WiFi Health Scare Smackdown

In the most glaring example of junk science this side of An Inconvenient Truth, a BBC documentary series called Panorama this week claimed a wireless-enabled laptop puts out three times as much electromagnetic radiation as a cell tower. The report prompted Sir William Stewart, head of the U.K.’s Health Protection Agency, to call for an inquiry into the use of wireless Internet networks in schools because of concerns they could be exposing children to the risk of cancer. When I saw this report yesterday, I thought the notion that a laptop WiFi card could actually be pumping out the same RF power as a cell site antenna to be so ridiculous no one could take it seriously. Come on, if it were true, the moment you switched on the your laptop it would jam every wireless device in a 50-foot radius: cell phones, AM/FM radios, garage door openers, toys and so on. That level of output would also deplete your laptop battery in, oh, about ten minutes. But it goes to show how many people can be taken in by scientific sensationalism. Turns out the producers distorted the data to create a headline, the Manchester Guardian reported. (Brit spellings retained below ). They measured the RF output of the WiFi card from 3 feet away and the RF output of the cell antenna from 300 feet away.

Paddy Regan, a physicist at the University of Surrey, criticized the experiment at the heart of Panorama’s claims because the measurements of signal power had not been made at equal distances from the mobile phone mast and the Wi-Fi laptop. A spokesman for the programme told the Guardian that the “three times higher” comparison was based on measurements taken one metre away from the laptop and 100 metres away from the phone mast, although material sent to journalists promoting the programme did not make this clear. Dr Regan said: “It’s a basic fundamental of science measurement, that if you are trying to compare things you have to take into account the so-called inverse square law.” To make a fair comparison between two radiation sources the measurements should be taken at the same distance away. The levels measured by the Panorama investigation were 600 times lower than levels considered dangerous by the government. “It does sound like a scare story to me,” said Dr Regan. The programme’s evidence was criticised as “grossly unscientific” by Malcolm Sperrin, director of medical physics and clinical engineering at Royal Berkshire hospital. “It’s impossible to draw any sort of conclusion from the data as presented there.”