeated as close to the
original positions as possible in order
to estimate the effects of fallout on the
initial readings as well as to check the
reproducibility of the data. Reductions
in the readings were observed at almost
all these locations and in some instances
were considerable. In six locations the
reductions were greater than 10 pr/hr,
ranging up to 54 wr/hr in one Arkansas town. If these locations are
excluded, the average reduction was
about 2 wr/hr. These changes probably
are due in large part to the radioactive
decay and dispersion of fallout debris
which affected the original measure-
Atypical
Cosmic
levels
radiation
(ur /hr)
radiation.
(ur for) ~
pil th
91
3.8
usy
4.3
374
Harrisburg, Pa.
11.3-14.3 (2)
104
40
Cleveland, Ohio
Toledo, Ohio
12.4-14.1 (2)
10.1-11.8 (2)
108
89
42
4.1
Chicago,III.
12.2-13.9 (4)
105
4.1
Madison, Wis.
41,8-12.2 (H
(4)
(2)
(2)
(9)
109
1i2
164
172
4.2
45
8.5
7.9
Colorado Springs, Colo.
Grand Junction, Colo.
Albuquerque, N.M.
22.5-26.4 (4)
18.2-20.8 (3)
15.7-16.5 (4)
197
159
132
8.7
7.2
75
25 |
35
449
4; 26.8 (between U.S.
mint and city and
county buildings)
Fu.
Uae
ust
Oklahoma City, Okla.
14.5-12.3 (4)
99
4.6
3.3
Pittsburgh, Pa.
11.5-16.8 (3)
114
35.4
gu ¢
.
35. - 18.1 (over granite
paving stone)
35 4 20.9 (adjacent to
granite U.S. post
office building)
levels
were observed with the scintillation detector along U.S, highway 401 northeast of Raleigh, North Carolina, to the
Virginia line. The highest reading
found with the ionization chamber in
the 1958 measurements, 19.7 pr/hr,
was made on a dirt road off the aforementioned highway, 2 miles south of
ments.
Table 2. Environmental radiation levels measured in principal United States cities. The number of
observations for each range is shown in parentheses. Elevated radiation levels produced by localized
sources are shown in the last column.
Minneapolis-St. Paul, Minn.
Sioux Falls, $.D.
Cheyenne, Wyo.
Denver, Colo.
Amarillo, Tex.
Tulsa, Okla.
—10,6-15.0
13.6-14.0
19.8-20.4
19,2-22.9
14.9-15.8 (4)
12.8-13.9 (4)
98
4.30027
126
6.4
109
-).°
4.2
36.7
Little Rock, Ark.
Memphis, Tenn.
15.5-16.1 (2)
11.0-13.2 (2)
129
99
3.9
3.9
Chattanooga, Tenn.
13.2-14.8 (2)
114
4.0
Bridgeport, Conn.
New Haven, Conn.
Hartford, Conn.
Springfield, Mass.
Worcester, Mass.
Providence, R.I.
10.8-13.8
8.7- 9.1
11.9
12.9-13.9
14.0-16.4
11.1-13.8
100
73
97
109
124
101
3.8
3.8
3.8
3.8
4.0
3.8
34 *
ee
zH#a- 16.2 (near brick
apartment house)
352 18.0 (near brickfaced motel units)
19.7 (on narrow
business street)
23.7
345
3.5.2
33.2
34.590
33-4
3.8
33.7
Boston, Mass.
Portland, Me.
Philadelphia, Pa.
Baltimore, Md.
Washington, D.C.
Lynchburg, Va.
Winston-Salem, N.C.
(2)
(2)
(2)
(2)
(2)
(2)
11.0-14.3 (4)
12.5-13.5 (3)
11.7-12.5
9.0-12.1
11.1-13.3
12.4-15.4
12.9-14.7
(3)
(3)
(3)
(2)
(2)
99
86
99
113
112
15.0-15.2 (2)
123
Charlotte, N.C.
10.6
Charleston, S.C.
13.5-14.5 (3)
Columbia, S.C.
Raleigh, N.C. °
Richmond, Va.
103
(2)
12.1-13.5 (2)
9.8-11.1 (3)
3.8 33.3
106
3.8 543
39 ton
3.90 fu yy
4.2 44%
430 -.4
86
41 375
114
3.7 in +
3.9
108
suo
4.0
85
37.°
3.9 jan
Table 3. Radiation levels in dwellings in the metropolitan New York area. The number of observations for each range is shown in parentheses.
Radiation levels (ur /hr)
Construction and location
Indoors
Apartments
Second floor, brick private dwelling, Bronx
Third floor, brick apartment house, Manhattan
Fourth floor, brick apartment house, Bronx
10.2—12.3 (6)
9,9-12.0 (6)
10.4-10.8 (2)
First floor, brick apartment house, Manhattan
9.6-11.0
Third floor, brick apartment house, Manhattan
11.9-13.5
Fourth floor, brick apartment house, Manhattan
9.0- 9.3
,
One-family dwellings, Long Island
Ranch type, cedar shingle, concrete basement; Roslyn
7.4- 9.2
Split level, cedar siding, concrete basement; East Norwich
Two-story contemporary, brick veneer, glass, cypress
siding; Sea Cliff
Two-story, stone; Freeport
(2)
(2)
(2)
(13)
Outdoors
12.4
10.9
10.7
9.5
8.4 (concrete patio)
§&.0- 9.1 (12)
11.8 (4 ft from brick
8.5— 9.4 (4)
9.6-11.2 (5)
,
10.9
11.0 (50 ft in front
of house)
13.8 (9 ft in front of
wall
house)
One-family dwellings, Staten Island
7.3- 8.7
Native serpentine stone, Radcliff Road
6.5— 7.5
Stone, Bard and Forest Aves.
Westchester granite veneer, Beacon Ave.
(4)
(4)
6.7— 9.8 (4)
One-family dwellings, Westchester County
12,0-13.8 (5)
Three-story dolomite and sandstone, New Rochelle
Wood frame, Pelham
7.3-12.9 (5)
Wood frame, Pelham
Wi nnd Panes
Rl Dashalla
8.7-1t.3 (3)
amvi1sot
.
10.6
11.4
9.8
13.6
{2.1
905