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For the record

Wi-Fi networks

There have been a number of recent newspaper articles and a BBC Panorama documentary about the alleged harm of radiation from Wi-Fi, or wireless communication networks, on health. The Daily Telegraph reported in April the potential dangers to children from placing computers on their laps, while an article in The Independent in June described how a “naturopath” diagnosed her patient as suffering from “overexposure to Wi-Fi and mobile phone frequencies”. The recent Panorama investigation claimed that radiation from a Wi-Fi unit in a school was three times that of a mobile phone mast 100m away, and that precautions should be taken with children who maybe more sensitive to radiation from Wi-Fi units.

You can read The Independent article here, The Daily Telegraph article here and details about the BBC Panorama programme article here.

Professor David Coggon, Environmental Epidemiologist responds:

The radio waves used in Wi-Fi are similar to those produced by mobile phones, but have a slightly different frequency (analogous to the difference between medium and long wave radio transmissions). They also differ in their exact signal characteristics. The limited evidence that has been published to date indicates that levels of exposure from use of a laptop with Wi-Fi are generally much lower than those from using a mobile phone, and that those simply from being in an area where Wi-Fi is used are even lower. However, it would be helpful to have more research on this.

There has now been a lot of research on possible health risks from mobile phones, as well as from other sources of radio waves such as television transmitters. The balance of evidence does not point to adverse effects, either in the short or the longer term. This makes it less likely that Wi-Fi poses a health hazard.

Nobody can ever guarantee that anything in life is completely safe, and inevitably there are scientific uncertainties. For example, one could speculate that there might be a hazard peculiar to the exact frequency band or signal characteristics of Wi-Fi. However, from our current understanding of the biophysics of radio waves, this seems extremely unlikely.

On electrosmog, Professor Anthony Davies, Electronic Engineer, responds:

‘Smog’ is derived from ‘Smoky fog’ and refers to a kind of polluted fog which can be actually and provably harmful, and was a real and serious problem in cities such as London in the 1950s. Using the word ‘Smog’ in the context of electromagnetic radiation is a clear attempt to bias the listener by associating almost-certainly harmless radiation with recollections of the harm caused by polluted fog in the past. If Wi-Fi signals are to be called ‘electromagnetic smog’, then for consistency, the term ‘daylight smog’ should be used to describe ordinary sunlight.

more information describing Wi-Fi:

Description of wireless communication from the Health Protection Agency

Wi-fi? Why worry? article from Bill Thompson at the BBC

Author: Sense About Science

Document type: For The Record

Published: 24 July 2007

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