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5 Mar
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Dear
ALL,
I
recently visited World Health Organisation's [ WHO ] Website in the
context of scanning it's views on , EMF Radiation Health Hazard in the backdrop of
public outcry against Mobilephone Base Station Towers etc. .
Sample
extract is Copied below for ready reference . Other related hyper links are
also important in this context.
Much
of the references appear to be old. Reason could by that International
organisations ---which are inter-governmental organisations --are very slow and
take years in coming to an agreed text / document which can be project as a
formal doc. on behalf of the Organisation.
One
may also get lot of links leading to vast information in various websites , by
giving " Electromagnetic Hypersensitivity " [ EPH ] as
"Search" command for GOOGLE Search
This
might interest you in view of your known interest in this area .
With
Best Wishes,
A.M. JOSHI
Electromagnetic
fields and public health
Base stations and wireless technologies
Backgrounder
May 2006
May 2006
Mobile telephony is now commonplace around
the world. This wireless technology relies upon an extensive network of fixed
antennas, or base stations, relaying information with radiofrequency (RF)
signals. Over 1.4 million base stations exist worldwide and the number is
increasing significantly with the introduction of third generation technology.
Other wireless networks that allow
high-speed internet access and services, such as wireless local area networks
(WLANs), are also increasingly common in homes, offices, and many public areas
(airports, schools, residential and urban areas). As the number of base
stations and local wireless networks increases, so does the RF exposure of the
population. Recent surveys have shown that the RF exposures from base stations
range from 0.002% to 2% of the levels of international exposure guidelines,
depending on a variety of factors such as the proximity to the antenna and the
surrounding environment. This is lower or comparable to RF exposures from radio
or television broadcast transmitters.
There has been concern about possible
health consequences from exposure to the RF fields produced by wireless
technologies. This fact sheet reviews the scientific evidence on the health
effects from continuous low-level human exposure to base stations and other
local wireless networks.
Health concerns
A common concern about base station and
local wireless network antennas relates to the possible long-term health
effects that whole-body exposure to the RF signals may have. To date, the only
health effect from RF fields identified in scientific reviews has been related
to an increase in body temperature (> 1 °C) from exposure at very high field
intensity found only in certain industrial facilities, such as RF heaters. The
levels of RF exposure from base stations and wireless networks are so low that
the temperature increases are insignificant and do not affect human health.
The strength of RF fields is greatest at
its source, and diminishes quickly with distance. Access near base station
antennas is restricted where RF signals may exceed international exposure
limits. Recent surveys have indicated that RF exposures from base stations and
wireless technologies in publicly accessible areas (including schools and
hospitals) are normally thousands of times below international standards.
In fact, due to their lower frequency, at
similar RF exposure levels, the body absorbs up to five times more of the
signal from FM radio and television than from base stations. This is because
the frequencies used in FM radio (around 100 MHz) and in TV broadcasting
(around 300 to 400 MHz) are lower than those employed in mobile telephony (900
MHz and 1800 MHz) and because a person's height makes the body an efficient
receiving antenna. Further, radio and television broadcast stations have been
in operation for the past 50 or more years without any adverse health
consequence being established.
While most radio technologies have used
analog signals, modern wireless telecommunications are using digital
transmissions. Detailed reviews conducted so far have not revealed any hazard
specific to different RF modulations.
Cancer: Media
or anecdotal reports of cancer clusters around mobile phone base stations have
heightened public concern. It should be noted that geographically, cancers are
unevenly distributed among any population. Given the widespread presence of
base stations in the environment, it is expected that possible cancer clusters
will occur near base stations merely by chance. Moreover, the reported cancers
in these clusters are often a collection of different types of cancer with no
common characteristics and hence unlikely to have a common cause.
Scientific evidence on the distribution of
cancer in the population can be obtained through carefully planned and executed
epidemiological studies. Over the past 15 years, studies examining a potential
relationship between RF transmitters and cancer have been published. These
studies have not provided evidence that RF exposure from the transmitters
increases the risk of cancer. Likewise, long-term animal studies have not
established an increased risk of cancer from exposure to RF fields, even at
levels that are much higher than produced by base stations and wireless
networks.
Other effects: Few
studies have investigated general health effects in individuals exposed to RF
fields from base stations. This is because of the difficulty in distinguishing
possible health effects from the very low signals emitted by base stations from
other higher strength RF signals in the environment. Most studies have focused
on the RF exposures of mobile phone users. Human and animal studies examining
brain wave patterns, cognition and behaviour after exposure to RF fields, such
as those generated by mobile phones, have not identified adverse effects. RF
exposures used in these studies were about 1000 times higher than those
associated with general public exposure from base stations or wireless
networks. No consistent evidence of altered sleep or cardiovascular function
has been reported.
Some individuals have reported that they
experience non-specific symptoms upon exposure to RF fields emitted from base
stations and other EMF devices. As recognized in a recent WHO fact sheet
"Electromagnetic Hypersensitivity", EMF has not been shown to cause
such symptoms. Nonetheless, it is important to recognize the plight of people
suffering from these symptoms.
From all evidence accumulated so far, no
adverse short- or long-term health effects have been shown to occur from the RF
signals produced by base stations. Since wireless networks produce generally
lower RF signals than base stations, no adverse health effects are expected
from exposure to them.
Protection standards
International exposure guidelines have
been developed to provide protection against established effects from RF fields
by the International Commission on Non-Ionizing Radiation Protection (ICNIRP,
1998) and the Institute of Electrical and Electronic Engineers (IEEE, 2005).
National authorities should adopt
international standards to protect their citizens against adverse levels of RF
fields. They should restrict access to areas where exposure limits may be
exceeded.
Public perception of risk
Some people perceive risks from RF
exposure as likely and even possibly severe. Several reasons for public fear
include media announcements of new and unconfirmed scientific studies, leading
to a feeling of uncertainty and a perception that there may be unknown or
undiscovered hazards. Other factors are aesthetic concerns and a feeling of a
lack of control or input to the process of determining the location of new base
stations. Experience shows that education programmes as well as effective
communications and involvement of the public and other stakeholders at appropriate
stages of the decision process before installing RF sources can enhance public
confidence and acceptability.
Conclusions
Considering the very low exposure levels
and research results collected to date, there is no convincing scientific
evidence that the weak RF signals from base stations and wireless networks
cause adverse health effects.
WHO Initiatives
WHO, through the International EMF
Project, has established a programme to monitor the EMF scientific literature,
to evaluate the health effects from exposure to EMF in the range from 0 to 300
GHz, to provide advice about possible EMF hazards and to identify suitable
mitigation measures. Following extensive international reviews, the
International EMF Project has promoted research to fill gaps in knowledge. In
response national governments and research institutes have funded over $250
million on EMF research over the past 10 years.
While no health effects are expected from
exposure to RF fields from base stations and wireless networks, research is
still being promoted by WHO to determine whether there are any health
consequences from the higher RF exposures from mobile phones.
The International Agency for Research on
Cancer (IARC), a WHO specialized agency, is expected to conduct a review of
cancer risk from RF fields in 2006-2007 and the International EMF Project will
then undertake an overall health risk assessment for RF fields in 2007-2008.
Further Reading
ICNIRP (1998)
www.icnirp.org/documents/emfgdl.pdf
IEEE (2006) IEEE C95.1-2005 "IEEE Standard for Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz"
IEEE (2006) IEEE C95.1-2005 "IEEE Standard for Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz"
Related links
For more information contact:
WHO Media centre
Telephone: +41 22
WHO Media centre
Telephone: +41 22
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