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If you are worried about getting cancer from your cell phone, you
must pay attention to the SAR it emits.
SAR means “specific absorption rate.”
SAR is a measure of the rate at which radio
frequency (RF) energy is absorbed by the body when exposed to a
radio-frequency electromagnetic field. TV sets radiate RF just as
mobile phones.
Defined as the power absorbed per mass of tissue
in units of watts per kilogram, SAR computation is usually averaged
either over the whole body, or over a small sample volume (typically
1g or 10g of tissue).
SAR is used to measure exposure to fields
between 100kHz and 10GHz. It is commonly used to measure power
absorbed from mobile phones and during hospital MRI scans.
Governments have defined safety limits for
exposure to RF energy produced by mobile devices that mainly exposes
the head or a limb for the RF energy.
In the United States the FCC requires that
phones sold have an SAR level of 1.6 watts or less per kilogram
(W/kg) taken over a volume of 1 gram of tissue.
In the European Union the SAR limit is 2W/kg,
averaged over 10 grams of tissue.
For whole body exposure there is a limit of 0.08
Watt/kg averaged over the whole body.
The various cell phone makers have websites
specifically to tell the public the SAR of each of their models.
The levels of radiation cell phones emit vary
according to the brand and model.
There is a news site—CNET—that has a list of
mobile phone makes and models and their radiation.
The CNET editors, wishing to be fair to the cell
phone manufacturers, inform the public that their effort to publish
the SAR data must not be construed as a statement that cell phone
radiation causes health risks. But they are also careful to note
that their data (if they show that your particular brand and model
has a low SAR number) is safe.
Some recent studies have suggested—but mind
you the medical community has not accepted this as conclusive—that
cell phone use and high SAR are linked to some types of brain
tumors.
But the US Food and Drug Administration official
says there is not enough information to conclusively judge the
safety or hazard of cell phones.
The charts seen in the CNET website tells you
the amount of radio frequency power that is absorbed by the human
body. The trouble is we don’t know if the standard used was a huge
European body or a small Filipino one.
And doctors say that the particular geometry of
the head and which side—or which ear—is always used determines
what part of the brain is likely to develop tumors.
The SAR level found on the CNET lists shows the
highest SAR level when the phone is placed right next to the ear.
But SAR levels change, depending on what transmission bands are used
by the telecom company.
There are companies that sell products that make
sure you don’t directly get bombarded with RF.
They sell headsets and speakerphones and such
things.
Asked by Web MD (a magnificent source of medical
advice on the Internet), the American Cancer Society’s vice
president for epidemiology and surveillance research, Michael Thun
said about making cell phone use really safe:
“The first thing we say is that if someone is
concerned about the risk of cell phones, you can virtually eliminate
your exposure by using a headset or a speaker phone or having the
phone farther from your ear,” Thun tells WebMD.
“With respect to the science . . . we, and the
epidemiologists who I respect who are involved in this, find the
evidence to be much, much weaker than it’s being presented by some
proponents,” says Thun, noting that cell phone emissions are
“not ionizing radiation that damages DNA” and that of the 17
studies on cell phone use and brain cancer, only two have suggested
an association, and those studies’ methodologies are “weaker
than some of the larger, better studies.”
WebMD continues: “Thun points out that in
Sweden, one of the countries where cell phones caught on early, up
to 25 years of data show no signs of increased brain cancer rates.
He also says that the American Cancer Society is “seriously
considering” convening an independent group of scientists to look
at the epidemiologic data.
But Thun notes that cell phones are widely used
and that “the evidence is quite extensive, but incomplete in
important ways.” For instance, he says more studies are needed on
the long-term effects of children’s cell phone use.
“On the one hand, it’s important to be
prudent and have an appropriate level of caution, and on the other
hand, it’s important not to sound false alarms, because they, too,
have unintended consequences. If you sound too many of them, nobody
believes anything you say, and if there is not a problem, they
distract attention away from real problems, of which we have a lot.
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