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Portada del sitio > Prensa > Wi-fi: should we be worried?: Concern about the safety of wireless networks (...)

The Times, 11/12/06

Wi-fi: should we be worried?: Concern about the safety of wireless networks is mounting, with people blaming everything from headaches to cancer on the technology

Martes 12 de diciembre de 2006 · 9248 lecturas

The Times, 11/12/06

Wi-fi: should we be worried?
Nicki Daniels

Concern about the safety of wireless networks is mounting, with people blaming everything from headaches to cancer on the technology

It started as a low murmur, and has now risen to a persistent hum. Thanks partly to a lively correspondence in the pages of The Times, the debate about the safety of wireless networks is gathering momentum. Is this new technology a threat to human health comparable to smoking - as some campaigners claim - or an electric storm in a teacup?

Wireless networks - known as wi-fi or wLAN (wireless local area network) - are increasingly used in schools, offices and other public places to connect computers and laptops to the internet using radiofrequency transmitters with no need for complex cabling. In future, whole town centres will be transformed into wi-fi “hot spots”, enabling people to access the internet wherever they are through hand-held devices, including mobile phones. Indeed, Milton Keynes, Norwich and the borough of Islington, in North London, already have this WiMax technology.

It has taken the public a while to wake up to the idea that wireless transmitters could be less than benign. As with mobile phones, we first embrace the liberating new technology and only later ask the awkward questions. Perhaps, as with pharmaceuticals, the order should be reversed. The official line on the health implications of wi-fi is that exposure to low level electromagnetic radiation from wireless networks is well below recommended levels and that there is no evidence of risk. But despite these soothing words, the groundswell of concern is mounting, with some people blaming everything from headaches to cancer on exposure to radio-frequency fields.

As reported in this newspaper, a number of schools have dismantled their wireless networks after lobbying from worried parents, and others are under pressure to follow suit. In Austria the public health department of Salzburg has advised schools and kindergartens not to use wLAN or cordless phones. Lakehead University in Ontario, Canada, which has 7,400 students, has removed wi-fi because of what its Vice-Chancellor, Dr Fred Gilbert, calls “the weight of evidence demonstrating behavioural effects and physiological impacts at the tissue, cellular and cell level”.

Some experts have also expressed concerns. In September, 30 scientists from all over the world signed a resolution calling for a “full and independent review of the scientific evidence that points to hazards from current electromagnetic field exposure conditions worldwide.” Closer to home, the Irish Doctors Environmental Association (IDEA) has asked its country’s Government to carry out “a full assessment of the health impacts of electromagnetic radiation”.

“There has been no research specifically looking at the effects of wireless networks on human health,” admits Alasdair Philips, the scientific and technical director of the lobby group Powerwatch. “But I have seen enough anecdotal material to be convinced that some people are affected by them.”

David Dean, 43, a councillor in Merton, South London, and the managing director of a publishing company, describes himself as a human antenna. “The moment I go into people’s houses I know whether they have wi-fi because my head starts to buzz. I had to leave my last job because I couldn’t stand up for more than ten minutes in the office and my boss would not remove the wi-fi. My heart raced, I had double vision and really bad headaches. It felt as though my head was in an arm lock. Twice I have been into homes where the children were screaming monsters. After I suggested to the parents that they turn off the network for two days, the kids were transformed.”

Anxiety about wi-fi has focused on the effect of electromagnetic radiation on children because they have thinner skulls, less fully developed nervous systems and will undergo a lifetime of exposure to cellphone technology. In his report on mobile phones, Professor Sir William Stewart, the chairman of the Health Protection Agency (HPA), acknowledged that radiation below guideline levels, while thought to be safe, may have effects on the body. He therefore advocated a precautionary approach, including close monitoring of radiation from masts near schools and a recommendation that the beam of greatest intensity from a mast should not fall within the grounds of a school.

“The emissions from wireless networks are very similar to those from mobile phone base stations in terms of frequency and signal modulation,” says Philips, who, it must be said, runs a company selling electromagnetic radiation detectors and blockers. “Many published reports have shown ill-health affects apparently associated with living and working close to mobile phone masts. In a Latvian study of 966 children, motor function, memory and attention were significantly worse in the group exposed to radiation from a pulsed radio location station. The exposure levels were low, but similar to those that children in classes with wLANs will be exposed to.”

Dr Michael Clark, of the HPA, says published research on mobile phones and masts does not add up to an indictment of wi-fi. “All the expert reviews done here and abroad indicate that there is unlikely to be a health risk from wireless networks,” he says. “The few studies on mobile phone masts that have appeared in peer-reviewed journals claiming to observe health effects are not at all conclusive. The real problem is deciding what level of precaution is appropriate.

“When we have conducted measurements in schools, typical exposures from wi-fi are around 20 millionths of the international guideline levels of exposure to radiation. As a comparison, a child on a mobile phone receives up to 50 per cent of guideline levels. So a year sitting in a classroom near a wireless network is roughly equivalent to 20 minutes on a mobile. If wi-fi should be taken out of schools, then the mobile phone network should be shut down, too - and FM radio and TV, as the strength of their signals is similar to that from wi-fi in classrooms.”

Philips is not reassured: “Electromagnetic radiation exposure guidelines in the UK are designed to protect against gross heating effects. They are not meant to protect against long-term exposure to low levels of pulsing microwaves, such as laptops emit when downloading. We believe that these interfere with the body’s own normal internal electrical and electro-chemical signalling systems, leading to serious health problems, and growing children may be more affected than adults, whose cells are not changing as rapidly.”

One of the problems in conducting research is that not everybody is affected by electromagnetic radiation in the same way. “A growing, consistent body of literature demonstrates that a subgroup of the population appears to suffer distressing symptoms when exposed to this type of radiation,” says Dr Elizabeth Cullen, of IDEA. Sleep disturbances, depression, blurred vision, heart and breathing problems, nausea and headache are among the most common symptoms.

Up to 5 per cent of the population is thought to have this sensitivity, which is recognised in Sweden as a disability. In Stockholm sufferers can have their homes adapted to remove or screen out sources of electromagnetic radiation. If this proves ineffective, they can even rent council-owned cottages in areas of low radiation.

However, Dr Clark is not persuaded that electromagnetic fields are the cause of sensitivity. “While we accept that some people experience genuine symptoms, which can be distressing, what causes them is another matter. Most scientists are very sceptical because of the published laboratory investigations of electrosensitivity. People who are convinced that they can tell when they are in the presence of electromagnetic radiation cannot detect the fields in double-blind laboratory conditions.”

An important study by the University of Essex, due to be published next year in a peer-reviewed journal, may settle the matter. During the trial, 55 people who believe that they are hypersensitive and 120 non-sensitive controls were subjected to tests of concentration and memory while signals from second and third generation mobile phone masts were switched on and off. The trial was double blind: neither the researchers nor the subjects knew when the signals were firing.

Some believe that sensitivity symptoms are not the only threat posed by electromagnetic radiation. A Swedish study suggests that there is an increased risk of acoustic neuroma (an auditory nerve cancer) in people who have used mobile phones for more than ten years. Conversely, last week the results of the largest and longest-running study on mobile phones and the risk of cancer, published in the Journal of the National Cancer Institute, found that there was no link.

A literature review conducted by the International Commission for Non-Ionising Radiation Protection concluded: “Results of epidemiologic studies to date give no consistent or convincing evidence of a causal relation between exposure from radio frequency fields (RFs) and any adverse health effect. On the other hand, these studies have too many deficiencies to rule out an association. Despite the ubiquity of new technologies using radio frequency fields, little is known about population exposure from RF sources, and even less about the relative importance of different sources.”

And here lies the nub of the problem. Not enough research has been done over long enough periods on the effects of various levels of exposure on different populations to draw any firm conclusions about the dangers, if any, of wireless networks. As to whether the convenience is worth the risk - only you can decide.


“Electrosensitivity” is a rather misleading term. I’m fine around electricity. But put me next to a BlackBerry or a wireless laptop accessing the internet and I feel dizzy, slightly nauseous and my flesh tingles as if it’s being scrambled. It sounds bonkers I know. But after years of denial I have had to come to terms with the fact that aspects of this fantastic new technology do not agree with me.

We installed wi-fi in our house two years ago. We loved it. The whole family could be online at the same time. I imagined myself working in the garden during the summer (although I never did), and I could work in bed. But from the moment wi-fi arrived I felt peculiar.

I mentioned casually to my husband that I could tell when he was sending an e-mail, but he dismissed that as laughable: I must be imagining it. So I put the idea out of my mind. But as the weeks and months passed I began to feel iller, overwhelmed at times by intense giddiness, headaches and a sense that I was moving through a dense fog. Sleep was fitful and I seemed to feel constantly at a low par.

Then we went away for the Easter break to stay with friends in the depths of remote countryside. I felt great as you tend to do when you’re on holiday. But the moment we walked back into our house I felt giddy and nauseous again and then I knew. I wasn’t neurotic. This was real.

I changed our router back to wired internet access. I had the computers reconfigured so that they no longer sent out signals searching for wi-fi and we binned the dect phones (digital cordless phones) just to make doubly sure. My husband began to notice the change in me within days and, finally, he believed me.

The trouble is that you can’t talk about this without people thinking that you’re mad. My symptoms are minor compared to others I have heard of. Sometimes I notice wi-fi in the wider world when it’s heavy - my local bookshop, the Apple Mac shop, airports and an expensive hotel we recently went to stay in. Other times I feel this scrambled fog only when I’m near a device using this technology - the hand-held machine in restaurants that you tap your pin number into and laptops surfing the web.

After months of monitoring, I’m happy knowing that it is wi-fi that makes me feel this odd and not some other unknown disease. I avoid it when I can. I don’t see much difference between someone smoking a cigarette or shouting into a mobile phone next to me in a public place. If anything I think I’d prefer the cigarette.

Poppy Rhodes

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