United States
Environmental Protection
Agency *
Office of Radiation Programs
Las Vegas Facility
P.O. Box 15027
Las Vegas NV 89114
ORP/EAD 79-2
March 1979
Radiation
EPA
An Investigation of
Energy Densities
in the Vicinity of Vehicles
with Mobile Communications
Equipment
and Near a Hand-held
Walkie Talkie
T ,TPJ? A. RY
^Jr^'" i^'^L-i' i'KOTECTION AGENW
ED1SGH, H. J- C'iBU
-------
AN INVESTIGATION OF ENERGY DENSITIES
IN THE VICINITY OF VEHICLES WITH MOBILE COMMUNICATIONS EQUIPMENT
AND NEAR A HAND-HELD WALKIE TALKIE
Donald L. Lambdin
March 1979
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Radiation Programs
Electromagnetic Radiation Analysis Branch
P.O. Box 15027
Las Vegas, Nevada 89114
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DISCLAIMER
This report has been reviewed by the Office of Radiation
Programs - Las Vegas Facility, U.S. Environmental Protection
Agency, and approved for publication. Mention of trade names or
commercial products does not constitute endorsement or recommenda-
tion for their use.
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PREFACE
The Office of Radiation Programs of the U.S. Environmental
Protection Agency carries out a national program designed to
evaluate population exposure to ionizing and nonionizing radiation/
and to promote development of controls necessary to protect .the
public health and safety. This report examines exposure levels
in and around several varieties of vehicles equipped with mobile
communications equipment and investigates exposure levels near
the head of a walkie-talkie operator. Readers of this report are
encouraged to inform the Office of Radiation Programs of any
omissions or errors. Comments or requests for further information
are also invited.
Floyd L. Galpin, -mrector
Environmental Analysis Division
Office of Radiation Programs
iii
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TABLE OF CONTENTS
LIST OF FIGURES
LIST OF TABLES
ACKNOWLEDGMENT
INTRODUCTION
INSTRUMENTATION AND EQUIPMENT
PROCEDURE
RESULTS
Vehicles
Hand-Held Walkie Talkie
SUMMARY AND CONCLUSIONS
BIBLIOGRAPHY
APPENDIX
Page
v
viii
ix
1
2
3
5
5
8
9
11
52
iv
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LIST OF FIGURES
Number Page
1 Position of hand-held walkie talkie during
energy density measurements 18
2 Maximum energy densities (nJ/m3); 1973 Plymouth
Fury 4-door sedan (interior); Transmitter: 60
watts, 164.45 MHz lq
3 Maximum energy densities (nJ/m3); 1974 Ford
Torino Station Wagon (interior); Transmitter: 60
watts, 164.45 MHz 20
4 Maximum energy densities (nJ/m3); 1976 Ford
Maverick 4-door sedan (interior); Transmitter:
100 watts, 41.31 MHz 21
5 Maximum energy densities (nJ/m3); Interior of
truck #1 (1973 Dodge D200); Rear window screen
in place; Transmitter: 100 watts, 41.31 MHz 22
6 Maximum energy densities (nJ/m3); Interior of
truck #1 (1973 Dodge D200); Rear window screen
removed; Transmitter: 100 watts, 41.31 MHZ 23
7 Maximum energy densities (nJ/m3); Interior of
truck #2 (1978 Dodge Power Wagon 150); Transmitter:
100 watts, 41.31 MHz 24
8 Maximum energy densities (nJ/m3); Interior of
truck #3 (1978 Dodge Power Wagon 150); Transmitter:
100 watts, 41.31 MHz 25
9 Maximum energy densities (nJ/m3); Interior of
truck #4; (1977 Chevrolet Custom Delux 20);
Transmitter: 100 watts, 41.31 MHz 26
10 Maximum energy densities (nJ/m3); 1973 Dodge
Tradesman 300 (interior); Transmitter: 60 watts,
164.45 MHz 27
11 Maximum energy densities (nJ/m3); 1971 Chevrolet
Chevyvan 30 (interior); Transmitter: 60 watts,
164.45 MHz 28
12 Exposure to head areas of passengers in sedans
(nJ/m3) 29
-------
4ft
LIST OF FIGURES (Continued)
Number Page
13 Exposure to head areas of passengers in
pickup trucks (nJ/m3) 30
14 Exposure to head areas of passengers in vans
(nJ/m3) 31
15 Maximum energy densities (nJ/m3); 1973 Plymouth
Fury 4-door sedan; Transmitter: 60 watts,
164.45 MHz 32
16 Typical energy densities (nJ/m3); 1973 Plymouth
Fury 4-door sedan; Transmitter: 60 watts,
164.45 MHz 33
17 Maximum energy densities (nJ/m3); 1974 Ford Torino
Station Wagon; Transmitter: 60 watts, 164.45 MHz 34
18 Typical energy densities (nJ/m3); 1974 Ford Torino
Station Wagon; Transmitter: 60 watts, 164.45 MHz 35
19 Typical energy densities (nJ/m3); 1976 Ford
Maverick 4-door sedan; Transmitter: 100 watts,
41.31 MHz 36
20 Typical energy densities (nJ/m3); 1976 Ford
Maverick 4-door sedan; Transmitter: 100 watts,
41.31 MHz 37
21 Typical energy densities (nJ/m3); 1976 Ford
Maverick 4-door sedan; Near antenna and other
top areas 38
22 Maximum energy densities (nJ/m3); Truck #1 (1973
Dodge D200); Transmitter: 100 watts, 41.31 MHz 39
23 Maximum energy densities (nJ/m 3) ; Truck #1 (1973
Dodge D200); Transmitter: 100 watts, 41.31 MHz 40
24 Maximum Energy Densities (nJ/m3); Truck #2 (1978
Dodge Power Wagon 150); Transmitter: 100 watts,
41.31 MHz 41
25 Maximum energy densities (nJ/m3) ; Truck #2 (1978
Dodge Power Wagon 150); Transmitter: 100 watts,
41.31 MHz 42
va
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LIST OF FIGURES (Continued)
Number
26 Maximum energy densities (nJ/m3); Truck #3
(1978 Dodge Power Wagon 150); Transmitter: 100
watts, 41.31 MHz 43
27 Maximum energy densities (nJ/m3); Truck #3
(1978 Dodge Power Wagon 150); Transmitter: 100
watts, 41.31 MHz 44
28 Maximum energy densities (nJ/m3); Truck #4
(1977 Chevrolet Custom Delux 20); Transmitter:
100 watts, 41.31 MHz 45
29 Maximum energy densities (nJ/m3); Truck #4 (1977
Chevrolet Custom Delux 20); Transmitter: 100
watts, 41.31 MHz 46
30 Maximum energy densities (nJ/m3); 1973 Dodge
Tradesman 300; Transmitter: 60 watts, 164.45 MHz 47
31 Maximum energy densities (nJ/m3); 1973 Dodge
Tradesman 300; Transmitter: 60 watts, 164.45 MHz 48
32 Maximum energy densities (nJ/m3); 1971 Chevrolet
Chevyvan 30 with fiberglass top; Transmitter:
60 watts, 164.45 MHz 49
33 Energy densities (nJ/m3); 1971 Chevrolet Chevyvan
30 with fiberglass top; Transmitter: 60 watts,
164.45 MHz 50
34 Energy densities (nJ/m3); Head area exposure from
a Motorola HT-220 walkie talkie 51
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LIST OF TABLES
Number ' Page
1 Energy densities measured (nJ/m3); Passenger cars 12
2 Energy densities measured (nJ/m3); Pickup trucks 14
" «,
3 Energy densities measured (nJ/m3); Vans ' 16
Vlll
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ACKNOWLEDGMENT
The author wishes to thank Edwin Mantiply for his assistance
in operating the communications equipment while measurements were
being made.
A special thanks is due David Ball for his superb illustra-
tions.
IX
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f
INTRODUCTION
With the rapidly increasing utilization of mobile communica-
tions equipment, an examination of potential exposure to persons
in and around vehicles so equipped becomes of interest. This
report studies exposure levels associated with a variety of
vehicles equipped with 60 and 100 watt transmitters, broadcasting
at 164.45 and 41.31 MHz respectively.
Measurements were made in the near vicinity (inside and
outside) of each vehicle as well as at moderate distances (6 feet
and 12 feet, two of the distances used in a recent citizen's band
mobile radio study ). A variety of antenna locations were
explored on similar vehicles. Special attention was given to
those areas where persons might be located during transmissions.
Maximum exposure levels were searched out at each given location.
Measurements inside the vehicle were usually made with a subject
seated in the area being measured if that site normally accommo-
dated a person. This was done to take into account the body's
field concentrating effects. A report by the National Bureau of
2
Standards showed maximum exposure levels occurred at sharp
corners or edges, orifices such as wheel wells, and in the
vicinity of a passenger's head; therefore, these areas were
thoroughly examined. Comparisons were also made on vehicles with
and without metallic shading screens on the rear window near the
antenna mount.
•> --
A separate investigation was made of exposures around the
head of a person operating a walkie-talkie.
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INSTRUMENTATION AND EQUIPMENT
The survey instrument used in this investigation was one
developed by the National Bureau of Standards. A detailed
description of this unique device, model EDM-3, can be found in
a previous EPA Technical Note . The instrument measures energy
densities from .03 to 3000 nJ/m3 and is uniform over the frequency
range 10 MHz to 1 GHz.
Two types of transmitters were used: the 60 watt Motorola
Motrac at 164.45 MHz and the 100 watt General Electric MT74TDN22
at 41.31 MHz. The antennas used were either the ASP 446 base-
loaded with 3dB gain or the Phelps Dodge 551-509 base loaded whip
antenna with 2-1/2 dB gain.
The walkie-talkie was a Motorola HT-220, operating at 164.45
MHz with an output of 1.8 watts.
The vehicles investigated were selected from those used by
the EPA for off-site monitoring or general purpose. A complete
list is found in Appendix 1.
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PROCEDURE
Two persons were involved in making measurements. One was
located outside the vehicle with the NBS instrument; the other,
seated inside the vehicle, keyed the transmitter and served as a
representative driver or passenger whose presence would perturb
the EM field. The sensing elements of the EDM-3 are in a small
volume at the end of a rod approximately one meter in length. In
order to measure inside the vehicle, the probe was inserted
through an open window from a position outside so that only the
transmitter operator perturbed the field. Furthermore because of
erroneous measurements at closer distances, the sensing volume
was kept greater than 2 inches from any surface. An attempt was
made to read the meter scale to two significant figures; however,
because of rapidly changing field strength over very short dis-
tances, it was often impossible to hold the sensing element
steady enough to obtain a stable reading. Maximum values were
often instantaneous peak readings which might vary 50 percent to
100 percent during the actual measurement due to small position
fluctuations. No critical reading was recorded which could not
be repeated when measured a second time. In many instances, both
maximum and minimum values were recorded for a given area.
Although measurements were made in terms of electric field
energy densities (nJ/m3), they may be compared to the American
National Standards Institute's standard for continuous occupa-
tional exposure (40,000 v2/m2) by the expression: UE(nJ/m3) =
0.00443E2(v2/m2) . In terms of electric field energy density,
the standard becomes 177 nJ/m3, which will be used as the refer-
ence standard here. It should be noted that the ANSI standard
does not convert directly to OSHA's 10 mW/cm2 value, which is
applicable only to far field measurements. The ANSI standard was
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conservatively derived to yield a rounded off number (194 v/m =
200 v/m = 40,000 v2/m2).
An example of a data collection form is shown in Appendix 2.
Values were recorded both on a tally sheet and on multiview
vehicle drawings.
Exposures at the various body locations were usually deter-
mined with a subject sitting in the specified seat position. For
comparison, a few measurements were taken with the seat empty.
At all other locations inside and outside the vehicle, measure-
ments were made without field disturbance by a person. Generally,
only maximum readings were reported at locations outside each
vehicle. In addition to making measurements close to the vehicle,
exposures were defined at 6- and 12-foot distances, and at 3- and
6-foot heights above ground level.
A separate abbreviated investigation was made of exposure to
the head from a hand-held walkie-talkie. The unit had a 5-inch
antenna mounted just above the speaker/microphone. During
measurement it was held normally, in the right hand, which placed
the antenna directly opposite and about 2-3 inches from the
operator's right eye (Figure 1).
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RESULTS
VEHICLES
Measured values have been tabulated separately for passenger
cars, pickup trucks and vans (Tables 1, 2, and 3). Furthermore,
each table is divided into four major groups of measurements;
those made inside the vehicle where persons may be seated, other
measurements inside the vehicle (both of these groups are illus-
trated in Figures 2-14), major sites outside but close to the
vehicle (illustrated in Figures 15-33) and those made at various
distances from each vehicle. In Tables 1, 2, and 3; single
numbers represent maximum observed values in the given area,
numbers separated by a dash (e.g., 0.1-1.1) are minimum and
maximum values observed in the same general area; numbers sep-
arated by a slash (e.g., 2.0/18) are the smallest and largest
maximum values observed in more than one similar area such as
wheel wells, windows, and potential locations for gas tank
fillers. (In the case of gas tank fillers, three readings were
made: one at the actual location of the filler, and two more
where gas fillers might be on different makes of similar vehicles.)
Each table is arranged so that the same area in similar vehicles
may be compared directly.
Looking at the inside of each vehicle where persons would be
sitting (Figures 2-14), in most cases, maximum exposures occur in
the vicinity of the head and near the driver's hands (when on the
steering wheel).
The head area was explored in greater detail as shown in
Figures 12 to 14. Here, the highest values (up to 120 nJ/m3)
were observed in pickup truck cabs, the lowest (1.0 nJ/m3), in
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one of the sedans and one of the vans. An interesting variation
is seen in pickup #1 having a metallic screen in the rear window
(Figure 13a). When the screen is removed, exposure to the head
approximately doubles. Other comparisons of head exposures may
be made, most of which show expected results. Exposures are
lower in the standard sedan with a 60 watt transmitter (Figure
12a) than in the compact sedan with 100 W transmitter (Figure
12c), antennas being in comparable locations. This is probably
due not only to the higher power output, but also to more exten-
sive roof shielding in the larger sedan. Exposures in the region
where the driver's head would be in the station wagon when the
seat is empty are substantially less than those when the seat is
occupied (Table 1 and Figure 12b). A similar comparison in a
pickup truck cab, but looking at other regions of the body,
(Table 2, Truck 3) does not show the same relative reduction as
was just noted in the head region of the station wagon. This is
probably caused by the seat position with respect to the antenna
(mounted above rear window in the pickup truck). The presence of
the body, in addition to concentrating the field at the head,
also causes shielding in the gonadal area. The importance of
antenna position is clearly seen in Figure 13. Those trucks
having a roof mount (Figure 13a, b, and c) show head exposures 5
to 20 times greater than the one with a rear fender mount (Figure
13d). There is also less head exposure if the antenna is in the
center of the roof (Figure 13c) rather than near the rear window
(Figure 13d and b). Values measured inside the two vans (Table 3
and Figure 14) show relatively low readings, similar to those in
the Plymouth sedan (Table 1 and Figure 12a). This is undoubtedly
due to the relatively large roof area. A notable exception
occurs in the modified Chevrolet van at the driver's position.
Here, the antenna is directly in front of the driver, with the
most intense field occurring about 1-2 feet above his head. The
head exposure is significantly greater if the driver stands up
with his head above the metal frame inside the fiber glass
ceiling (Figure 11 and Figure 14b).
-------
Other areas inside each vehicle where exposures are consis-
tently higher than average include the steering wheel and rear
view mirror (windshield mount). The peak exposure in each case
is generally defined by very small dimensions, falling off rapidly
within an inch or two.
Window areas were measured in two ways. If the window was
fixed, measurements were made both on the inside and outside.
Where the window was a roll-down type (side window) measurement
was made once only with the window in the down position. All
side window measured values are shown on outside view figures
(Figures 15-32). Most yindows had one "hot" spot, usually within
2 inches of the top boundary and near the center (Figures 19, 22,
32). Again, this "hot" spot was defined within a small area.
The sites showing lowest exposure levels occurred in areas
most effectively shielded from the antenna - usually away from
window areas. Included are foot wells, the gonadal area:of a
subject (body shielding), and inside luggage compartments or
truck beds.
Areas outside, but in the near vicinity of the vehicle,
which showed above average exposure levels included some wheel
wells, certain sharp or well defined corners or edges, and
protuberances such as gas caps, door handles and rear view
mirrors. The 1971 Chevolet van (Table 3, Figures 32 and 33)
showed a single highly elevated level of 400 nJ/m3 near the cowl
mounted antenna. The highest values not directly at the antenna
site occurred on a pickup truck with a rear mounted antenna
(Truck #4, Table 2, Figures 28 and 29). Here, the sharp corners
of the rear fenders measured 120 nJ/m3 and the left rear wheel
well, 72 nJ/m3. The position of the antenna apparently influences
these exposures. The 72 nJ/m3 value for the left rear wheel well
is in contrast to the right front wheel well's 2.0 nJ/m3., a
remote location with respect to the antenna. Antennas located
-------
more centrally produce more uniform exposure levels at similar
sites (e.g., wheel wells and bumpers).
Outside exposures of the 1976 Ford Maverick sedan (Figures
19, 20 and 21) were defined in greater detail than those for the
other sedans, as the measured field intensities were highest for
this vehicle (it was smaller than the other sedans and had the
highest transmitter power output). With the antenna mounted in
the direct center of the roof top, exposures are noticeably
symmetrical about the vehicle. Highest levels were predictably
at protuberances (bumpers, door handles, and outside mirrors),
fender edges, the top center areas of windows, and near the
antenna. A diagram of the roof (Figure 21) shows that at distances
closer than 6 inches to the antenna, equivalent occupationally
defined exposure limits may be exceeded (177 nJ/m3).
Exposures measured at distances of 6 and 12 feet from each
vehicle were considerably lower than those measured at the vehicle
Average exposures were about 0.5 nJ/m3 with maximum values of 1
to 2 nJ/m3.
HAND-HELD WALKIE TALKIE
The separate investigation of exposures resulting from the
operation of a hand-held walkie talkie shows a maximum energy
density to the head area of greater than 200 nJ/m3 (Figure 34).
This exposure was found near the eye closest to the antenna. The
exposure rapidly diminishes by a factor of 10 within 1 or 2 inches
of the maximum exposure site.
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SUMMARY AND CONCLUSIONS
Electric field energy densities were investigated in and
around nine separate vehicles using mobile communications equip-
ment, as well as in the near vicinity of a hand-held walkie
talkie.
The only instances in which the current ANSI standard (177
nJ/m3) was exceeded occurred within 6 inches of an active antenna.
In most cases, the antenna was installed at a point on the vehicle
where human contact or approach within 6 inches would be minimized
;(roof mounts). Two vehicles had antennas on or near fenders
where exposure levels exceeding 177 nJ/m3 to part of the body
would be possible. In the case of the cowl mounted antenna on
the Chevrolet van, high exposures to the head area would be
possible to a person working in the windshield area (e.g., washing
windows). The most likely event leading to exposures exceeding
177 nJ/m3 occur with the hand-held walkie talkie (200 nJ/m3 at
the eye). The current standards reflect occupationally acceptable
levels. It might be well to note that several other areas,
inside and outside of each vehicle, as well as near the walkie
talkie, showed exposures exceeding 10 percent of the current
standard (17.7 nJ/m3). Of the major sites measured and tabulated
in the near vicinity of passenger sedans, about 5 percent of
exposures exceeded 18 nJ/m3. Approximately 10 percent of the
measured values close to and inside the two vans exceeded 18 nJ/m3
and nearly 40 percent of those associated with pickup trucks
exceeded that value. Exposure levels at 6 feet or greater from
any vehicle were much lower than 18 nJ/m3. Since the two carrier
frequencies investigated (41.31 MHz and 164.45 MHz) were transmitted
with 100 W and 60 W respectively, it is believed that these
-------
measured exposures represent maximum probable exposure from
typical mobile communications systems.
The walkie-talkie is representative of a "worst case"
situation, having the antenna located within 3 inches of an eye,
10
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BIBLIOGRAPHY
1. Bronaugh, E. L. , D. R. Kerns and W. M. McGinnis. "Electro-
magnetic Emissions from Typical Citizens' Band Mobile Radio
Installations in Three Sizes of Vehicles." Institute of
Electrical and Electronic Engineers Symposium of Electro-
magnetic compatability, Seattle, WA, Aug. 2-4, 1977.
Document #77CH1231-0 EMC, pp. 438-443.
2. Adams, J., M. Kauda and J. Shafer. "Near-Field Electric
Field Strength Levels of EM Environments Applicable to
Automative Systems." Electromagnetics Division, National
Bureau of Standards, Boulder, Colorado, unpublished report.
3. Tell, R. A. and P. O'Brien. "An Investigation of Broadcast
Radiation Intensities at Mt. Wilson, California." Environ-
mental Protection Agency Technical Note ORP/EAD-77-2,
April 1977.
4. Tell, R. A. "An Analysis of Radiofreguency and Microwave
Absorption Data with Consideration of the Specification of
Safe Exposure." EPA Technical Note, ORP/EAD 78-2, April
1978.
11
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TABLE 1
ENERGY DENSITIES MEASURED (nJ/m3)
Passenger Cars
Standard Sedan Station Wagon Compact
60W/164.45 MHz 60W/164.45 MHz 100W/41.31 MHz
Roof,Center- Roof,Center,Rear- Roof,Center-
Mounted Antenna Mounted Antenna Mounted Antenna
Location Measured
Inside Vehicle
Driver
1.
2.
3.
4.
5.
6.
Feet
Knees
Gonads
Chest
Hands
Head
Passenger (Rt.
1.
2.
3.
4.
5.
6.
Feet
Knees
Gonads
Chest
Hands
Head
Passenger (Rt.
1.
2.
3.
4.
5.
6.
Feet
Knees
Gonads
Chest
Hands
Head
Passenger (Lft.
1.
2.
3.
4.
5.
6.
Feet
Knees
Gonadt>
Chest
Hands
Head
Front)
Rear)
Rear)
0.7 - 1.0
1.0 - 4.5
1.6
0.7
1.0 - 8.0
0.4 - 1.5
0.1
1.0
0.2
0.6
0.4
0.3
1.1
4.1
0.5
1.1
1.1
3.0
0
0
0
0
.2
.3
.5
.2
0
0
0
0
4
0
0
.1
.4
.2
-
-
.3
.0
.1
.4
—
0.
0.
2.
0.
6
8
0
3
0.3 - 4.0
1.
7.
1.
2.
4.
1.
0.
0.
0.
2.
1.
2.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0 -
0 -
4 -
6 -
2 -
0 -
1 -
2 -
15-
0 -
2 -
0 -
5 -
5 -
0.
7 -
2 -
5 -
05-
4 -
<0.
2 -
0.
8 -
7.
3.
2.
6.
8.
3.
0.
1.
0.
6.
2.
7.
1.
4.
8
1.
1.
2.
0.
4.
1
1.
2
1.
(Seat
Empty )
0 (.27)
0 (.3-. 5)
3 (.2-. 3)
3 (.2-1.0)
4 (.5-1.9)
0 (.4-. 8)
2
7
4
0
4
0
5
4
7
0
5
1
5
1
4
0
.5
2-8
0
0.5
.5
-
3.
4
5-12
1-20
0
0.2
0
0.2
0
1.0
0.6
1
0
1
0.2
0.5
1
1
1
1
0.2
6
.3
-
.1
-
.2
.6
.1
.0
-
"
.1
.2
.1
.2
-
.4
0.
1.
13
1.
1.
6.
0.
8
1
0
0
0
8
12
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TABLE 1 (Continued)
ENERGY DENSITIES MEASURED (nJ/m3)
Passenger Cars
Location Measured
Inside Vehicle
Windshield
Rear Window
Glove Box
Trunk/S tor age
Instrument Cluster
Rear Deck
Side Windows
Outside Vehicle
Wheel Wells
Gas Tank Filler
Windshield
Rear Window
Front Grill/Hood/
Bumper
Trunk Lid/Bumper
Circumference
61
6'
12'
@ 3' Height
@ 6' Height
@ 6' Height
Roof Near Antenna
<6" from antenna
^6" from antenna
^12" from antenna
Edge of Roofline
Standard Sedan
60W/164.45 MHz
Roof,Center-
Mounted Antenna
Station Wagon
60W/164.45 MHz
Roof,Center,Rear •
Mounted Antenna
Compact
100W/41.31 MHz
Roof/Center-
Mounted Antenna
2.
1.
0.
0.
1.
1.
0.
2.
1.
1.
1.
1.
0.
0.
0
0
5
2
0
0
6
0
0
0
0
5
3
2
-13.
-10.
4.4
-
-
-
1.
5.
4.
/12.
/
/
-
0.
2.
7.
-10.
_
^"
-
0.2
4.
9.
0.
0.
0
0
5
0
0
0
84
5
0
0
0
0
8
7
2
3
0
0
0
2
0
2
2
0
0
0
0
0
.0
.0
.5
.8
.5
.0
.6
.2
.0
10
.5
.4
.2
.6
.3
-17.
-10.
- 1.
- 7.
- 3.
—
/18.
/ 1.
/ 2.
- 9.
.0
- 2.
- 3.
- 0.
- 1.
- 0.
0
0
0
0
0
0
3
5
0
8
8
9
7
9
4.0 - 20
4.0
0.4 - 1.0
0.2 - 1.0
2.0
14.0
2.0 / 6.0
10 / 15
20.0
9.0
16.0 - .20.0
12.0 - 20.0
0.2 - 0.6
0.1 - 0.6
3000 plus
100
50
20/30
13
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TABLE 2
ENERGY DENSITIES MEASURED (nJ/m3)
Pickup Trucks
Transmitter Power = 100W
Frequency = 41.31 MHz
Truck #: #1
Antenna: Roof
Location: Rear
Screened Rear Window
Without (With
Screen Screen)
Inside
Driver
1. Feet
2. Knees
3 . Gonads
4. Chest
5 . Hands
6. Head
Driver #2
1. Feet
2. Knees
3. Gonads
4. Chest
5. Hands
6. Head
Passenger
1. Feet
2. Knees
3. Gonads
4. Chest
5 . Hands
6. Head
Windshield
Rear Window
Glove Box
Dash
Side
Windows
2.
4.
0.
0.
1.
1.
4.
2.
0.
0
0
0
5
1
8
0
0
35
45
0
5
23
-30
-85
.3
- 1.
- 0.
- 6.
- 1.
-62
-11
- 3.
6
2
0
7
0
(0
(2
(0.5)
(1.5)
(0.3)
3 - 2.2)
0 -20)
(2.0 -32)
(0.5)
(1.5)
(0.5)
(.6 - 1.2)
#2
Roof
Rear
2.9
6.2
1.2
1.7
2.3
72
72
48
18
4.0
17/21
#3
Roof
Center
(0.
(2,
(0,
(0.
(0,
(2.
.2
,C
.2
.2
.2
,0
- 0.
- 4.
- 0.
- 2.
-40)
-41)
,8)
.0)
.4)
,2)
i
i
2.
8.
10.
1.
60
120
6
6
0
2
1.
6.
5.
1.
40
30
4
0
0
5
#4
Fender
Rt.-Rear
(Whip)
(Seat
Empty)
1.5(0.4)
4.0(0,
1.5(4,
2.2 (2,
4)
8)
5)
1.4(2.4)
30 (5.5)
48
19
19
19
14
0.6
1.4
4.0
0.6
5.0
6.0
0.05
0.5
"0"
0.15
0.5
4.0
12.0
10.0
0.3
0.6
3.6/9.0
14
-------
TABLE 2 (Continued)
ENERGY DENSITIES MEASURED (nJ/mS)
Pickup Trucks
Transmitter Power = 10OW
Frequency - 41.31 MHz•
Truck #:
Antenna:
Location:
Outside
Wheel Wells
Gas Tank Filler
Windshield
Rear Window
Front Grill/Hood/
Bumper
Rear Storage/
Bumper
Circumference
6' @3' Height
6' @ 6' Height -
12' @ 61 Height
#1
Roof
Rear
1.0 /10.0
8.0 /24.0
14
-38
8.0 -22
0.4 - 0.8
0.5 - 1.3
0.1 - 0.6
#2
Roof
Rear
8.0 /75
30 /80
68
72
70
3.0 -60
0.4 - 0.9
0.4 - 1.1
0.1
#3
Roof
Center
2.7 /19
4.8 /13
48
19
32
8 -22
0.8 - 1.4
1.0 - 2.2
0.4 - 0.6
#4
Fender
Rt.-Rear
(Whip)
1.0 /72
12 /38
12.0
12.0
12
120
0.2 - 1.2
0.8 - 1.2
0.1 - 0.4
15
-------
TABLE 3
ENERGY DENSITIES MEASURED (nJ/m3)
Vans
60W/164.45 MHz
Location
Inside
Driver
1.
2.
3.
4.
5.
6.
Feet
Knees
Gonads
Chest
Hands
Head
Standing
Passenger
1.
2.
3.
4.
5.
6.
Feet
Knees
Gonads
Chest
Hands
Head
Windshield
Glove Box
Instruments
Interior
Front
Rear
Side Windows
1973 Dodge
Standard
No Side or Rear
Windows
Antenna: Roof-Center
Over Cab
Base Loaded
0.2
1.0
0.2 - 0.8
0,
0
2 - 0.4
2 - 0.9
0.3 - 2.5
1971 Chevrolet
Modified
High Fiberglass Roof
One Side Window
Left Front Cowl
Whip
0.2
0.1 - 0.4
0,2 - 0.4
<0.2 - 0.4
0.1 - 0.8
0.3 - 1.0
0.3 - 1.8
0.5
0.5 - 1.5
40 max (near AC)
<0.2
0.5 / 2.8
0.8 - 2.0
1.6 - 4.0
3.0 - 4.0
0.8 - 2.2
2.0 -10.0
2.4 - 7.0
40 (Head in
Fiberglass
Section)
0.8 - 1.8
2.0 - 3.0
1.5
1.2
2.0 - 3.0
0.5 - 2.5
5.0 -13
13
4 -10
13
13
2.0 / 2.5
16
-------
TABLE 3 (Continued)
ENERGY DENSITIES MEASURED (nj/m3)
Vans
60W/164.45 MHz
Antenna
Location
Outside
Wheel Wells
Gas Tank Filler
Windshield
Rear Window
Front Grill/Hood
Rear Area
Circumference
6' @ 3' Height
6' @ 6' Height
12' @ 6' Height
1973 Dodge
Standard
No Side or Rear
Windows
: Roof-Center
Over Cab
Base-Loaded
0.1 / 0.5
<0.1 / 2.0
1.0 - 6.0
0.5 - 3.0
0.1 - 0.4
0.2 - 0.7
0.1 - 0.2
1971 Chevrolet
Modified
High Fiberglass Roof
One Side Window
Left Front Cowl
Whip
0.1 /IB
<0.1 / 3.0
10-400 (near
antenna)
2.5
1.0 -32
0.1
<0.1 - 0.4
0.4 - 1.4
0.2 - 0.4
17
-------
Figure 1. Position of Hand-held Walkie Talkie During
Energy Density Measurements
18
-------
1.5 (INSIDE TRUNK)
1.0 4.5 1.6 0.3
Figure 2. Maximum Energy Densities (nJ/m3)
1973 Plymouth Fury 4-Door Sedan (Interior)
Transmitter: 60 watts, 164.45 MHz
19
-------
3.0
1.0
3.0 0.2 1-1 1-4 0.8
7.0
2.0
7.0 3.0 2.3 0.1 4.5 0.1
2.5 1.7 1.0 7.0 6.0
0.8 4.4 1.5 0.4 1.7 0.2
Figure 3.
Maximum Energy Densities (nJ/m3)
1974 Ford Torino Station Wagon (Interior)
Transmitter: 60 watts, 164.45 MHz
20
-------
1.0
0.5 8.0 0.5 1.1 1.2 1.1
Figure 4. Maximum Energy Densities (nJ/m3)
1976 Ford Maverick 4-Door Sedan (Interior)
Transmitter: 100 watts, 41.31 MHz
21
-------
Figure 5. Maximum Energy Densities (nJ/m3)
Interior of Truck ,#1 (1973 Dodge D200)
Rear window screen in place
Transmitter: 100 watts, 41.31 MHz
22
-------
Figure 6. Maximum Energy Densities (nJ/m3)
Interior of Truck #1 (1973 Dodge D200)
Rear window screen removed
Transmitter: 100 watts, 41.31 MHz
23
-------
Figure 7. Maximum Energy Densities (nJ/m3)
Interior of Truck #2 (1978 Dodge Power Wagon 150)
Transmitter: 100 watts, 41.31 MHz
24
-------
Figure 8. Maximum Energy Densities (nJ/m3)
Interior of Truck #3 (1978 Dodge Power Wagon 150)
Transmitter: 100 watts, 41.31 MHz
25
-------
0.3
6.0
Figure 9. Maximum Energy Densities (nJ/m3)
Interior of Truck #4
(1977 Chevrolet Custom Delux 20)
Transmitter: 100 watts, 41.31 MHz
26
-------
Figure 10. Maximum Energy Densities (nJ/m3)
1973 Dodge Tradesman 300 (Interior)
Transmitter: 60 watts, 164.45 MHz
27
-------
1.8
Figure 11. Maximum Energy Densities (nJ/m3)
1971 Chevrolet Chevyvan 30 (Interior)
Transmitter: 60 watts, 164.45 MHz
28
-------
EXPOSURE TO HEAD AREAS IN SEDANS
A. 1973 Plymouth Fury-4 door sedan 60W/164MHz
Driver
1.0
0.4 •
0.5 »X
•1.5
0.5
Passenger L Rear
4.0
Passenger
0.5 • »2.5
0.3 «N I to
passenger R Rear
2.0
0.5.
0.5
B. 1974 Ford Torino station wagon 60W/164MHz
Driver
3.0
2.0 V-^-N. 2.5
1.0 •(
1.0') f.2.5
Driver empty
0.4-0.8
Passenger
7.0
2.0»V
'2.4
•2.0
Passenger L Rear
1.4
•0.8
Passenger R Rear
2.5
•0.5
C. 1976 Ford Maverick-4 door compact sedan 100W/41MHz
Driver
20
8.0 • -^A. 8.0
1-°' >-1.0
Passenger L Rear
Passenger
13
5.0 • ^S. 8.0
6.4
•
0.5
Passenger R Rear
6.0
0.5 •
Figure 12. Exposure to head areas of passengers
in sedans (nJ/m3)
29
-------
EXPOSURE TO HEAD AREAS IN PICKUP TRUCKS
TRANSMITTER - 100W/41.31MHz
a. #1 1973 Dodge 200 with screen in rear window
DRIVER #1 with screen Driver #2 with screen
41
18'
4.0
H8
•2.0
J.1.0
32
15./S.15
6.0 •> f-3-0
r-1.0
Driver #1 without screen
85
42 »/^> 42
11 -N }
' r« 4.0
Passenger #1 without screen
62
4.0
b. #2 1978 Dodge Power Wagon 150
Driver
120
c. #3 1978 Dodge Power Wagon 150
Driver
30
Passenger
72
Passenger
30
d. #4 1977 Chevrolet Costum Deluxe 20
Driver
6.0
Passenger
4.0
Figure 13. Exposure to head areas of passengers
in pickup trucks (nJ/m3)
30
-------
EXPOSURE TO HEAD AREAS IN VANS
TRANSMITTER-60W/164.45 MHz
A. 1973 Dodge Tradesman 300 (no windows in rear section)
Driver
2.5
0.3-
•0.3
Passenger
1.0
*
0-3* J-0.3
B. 1971 Chevrolet Chevy van 30 with fiberglass top
Driver-sitting
7.0
4.0 r"N« 4.0
•3.6
Passenger
2.5
0.5
Driver-standing with
head in fiberglass top area
40
Figure 14. Exposure to head areas of passengers
in vans (nJ/m3)
31
-------
12
FT?
2.0
0.84
Figure 15. Maximum Energy Densities (nJ/m3)
1973 Plymouth Fury 4 Door Sedan
Transmitter: 60 watts, 164.45 MHz
32
-------
Figure 16. Typical Energy Densities (nJ/m3)
1973 Plymouth Fury 4 Door Sedan
Transmitter: 60 watts, 164.45 MHz
33
-------
Figure 17. Maximum Energy Densities (nJ/m3)
1974 Ford Torino Station Wagon
Transmitter: 60 watts, 164.45 MHz
34
-------
2.0
Figure 18. Typical Energy Densities (nJ/m3)
1974 Ford Torino Station Wagon
Transmitter: 60 watts, 164.45 MHz
35
-------
14
15 30
\\
9.0
15
25
50
15
15
25
9.0
Figure 19. Typical Energy Densities (nJ/m3)
1976 Ford Maverick 4-Door Sedan
Transmitter: 100 watts, 41.31 MHz
36
-------
30
1016
A / /
18
15
2° b—f—o 2*°
40
9.0
15
L^\
a A ' 4P
v\1|»
20 12 <—'
Figure 20. Typical Energy Densities (nJ/m3)
1976 Ford Maverick 4-Door Sedan
Transmitter: 100 watts, 41.31 MHz
37
-------
5.0
3,000
Figure 21. Typical Energy Densities (nO/m3)
1976 Ford Maverick 4-Door Sedan
Near antenna and other top areas
38
-------
8.0
Figure 22. Maximum Energy Densities (nJ/m3)
Truck #1 (1973 Dodge D200)
Transmitter: TOO watts, 41.31 MHz
39
-------
20.,
u
,•15
u
Figure 23. Maximum Energy Densities (nJ/m3)
Truck #1 (1973 Dodge D200)
Transmitter: 100 watts, 41.31 MHz
40
-------
3.0 (INSIDE BED)
80
50*1
Figure 24. Maximum Energy Densities (nJ/m3)
Truck #2 (1978 Dodge Power Wagon 150)
Transmitter: 100 watts, 41.31 MHz
41
-------
68
\«
O
y
u
U
72
3.0 (INSIDE BED)
80
1
V
I
s
50
11
7
J
Figure 25. Maximum Energy Densities (nJ/m3)
Truck #2 (1978 Dodge Power Wagon 150)
Transmitter: 100 watts, 41.31 MHz
42
-------
Figure 26.
Maximum Energy Densities (nJ/m3)
Truck #3 (1978 Dodge Power Wagon 150)
Transmitter: 100 watts, 41.31 MHz
43
-------
30
48
V
32
C)
tit
LF
U
19
n^
1
V
(1
l>
t I
J
« U
*
Figure 27. Maximum Energy Densities (nJ/m3)
Truck #3 (1978 Dodge Power Wagon 150)
Transmitter: 100 watts, 41.31 MHz
44
-------
3.6 21
MOUNTED ON
RIGHT SIDE
120
72
120
Figure 28. Maximum Energy Densities (nJ/m3)
Truck #4 (1977 Chevrolet Custom Delux 20)
Transmitter: 100 watts, 41.31 MHz
45
-------
120
21
\
12 30
f
1
M
fc^ ^ ^
\
\
\
0.4
, n
_U
120
Figure 29. Maximum Energy Densities (nJ/m3)
Truck #4 (1977 Chevrolet Custom Delux 20)
Transmitter: 100 watts, 41.31 MHz
46
-------
2.2 (MIRROR)
0.4
11 (MIRROR)
Figure 30. Maximum Energy Densities (nJ/m3)
1973 Dodge Tradesman 300
Transmitter: 60 watts, 164.45 MHz
47
-------
3.0
(WITH PERSON IN SEAT)
6.0
1.0 EMPTY SEAT
0
u
'^3.0
n
\
D
D
2.0
I
Figure 31. Maximum Energy Densities (nJ/m3)
1973 Dodge Tradesman 300
Transmitter: 60 watts, 164.45 MHz
48
-------
2.0
-H3"
3000 •
1000
18
0.1
Figure 32.
Maximum Energy Densities (nJ/m3)
1971 Chevrolet Chevyvan 30 with Fiberglass Top
Transmitter: 60 watts, 164.45 MHz
49
-------
10
Figure 33. Energy Densities (nJ/m3)
1971 Chevrolet Chevyvan 30 with Fiberglass Top
Transmitter: 60 watts, 164.45 MHz
50
-------
>200 20
Figure 34. Energy Densities (nJ/m3)
Head Area Exposure from a
Motorola HT-220 Walkie Talkie
51
-------
APPENDIX
Vehicles with 60 watt/164.45 MHz transmitters
Antenna/
EPA Vehicle No. Year Make Model Type Location
Vans
21429
21316
Sedans
13887
53169
1973 Dodge
Tradesman 300 Van
1971 Chevrolet Chevy van 30 Van
with modified
fiberglass top
ASP 446, roof
mount
Phelps Dodge
whip, front
cowl mount
1973 Plymouth Fury 4 door
1974 Ford Torino
Sedan ASP 446, roof
mount
Station ASP 446, roof
Wagon mount
Vehicles with 100 watt/41.35 MHz transmitters
EPA Vehicle No. Year Make Model
Antenna/
Type Location
Pickup trucks
#1 21622 1973 Dodge
#2 80010
#3 80008
#4 70915
Sedan
92182
1978 Dodge
1978 Dodge
D200
Power Wagon
150
Power Wagon
150
Pickup ASP 446, roof
mount
Pickup ASP 446, roof
mount
Pickup ASP 446, roof
mount
1977 Chevrolet Custom Delux Pickup Phelps Dodge
20
1976 Ford
Maverick
whip, rear
fender mount
4-door ASP 446, roof
compact mount
sedan
52
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO. 2.
ORP/EAD 79-2
4. TITLE AND SUBTITLE
An Investigation of Energy Densities in the Vicinity of
Vehicles with Mobile Communications Equipment and Near
a Hand-Held Walkie Talkie
7. AUTHOR(S)
Donald L. Lambdin
^^/<^5JfbWe^alT^orlAe'cl!8R AAf £fcf
Office of Radiation Programs
Electromagnetic Radiation Analysis Branch
P.O.. Box 18416
Las Vegas, Nevada 89114
12. SPONSORING AGENCY NAME AND ADDRESS
U.S. Environmental Protection Agency
Office of Radiation Programs
Electromagnetic Radiation Analysis Branch
P.O. Box 18416
Las Vegas . Nevada 89114
3. RECIPIENT'S ACCESSION NO.
5. REPORT DATE
March 1979
6. PERFORMING ORGANIZATION CODE
6. PERFORMING ORGANIZATION REPORT NO.
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
13. TYPE OF REPORT AND PERIOD COVERED
Technical Note
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
Exposure levels are examined in and around several types of vehicles equipped
with mobile communications equipment. Additionally, exposure levels are observed near
the head of an individual operating a hand-held walkie-talkie.
v
Measurements of energy densities inside vehicles indicate highest exposures occur
near the head and near the driver's hands (when on the steering wheel). Outside the
vehicles, highest exposure levels occur near sharp edges and corners, wheel wells, and
certain protuberances. Exposure levels are greatly influenced by location of the
antenna and degree of metallic shielding.
Highest exposure levels occur near the operator's eye for a hand-held walkie
talkie.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Exposure levels associated with mobile
communications equipment
Energy density measurement
Exposure levels near hand-held walkie-
talkies
18. DISTRIBUTION STATEMENT
Release to public
19. SECURITY CLASS (ThisReport)
Unclassified
21. NO. OF PAGES
62
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (Rev. 4-77) PREVIOUS EDITION is OBSOLETE
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