What Is a Safe
Number for Guass Meters and Tri-Field Meters?
Unfortunately, a true "safe" magnetic-field exposure as of
this writing is still unclear. In fairness, this is largely
due to the inher¬ent complexities of the subject.
Researchers are still debating what they are supposed to be
measuring, because no one knows what the detrimental element
in the electromagnetic equation is. It is presumed at the
moment to be the magnetic component, since there is more
evidence pointing in that direction, but even within that
presumption questions arise. For instance, are there
particular wave forms that are more detrimental? Are the
rounded sine waves (typical by-products of electrical
transmission) all right at one level of intensity, but the
jagged sawtooth waves (typi¬cal of TVs and VDTs) hazardous
at the same intensity?
What about harmonics — the phenomenon of additional
fre¬quencies at 120 and 180 hertz that are also created by
devices and appliances that travel out from wires just like
60-hertz waves? Sometimes the harmonic wave is more dominant
than the 60-hertz wave. Some of the better gaussmeters
measure harmonics, but with varying accuracy. (The issue of
harmonics may be an important one in the future because the
180-hertz wave can actu¬ally build up on some wires,
especially around computers.)
For the consumer wanting a simple answer on safety, these
kinds of issues can seem like techno overkill, but they are
genuine concerns to those involved with fine-tuning our
knowledge. Of¬fice environments and fluorescent lights, for
instance, are rich with harmonics. Gaussmeters that do not
factor them in will not provide an accurate assessment of
exposures. (Ask the manufac¬turer if the meter you are
buying measures harmonics, but don't be surprised if you get
a complicated or evasive answer. The ques¬tion itself is
more complicated than can be explained here.) EMF office
environments can be extremely complex. It is probably best
to hire an independent firm with broad-band equipment to do
the measurements.
A simple consumer's gaussmeter that may not read harmonics
will not give you accurate information. While no one wants
to make a recommendation that turns out to be incorrect, in
general those who have examined the medi¬cal literature
recommend trying to minimize exposures to around the
1-milligauss level—knowing full well that even this may turn
out to be too high. Or that a recommended low level may be
found to fall within a dangerous window for bioeffects that
a higher level does not. This is still evolving knowledge,
but the 1-milligauss level is where the least bioeffects
have been observed; 2 milli-gauss and up are the levels at
which various detrimental associa¬tions begin to appear.
Some would say the 1-milligauss recommendation is too
ex¬treme. Others would call it a conservative educated
guess. But maintaining a 1 -milligauss level is not always
easy, or even pos¬sible, as we move through a normal day The
ambient EMF back¬ground of modern cities, according to some
estimates, is around 3 milligauss, although this varies from
area to area. (Some streets measure 0 milligauss, others are
100, depending on plumbing currents, unbalanced loads, and
peak electrical usage.) More¬over, the exposures increase
radically the higher up in altitude one gets on most city
skyscrapers. That is why it may be important to reduce as
many exposures as possible from extraneous con¬sumer
products. Anyone living or working in an ambient environment
with consistent readings above 5 milligauss will certainly
want to in¬vestigate how to reduce those exposures.
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"Revolutionary New Technologies
Protect You from the Harmful Effects of
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Click on any of the pictures below
to learn more
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