rh@well.uucp (Robert Horvitz) (03/27/89)
Mike Trout asks if there is any truth to the assertion
that "cellular phones [are] extremely hazardous and probably highly
carcinogenic."
I am not a scientist, but research on the bio-effects of radio-frequency
emissions is something I follow closely. In general, if you want the
lastest news, pointers to new published evidence of bio-effects (beneficial
or harmful), announcements of regulatory action, and pro/con debates among
experts, consult MICROWAVE NEWS, edited/published by Dr. Louis Slesin
(6 bimonthly issues for $250 in the US, $285 to Canada & elsewhere; order
from P.O. Box 1799, Grand Central Station, New York, NY 10163; phone
212-517-2800). My only connection to this publication is as an avid reader
for 7 years. (BTW, the title is misleading: it doesn't just cover the
microwave part of the spectrum. Increasingly, attention is focussing on
the magnetic fields surrounding powerlines and video display terminals as a
health issue.)
To make a long, unfinished story short, there's no definite evidence yet
that radio emissions from cellular phones cause cancer, but there is reason
to fear that over the long term there COULD be harmful effects of SOME sort.
Different parts of the human body resonant at different electromagnetic
frequencies. When radio waves pass through the body, some of the energy
is absorbed - very little, usually, since we are highly "transparent"
to the waves. In theory, the more closely resonant a body is with the
radio waves, the more energy is transferred to the body. The human head
and neck are pretty close to resonance with the frequencies emitted by
cellular phones. ("Hots-spots" in the body for radio absorption are
generally the narrowings - ankles, neck - and places with sharp angles -
armpits, groin.)
If the cellular transmitter and antenna are in the headset, and you hold it
right against your skull, your brain is probably going to absorb quite a bit
of RF energy - probably more than the safety limits set by organizations
like ANSI. But most cellular phones DON'T have the transmitter and antenna
in the headset. The little pig-tail on the roof or window is the radiator.
Depending how far away it is, and how much shielding is provided by the car
roof, frame and seat, your exposure will be less. (Because the interior of a
car is a complex reflective cavity for radio waves, there may be invisible
"hot-spots" where energy of specific frequencies is concentrated. It's hard
to generalize about particular ambient fields. Direct measurement is the
best way to determine the field strength at specific points.)
Beyond that, little is yet known about the bio-effects of radio waves that
are below the threshold where living tissue is measurably heated by energy
absorption. What your source was probably picking up on was a finding that
living DNA can absorb enough energy from pulsed microwaves to fracture. Dr.
Bill Guy (University of Washington) demonstrated in 1985 that rats exposed to
pulsed microwaves had a significant number of tumors induced in their
endocrine systems. Other researchers have confirmed this, and still others
have found pulsed microwaves can cause mutations (chromosome damage) in chick
and rat embryos.
But it is a very long reach from pulsed microwaves to frequency-modulated
UHF radio waves - that's what cellular emits - and from rats to humans
- the resonant frequencies and absorption/dissipation rates are different.
Intuition suggests that pulsing may be more stressful on tissue than FM,
and the longer wavelengths of VHF mean less resonance with the tiny
structures in membranes and cells.
To complicate things further, bio-effects have only been found in certain
COMBINATIONS of power-density, frequency and duration. Unlike exposure to
toxic chemicals, say, exposure to a more intense radio field might actually be
LESS harmful than a less intense field of the same frequency. Same goes for
the duration of exposure: it may be that intermittent exposure is more
- or less! - harmful than continuous exposure. We just don't know.
We live in a sea of man-made radio energy containing all sorts of frequencies
and modulations that we can't see or feel, and we know very little about the
long-term effects. For that reason, it's a shame - willful negligence? -
that the Environmental Protection Agency disbanded its radio effects
laboratory (thank you Ronald Reagan!) and gave up trying to set safety
standards for human exposure (thank you Gramm-Rudman-Hollings!).
I wouldn't hold a walkie-talkie up to my head - or wear a rubber-ducky
antenna on my headband, as some hams do - until we understand more about
the effects. As for cellular, there's much more certain harm being
caused to your privacy (as others have noted, cellular systems BROADCAST
your words over very large areas), and also to your wallet. For those
reasons alone you're better off stopping to use a pay-phone.john@ucbvax.berkeley.edu (John Higdon) (03/30/89)
In article <telecom-v09i0110m02@vector.UUCP>, rh@well.uucp (Robert Horvitz) writes: > As for cellular, there's much more certain harm being > caused to your privacy (as others have noted, cellular systems BROADCAST > your words over very large areas), and also to your wallet. For those > reasons alone you're better off stopping to use a pay-phone. Thank you for your opinion. Unfortunately we now live in the era of COCOTs (or COPTs, as Pacific Bell refers to them), and it is quite literally cheaper in many cases to use a cellular telephone. Putting the inconvenience of trying to locate a pay phone aside, I know that I can always send DTMF to my voice mail with my handheld. Also, I know that long distance will be reasonably priced, that my party and I can hear each other, that I can call anywhere from Napa to Monterey for the same 45 cent charge. I'm afraid, sir, that pay phones are cellular's greatest selling tool. -- John Higdon john@zygot ..sun!{apple|cohesive|pacbell}!zygot!john
rpw3@ames.arc.nasa.gov (Rob Warnock) (03/31/89)
In article <telecom-v09i0115m03@vector.UUCP> (John Higdon) writes: +--------------- | > For those reasons alone you're better off stopping to use a pay-phone. | Thank you for your opinion. Unfortunately we now live in the era of | COCOTs (or COPTs, as Pacific Bell refers to them), and it is quite | literally cheaper in many cases to use a cellular telephone... +--------------- And your call might even go through! This morning I hit the situation head on: I was at a breakfast meeting at Coco's in Sunnyvale, when I wanted to call a later appointment to tell him the meeting was going to run over and I'd be late. Being new to cellular, and still somewhat cautious about costs, I dutifully went towards the payphones in the back. Uh, oh, COCOTs! Well, trying the first phone gave me my party, but then the channel was only 1/2 open: I could hear them but they couldn't hear me! I tried the other phone, but it kept spitting back my coin and saying my number was "invalid" and I had to dial again. So I went back to my table and picked up the handheld... The relief from frustration was *worth* the extra 20 cents! Rob Warnock Systems Architecture Consultant UUCP: {amdcad,fortune,sun}!redwood!rpw3 DDD: (415)572-2607 <=== *Not* the mobile! ;-} USPS: 627 26th Ave, San Mateo, CA 94403
johnw@gatech.edu (John Wheeler) (04/10/89)
In article <telecom-v09i0117m06@vector.dallas.tx.us> Rob Warnock <amdcad! amdcad!rpw3@ames.arc.nasa.gov> writes: >....I was at a breakfast meeting at Coco's in Sunnyvale, when I >wanted to call a later appointment to tell him the meeting was going >to run over and I'd be late. Being new to cellular, and still somewhat >cautious about costs, I dutifully went towards the payphones in the >back. Uh, oh, COCOTs! Let me get this straight - COCOTs at Coco's? This could drive a person COCOnuts! -- Turner John Wheeler E N T E R T A I N M E N T ...!gatech!nanovx!techwood!johnw Networks Techwood Library * home of Superstation TBS * TNT * TBS Sports