Last weekend, New Zealand's Dominion Post ran a scare-story, Waves of Uncertainty Over Wi-fi. Couched in the "on the one hand, but on the other hand" style of newspaper reporting, it plays off officialdom, a concerned parent and a scientist willing to go on record suggesting that technologies such as cellphones and Wi-fi expose their users to potentially risky levels of electromagnetic radiation.
Sadly, the article is a textbook example of how not to report a science story: it is unbalanced, credulous, omits key information, and allows assertions to stand unchallenged. It never reaches a firm conclusion, but ends with a list of steps for limiting your exposure to Wi-fi, with the clear take-home message that Wi-fi is a potentially significant danger.
First the basics: Wi-fi networks run on radio waves, which are the putative source of danger. Radio waves -- like infrared, visible light, ultraviolet light, x-rays and gamma rays -- are electromagnetic waves. The only fundamental difference between them is their wavelength. In 1905, Einstein showed that light arrives in discrete packets called photons, and that the shorter the wavelength, the more energy each photon carries. Radio waves have the longest wavelengths and weakest photons, while only ultraviolet, X-ray and gamma ray photons pack enough of a wallop to remove electrons from atoms or break the bonds between atoms that hold molecules together. Consequently, ultraviolet, X-ray and gamma ray photons are the ones that clearly cause damage to the DNA molecules in our bodies, leading to mutations and eventually cancer.
It is possible that weak radio waves can cause harm to biological systems -- almost anything is possible -- but no-one knows how they would do it. Some studies appear to show a correlation between cell-phone use and certain cancers, but the overall consensus is that there is no evidence of a connection between low-intensity radio waves and cancer. Moreover, the radio emission from Wi-fi networks is relatively weak: the maximum radio emission from a Wi-fi base station is set by the international standard that defines the Wi-fi "protocol") at 1 Watt, although popular models such as the Airport Extreme typically peak at just half that. How much is 1 Watt? About the same as emitted by a child's nightlight -- which is to say, not very much.
But you won't find this sort of quantitative information in the article.
"No evidence of a connection" still leaves plenty of scope for worry, apparently, and the article gets a lot of mileage out of it. In particular, it gives a good deal of space to Wi-fi activist Damon Wyman, whose 11 year old son contracted a fatal brain cancer around the time he began sleeping with a Wi-fi equipped iPad under his pillow. To quote Wyman: "We're not saying that [Wi-fi] caused it, but it seems like a bit of a coincidence" -- the suggestion, of course, being that it was no coincidence at all.
Wyman's situation is heart-rending, but a well-reported story would have gently tested the factual basis of his suspicions. The article tells us that the cancer developed within a month or two of the iPad arriving in the house. However, even the scariest studies linking wireless signals to cancer look at years of exposure in large populations in which only a small number of people become ill. You could make a child sick on a timescale of a few months by putting a decent-sized chunk of plutonium in their bedroom -- but if a wireless device used by hundreds of millions of people could do that much damage that quickly, we would know. (And as a parent, I suspect most people would be pleased to see the iPad absolved of involvement in this tragedy.)
For the science, the article quotes at length Dr Mary Redmayne, a Monash University researcher with a PhD from Victoria University Wellington. Redmayne suggests that we treat wireless technology with "kid gloves". Redmayne is dissenting from the broad scientific consensus that underpins current exposure standards, but the Dominion Post article makes no effort to critically review her claims.
Every scientist operates with a set of background assumptions – what a Bayesian calls their "priors." I am a theoretical physicist who knows a good deal about atoms and electromagnetic radiation, but I am not a biologist. Hence my focus on the physics behind this story.
By contrast, according to her VUW profile and LinkedIn page, Redmayne gained a "Certificate of Electrobiology" from the Building Biology and Ecology Institute of New Zealand in 1995, worked as a "Healthy home and electrobiology inspector" in the late 90s and was involved in advocacy around wireless exposure well before she began her PhD. The Building Biology and Ecology Institute of New Zealand's website doesn't mention a certificate in electrobiology, so we can only guess what the curriculum might have involved. However, the institute does sell booklets on electro-biology that cover "earth energies, vibrational medicine, [and] vibrational resonance", all of which are pure quackery. Likewise, this pdf on the Institute's website makes claims about dangers from artificial electromagnetic fields that are far outside the science, and hilariously suggests dowsing for harmful "earth rays". It is painfully obvious that the Building Biology and Ecology Institute is not a credible source on anything more complicated than a composting toilet (although there they would seem to be pretty much on top of their material).
A competent journalist should discover this background in minutes – seconds, if their Google-fu is strong -- but the Dominion-Post article provides no attempt to balance Redmayne's commentary, or flag it as a minority opinion. Instead, her viewpoint is presented as authoritative.
Let me be clear, Redmayne has a PhD and her papers appear in serious, peer-reviewed journals; I haven't made an attempt to critique her science, but she is clearly at one end of a range of opinion. And if she has fallen victim to confirmation bias on the question of Wi-fi and cancer, it could well be because she is primed to worry about the health-risks associated with exposure to low-level radio signals.
As for me, I can see plenty of dangers associated with giving children wireless devices, but they are of the "why don't you get up off the couch / visit a friend / go swimming / throw a ball / practice your instrument / build something / ride your bike / read a book / do what kids did when I was a kid" variety.
And if wireless does turn out to be the lead paint, asbestos or cigarettes of the 2020s, I will eat a tinfoil hat.