Claire Heald
BBC
Wednesday, December 13, 2006
Some schools are removing wi-fi networks after complaints from
parents that their children suffer headaches. In what sounds like
a re-run of mobile phone radiation panic, is there evidence for
harm?
Sitting too close to the TV. Standing in front of the microwave.
Spending too long on the mobile. Living under a pylon, or next
to a phone mast. We've always worried about what the technology
around us might do to our bodies.
Now, wi-fi is rolling out from the humble coffee shop hotspot
to create swathes of wireless networks in towns and cities.
But some are concerned that we don't know enough about the health
effects of electromagnetic radiation - the radio waves that allow
the computer network to transmit (along with longwave, FM and
TV and phone frequencies).
For others, headaches and skin rashes - that they feel are due
to the radio waves - are prompting a big switch off.
The worry for parents is that children, who have thinner skulls
and developing systems, are exposed to more gadgets and gizmos than
previous generations. What might these be doing to their bodies?
Health expert advice is to limit mobile phone use among young
people as a precaution. The government advises users to keep calls
short.
Engineer Anthony Wood, a father with two young children from
Bristol, refuses to install a wi-fi network to link his family's
three home computers.
"I don't like the idea of transmitting a microwave into
your brain. The frequency is important, not just the power. The
higher the frequency, the more energy there is in the waves. I
think wi-fi waves are close to microwaves, yet they're on all
the time.
"I see no evidence to suggest they could be harmful, but
it takes an enormous amount of evidence to prove anything. I don't
understand the medical side very well but I do understand the
technical side - that of frequency and power. That's why I decided
against installing a wireless network."
Learning tool
Teachers have also raised concerns. A staff member who develops
shocking headaches after a day in the classroom may be a cliche.
But this is what happened to Michael Bevington, a classics teacher
at top independent school Stowe, in Buckinghamshire, after wi-fi
was installed in his classroom.
"I had thought, 'great, we can make use of it'. But then
I started getting a series of headaches that got worse over the
next few days."
Pains in the joints, heart palpitations and nausea followed, and
he could tell if the wi-fi transmitters were on or off.
Like a number of other schools, Stowe has turned off some of
its transmitters. But Mr Bevington says he is now sensitive to
other sources of electro-magnetic radiation, such as phones, microwaves
and fluorescent lights. He also has problems with city centre
hotspots and his neighbours' wi-fi networks.
"The amount of microwave radiation in society needs to be
completely reviewed. It's making it impossible for a small number
of people," he says.
Hot spots
Other than anecdotal, what is the evidence to suggest a risk?
There is no scientific proof that wi-fi can cause harm. But there
is also a lack of research.
Experimental psychologist Dr Stacy Eltiti, of the University
of Essex, researches sensitivity to telephone masts. The 3G signal
is transmitted at a frequency not far off that of wi-fi at about
2.4 gigahertz. Hence her results, due in 2007, may hold some clues
to wi-fi sensitivity as well.
"Everyone is exposed to mobile phone masts," she says.
"You can opt not to own a computer or a mobile phone, but
you go into your local town centre and they're everywhere. If
there are physical impacts, we can investigate what these are."
The current official advice is that exposure to wi-fi radio waves
is comparatively low.
"In classrooms, a typical exposure is at 20 millionths of
the guideline levels, whereas a mobile phone is 50% of guidelines,"
says Dr Michael Clark, science spokesman for the Health Protection
Agency.
"Twenty minutes on a mobile phone call is equivalent to
a year in that classroom. It's a completely different level of
exposure. These are non-ionising radio waves. They're not X-rays,
or gamma rays, or ultra violet. It's completely different in energy
terms. I'm looking outside now and that's electromagnetic radiation
- visible light. Radio energies are a million times less energetic
than ultraviolet light."
But as people claim sensitivity to radio waves, he would welcome
more research, given the rapid introduction of the new technology.
But currently, the more common concerns for users lie in wi-fi's
cost, patchy coverage and network security.
As Peter Green, a senior lecturer at the University of Manchester
says: "You wouldn't put your wi-fi right next to your bed,
but I know more people who are turning it off because they are
worried about security and other people hacking into their network."
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