EPA-902/4-78-007
NONIONIZING RADIATION
IN THE
NEW YORK
METROPOLITAN AREA
U.S. ENVIRONMENTAL PROTECTION AGENCY
REGION II
REGIONAL OFFICE OF RADIATION PROGRAMS
26 FEDERAL PLAZA
NEW YORK, NEW YORK 10007
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NONIONIZING RADIATION IN THE NEW YORK METROPOLITAN AREA
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The U. S. Environmental Protection Agency (EPA) has the
responsibility to protect the health and welfare of man and the
environment from adverse effects due to exposure to both ionizing and
nonionizing radiation. Ionizing radiation (including vacuum ultraviolet, x--
rays, gamma rays, and various energetic particles such as betas, protons,
neutrons, alphas) may have sufficient energy to cause ionization and
significant chemical change in the cells of biological tissue fog which the
energy necessary to produce to a frequency of 2.4 x 10 GHZ* (a
wavelength of 1.2 x 10 cm). Nonionizing electromagnetic radiation, as
its name implies, is incapable of producing ionization in biological tissue.
Included in the frequency spectrum of nonionizing radiation are
microwave and radiofrequency radiation. Although environmental levels
of nonionizing radiation were negligible before the 1930's , virtually every
American is now exposed. Sources have proliferated in number as well as
power. Since 1945 electronics,navigation, and communications industries
have flourished and today there are millions of sources operating. The
number of radiofrequency and microwave sources alone is estimated to be
increasing at 15 percent annually. In the ranges of primary interest, the
radiofrequency (10 MHz to 300MHz) and microwave (300 MHz to 300 GHz)
frequencies, sources include the following:
radio and television broadcast stations
radars
satellite communications system earth terminals
point to point microwave communications
mobile communications systems
microwave ovens
industrial heating equipment
Quantum energies associated with microwave radiation at its
extreme of 300 GHz are about 8000 times less than is needed to destroy
cells by ionization; however, radiofrequency and microwave radiation are
absorbed by tissue and do interact with biological systems. The
electromagnetic energy is transformed into increased kinetic energy of
the absorbing molecules, and results in tissue heating. The process of
absorption and distribution in irradiated tissue depends on the radiation
wavelength and its relationship to the physical shape, size and distribution
of a nonuniform system of tissues, the electrical characteristics of tissue
at specific frequencies, and the intensity of the radiation. A complex
tissue structure such as the human body absorbs energy differently in
specific parts,so that localized heating or non-uniform absorption may
result.
Two kinds of effects on humans due to exposure to radiofrequency
and microwave radiation are usually discussed: thermal effects from high-
level exposures, and possible low-level or "nonthermal effects."
g
* GHz, or gigahertz = 10 cycles per second
MHz, or megahertz = 106 cycles per second
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Thermal effects resulting from irradiation with power densities
above 10,000 microwatts/square centimeter, (abbreviated as uW/cm ) and
equivalent to ten milliwatts/cm (mW/cm ), involve tissue heating with
the possibility of thermal damage. They may include increased body
temperature and resulting heat stress, cataract formation, cardiovascular
temperature and resulting heat stress, cataract formation, cardiovascular
effects, testicular effects, and brainwave pattern changes.
Low-leveLeffects are a subject of controversy. Effects of exposure
to 1,000 uW/cm (one mW/cm ) or less have not been well-documented; in
fact, all U. S. scientists do not even agree that they exist. Some Russian
and Czech scientists believe that they occur, but not as a result of
increased tissue temperature (hence "nonthermal" effects). Their views
are based on animal research and statistical studies of workers' exposure
histories and medical records. Considered to be mainly central nervous
sytem effects, symptoms attributed to low-level exposure include
headache, weariness, dizziness, irritability, emotional instability, partial
loss of memory, loss of appetite, cardiovascular effects,
electroencephalogram changes, blood chemistry changes, changes in
respiration, and possible genetic effects.
The exposure limits in protective standards differ widely among
various countries. In Eastern Europe standards are geared to protect
against "non-thermal effects" of long-term exposure to low intensity
radiation. On the other hand, in the U. S. and most Western European
countries, standards were designed with high-level exposures and possible
thermal effects in mind.
In the United States, existing guidelines or standards for exposure to
nonionizing radiation are based on the premise that any direct effect on
health is due to the heat that is generated when radiation is absorbed. In
1971, the Occupational Safety and Health Administration (OSHA) adopted
the American National Standards Institute (ANSI) limit of 10 mW/cm
(milliwatts per square centimeter) for the frequency range of 10 MHz
(megahertz) to 100 GHz (gigahertz) as a consensus standard for
occupational exposure to electromagnetic radiation. The present limit,
defined by ANSI, allows a power density of 10 mW/cm for any 0.1 hour
period or an energy density of 1 mW/cm during any 0.1 hour period. The
present standard gives no upper limit for total exposure. According to a
December 31, 1975, decision, the OSHA standard is considered to be
advisory rather than mandatory. In contrast, the USSR occupational
standards allowed,, for the 300 MHz-300 GHz frequency range cannot
exceed 10 uW/cm for the duration of a working day although greater
exposures are allowed for short periods of time,and the recommended
general population exposure standard is 1 uW/cm (HA74).
EPA has conducted surveys of metropolitan areas as part of a
program to define environmental levels of radiofrequency radiation from a
human exposure standpoint. Accurate electromagnetic radiation intensity
measurements are made to define normal ambient radio-frequency levels
before a decision can be made on the need to establish population
exposure standards. The frequencies studied are shown in Table 1.
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Metropolitan areas studied to date include New York, Boston,
Philadelphia, Washington, Atlanta, Miami, Chicago, Las Vegas, San Diego,
Houston, Portland, and Los Angeles. Further studies are continuing
elsewhere.
In Region II, the New York Metropolitan area was monitored for
radiofrequency and microwave radiation levels. Data for Region II were
measured during the period from August 16 to September 1,1976. The five
boroughs of New York City, Long Island and West Orange, New Jersey
were examined. The results of the measurements are shown in Table 2.
The single maximum reading was for a New Jersey location underneath an
FM antenna where the measured value was 4.6 uW/cm , a figure above
the recommended Soviet standard for general population exposures. While
this location is accessible to the public, it involves little population
exposure. Few people would normally be near the location.
There are two types of data base which are pertinent to analyzing
environmental levels of nonionizing electromagnetic radiation at
frequencies below 300 GHz. The first of these consists of computer files
of source locations and characteristics that permit the calculation of
expected exposure levels if an appropriate model and sufficient source
parameters are available. The second type of data base consists of
reports on studies of specific sources and the ambient environment. Until
recently, only limited data have been available on the ambient
environment.
By comparing population distribution and power density in each area
of interest, population exposure can be determined. Such a comparison is
only an approximation, since relatively few people remain in one place for
a 24-hour period each day. However, the method offers a general
estimate of total exposure. In an unpublished report (AT 76) Athey« et al
reported "the median power density value is agout 0.006 uW/cm witfi
about ]36 of the population estimated to be exposed at levels above 1
uW/cm ." The median exposure estimated for the New York Metropolitan
area is 0.002 uW/cm .
Levels recorded at individual building sites in the cities of New
York, Chicago, and Miami are compared in Table 3. The locations were
specifically chosen to obtain maximum power density measurements in
each city. These locations are specified in the Table. All readings were
taken indoors near windows facing transmitters. It can be seen that some
portion of the general population is exposed to levels that exceed the
Soviet standards.
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Summary
In summary, several points should be noted:
* In small areas«very close to transmitters there are levels of
exposure above 1 uW/cm . In some cases these areas are accessible to the
public.
2
* In New York City the median exposure was 0.00217 uW/cm , wi£h
less than 0.2 % of the population exposed to levels greater than 1 uW/cm .
* There are areas of tall buildings which have higher exposure levels
caused by proximity to broadcasting antennae. Occupants of such areas
are not likely to experience such levels of exposure for long periods of
time since structural materials and window blinds can significantly reduce
actual levels in the buildings.
* Data analysis indicates that the FM band contributes the largest
fraction of radiofrequency environmental exposure between 54 and 900
MHz.
* Various television bands contribute about equal amounts of
environmental exposure.
* Land mobile bands make the smallest exposure contribution to
environmental radiofrequency radiation.
Further study is required before a total picture of the general
population exposure can be drawn. Beyond areas adjacent to transmitter
locations, radiofrequency exposure levels are well below present U. S.
standards, which are based primarily on known thermal effects.
Additional investigation of the low level effects of nonionizing radiations
are being conducted in order to determine an appropriate general
population exposure threshold if this is indeed indicated.
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Table 1
Symbol
Frequencies of Interest
for Microwave Exposure Study
Principal Use
Frequency (MHz)
LVHF
HVHF
FM
LLM
HLM
UHF
VHF television signals
(channels 2-6)
VHF television signals
(channels 7-13)
the FM radio band
Land Mobile bands
Land Mobile bands
UHF television bands
(channels 14-83)
58-88
174-216
88-108
150
450
470-890
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Table 2 Exposure Levels at New York Metropolitan Area Measurement Sites
gower Density by B^nd 0
Description n n
Location 0-2 LVHF
Riverside Park
Central High
Essex Green Ctr.
Mt. Pleasant St.
Channel 68 Tower
Central Park,So.
Central Pk, N.
Ft. Tryon Park
Randall's Is.
Battery Park
Foley Square
E. River Pk.
McCarrey Park
Ft. Green Pk.
Prospect Park
Flatlands
Fort Hamilton
Linden Blvd.
Shore Pkwy
Yankee Stadium
Fordham Univ.
Fordham Radio
Van Cortland Pk.
Cunningham Park
Great Neck
Flushing Meadow
Aqueduct
HLM
TOTAL
042
018
025
*
*
*
085
10
068
036
031
31
32
0056
0092
0086
020
0055
012
062
on
*
049
033
029
057
014
.28n
.027n
.lln
*
*
.032
.0090
.24n
.0031
.77n
.0071
.010
.14
.0010
.0012
.42n
.015n
.0011
.27n
.0018
.13n
*
.80n
.19n
.41n
.0023
.50n
.0011
.083n
.27n
*
*
.016
.058
.10n
.021
.36n
.0065
.011
.19
.0042
.0011
.0017
.083n
.0013
.0055
.0029
.26n
*
.0069
.0020
.42n
.071
.0033
.43n
.25n
1.9
4.6
*
.080
.0*8
.31n
.0026
.0010
.0048
.012
.25
.0017
.63n
.48n
, .051n
.55n
.61n
.0020
.027
.12
.83n
.42n
.57n
.0068
-.0010
.002n
.006n
.030
.26n
.35
.039n
.006n
.039n
.0036
*
•
.033n
.49n
.092n
.36
.33n
.10n
.084n
.37n
.0018
.082n
.023n
*
,69n
.36n
.23n
.026
.36n
*
.071n
.14n
*
*
*
.019n
*
*
.01 On
*
.070n
*
.93n
*
.003n
*
.01 On
*
*
.Olln
*
*
.01 On
*
*
.0086n
*
.018n
.25n
*
*
*
.Olln
*
*
.009n
*
.041n
*
.04Qn
*
.003n
*
.OOln
*
*
*
*
*
,006n
*
*
.0079n
.0018
.00046
1.9
4.6
.35
.13
.085
.00069
.030
.0021
.018
.034
.58
.36
.0033
.0027
.00023
.0033
.0082
.0068
.027
.12
.0092
.0030
.0016
.11
.0052
CTi
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Table 2 (Cont'd)
Description
Location
0-2
LVHF
HVHF
FM
UHF
LLM
HLM
TOTAL
Forest Park
Belmont Park
White Plains Rd.
Throgs Neck
Pel ham Bay Park
Woodmere
WIOK-FM
Grand Avenue Sen.
Mitchel Park
Clove Lakes Park
Willowbrook Pk
Tottenville
Great Kills Pk
012
0052
0095
16
23
0093
*
028
on
017
028
0043
020
.0016
.055n
.50n
.10n
.26n
.18n
*
.027n
.17n
,87n
.26n
.012n
.27
.52n
.0033
.0014
.96n
.0027
.0015
*
.13n
.63n
.0012
.38n
.015n
.0023
.59n
.35n
.24n
.095n
.48n
.30n
.22
.052
.14
.0015
.48n
.Q41n
.42n
.042n
.37n
.84n
.35n
.0010
.0013
*
.76n
.033
.Q035n
.16p
.23p
.0029
*
*
.73p
*
.64p
.0018n
*
*
*
*
.57p
*
*
*
,0020n
*
.OOlln
.016n
*
*
*
*
.0012
*
*
.0028
.0041
.OD30
.0015
.0044
.0033
.22
.053
.17
.0036
.0011
.000068
.0059
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8
Table 3
Maximum Power Densities
At Locations in Some Cities Surveyed
Location Total Fyeld Strength
(uW/cm )
New York City
World Trade Center
(Observation Deck outdoors) 6.8
(Observation deck indoors) 1.2
Empire State Building 32.50
(Inside, 102nd floor near window)
Pan Am Building 10.3
(Inside, facing Empire State Building)
Miami
Office Building at 2 Biscayne Blvd. 96.85*
Chicago
Sears Tower 65.73
(50th floor, inside, nearwindow)
Federal Building 6.47
(39th floor)
* Measurement for 38th floor window facing FM station WIMI only, the
strongest local source.
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References
Athey, T. W., R. A. Tell, and D. E. Janes. "The Use of an Automated
Population Data Base in Population Exposure Calculations," in Proceedings
of the Health Physics Society Eighth MidyearTopical Symposium, pp.24-
36, USEAC Technical Information Center (CONF-741018), Oak Ridge,
Tenn. (1974)
Athey, T. W., R. A. TeU, N. N. Hankin, D. L. Lambdin, E. D. Mantiply, and
D. E. Janes,"Nonionizing Radiation Levels and Population Exposure in
Urban Areas of the Eastern United States," (draft ORP/EAD-77-008)
Hankin, N. N., R. A. Tell and D. E. Janes, "Assessing the Potential for
Exposure to Hazardous Levels of Microwave Radiation from High Power
Sources" (abstract) Health Physics 27;633 (1974).
Hankin N. N., R. A. Tell, T. W. Athey and D. E. Janes,"High Power
Radiofrequency and Microwave Sources: A Study of Relative
Environmental Significance," Proceedings of the Ninth Midyear Topical
Symposium of the Health Physics Society m"Operational Health Physics,
compiled by P. L. Carson,"W. R~I Hardee and D. C. Hunt. Central Rocky
Mountain Chapter, Boulder, Colo., pp 231-38 (Feb. 1976).
Janes, D. E., R. A. Tell, T. W. Athey and N. N. Hankin,"Nonionizing
Radiation Exposure in Urban Areas of the United States," Communication
304,Session No. S.07,Nonionizing Radiation, IVth International Congress of
the International Radiation Protection Association, G. Bresson, editor,
Vol.2, pp 329-332, Paris, France (April, 1977)
Janes, D. E., R. A. Tell, T. W. Athey and N. N. Hankin,"Radiofrequency
Radiation Levels in Urban Areas," Special Supplement in Biology to Radio
Science (Guy A. W., D. R. Justesen, eds) SS-1 (1977).
Rowe, W. D., D. E. Janes, and R. A. Tell, "An Assessment of Adverse
Health Effects of Telecommunications Technology," presented at the
National Telecommunications Conference, Technology Forecasting
Assessment Session, Atlanta, Georgia (November, 1973).
Smith, S. W. and D. G. Brown, "Radiofrequency and Microwave Radiation
Levels Resulting from Man-Made Sources in the Washington, D. C. Area"
(FDA) 72-8015, BRH DEP 72-5,Food and Drug Administration, Rockville
Md. 20857 (1971)
Smith, S. W. and D. G. Brown,"Nonionizing Radiation Levels in the
Washington D. C. area," IEEE Trans., EMC-15,2-6 (1973).
Tell, R. A., Reference Data for Radiofrequency Emission Hazard
Analysis, EPA/ORP,SID 723, Office of Radiation Programs, EPA
Washington, D. C. 20460
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10
Tell, R. A. Broadcast radiation: How safe is safe? IEEE Spectrum 9:4351
(1972).
Tell, R. A., A Measurement of RF Field Intensities in the Immediate
Vicinity of an FM Broadcast Station Antenna, Technical note, ORP/EAD
6-2, Office of Radiation Programs, EPA, Washington, D. C.
20460(January, 1976).
TeU, R. A. and D. E. Janes, Broadcast Radiation—A Second Look published
in Biological Effects of Electromagnetic Waves,selected papers of the U.
S. National Committee of the International Radio Science Union, 1975.
Annual Meeting, Vol.2, pp.363-388 (FDA) 77-8010. C. C. Johnson and M.
L. Shore, editors. Food and Drug Administration, Rockville, Md. 20857
(December 1976.).
Tell, R. A., Unpublished talk, Dec. 1977.
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