Fears about the safety of mobile phones are overdone

AT THE height of the cold war, one of the most powerful radar stations in the world flooded the Soviet Union with a river of microwave radiation from a huge antenna array at Orford Ness on the Suffolk coast of Britain. Bouncing off the ionosphere, the “over-the-horizon” radar swept across eastern Europe to Plesetsk and beyond in the heart of Russia. It was designed to provide early warning of any Soviet bombers or ballistic missiles being launched against the West.



The radar's 10-megawatt transmitter—20 times more powerful than the mightiest civilian broadcasting stations of the day—was powered by electricity from the nearby Sizewell nuclear power station. When testing started in 1971, local sailors were quietly warned not to enter a designated zone where the microwave energy rippled out across the North Sea. Heat from the beam, they were informed, “would fry their eyeballs”.



The British authorities never admitted whether the restriction was for the sailors' protection, or merely to keep prying eyes away from a sensitive site. There is no doubt, though, that, close up, a 10-megawatt microwave beam would scramble an egg. Microwave ovens use a mere kilowatt to do that and more. The point of the anecdote is that the only physical effect radio waves have on living tissue—whether at the 4-40-megahertz part of the spectrum deployed at Orford Ness or in the 450-2,700-megahertz bands used by mobile phones—is to increase the surface temperature.



No matter how powerful the transmitter, radio waves simply cannot produce ionising radiation. Only gamma rays, X-rays and extreme ultra-violet waves, which operate in the far (ie, high-frequency) end of the electromagnetic spectrum, along with fission fragments and other particles from within an atom, and cosmic rays (those particles' equivalents from outer space) are energetic enough to knock electrons off other atoms to break chemical bonds and produce dangerous molecules called free radicals. It is these highly reactive free radicals that damage a person's DNA, causing mutation, radiation sickness, cancer and death, depending on the dose.



By contrast, at their much lower frequencies, radio waves do not carry anywhere near enough energy to produce free radicals. The “quanta” of energy (ie, photons) carried by radio waves in, say, the UHF band used by television, Wi-Fi, Bluetooth, cordless phones, mobile phones, microwave ovens, garage remotes and many other household devices have energy levels of a few millionths of an electron-volt. That is roughly a million times too weak to cause ionisation. To produce free radicals, photons need to pack at least a couple of electron-volts of energy.



All of which leaves your correspondent a little puzzled as to why the World Health Organisation should recently have reversed itself on the hazard that mobile phones pose to people's health. Late last month, the organisation's International Agency for Research on Cancer (IARC) decided to classify radio-frequency electromagnetic fields (ie, radio waves) as “a possible carcinogenic to humans” based on a perceived risk of glioma, a malignant type of brain cancer.



In May 2010, following a landmark, decade-long study undertaken by teams in 13 countries, the IARC reported that no adverse health effects could be associated with the use of mobile phones. Indeed, the group went so far as to highlight the biggest risk to mobile-phone users as being, not brain cancer, but road-traffic injuries caused by talking while driving. As for the heating effects of radio waves, the increase in temperature of the skin caused by holding a mobile phone close to the ear was found to be an order of magnitude less than that caused by being exposed to direct sunlight.



The Group 2B classification the IARC has now adopted for mobile phones refers to “possible”, not “probable” (Group 2A) nor “proven” (Group 1), carcinogens—and ranks the mobile phone's health risk alongside the chance of getting cancer from coffee, petrol fumes and surgical implants such as stents and false teeth. In other words, pretty small and, even if such effects were ever detected, nothing to get hysterical about.



That has not stopped the tinfoil-hat brigade from continuing to believe that deadly waves in the ether are frying their brains. Lately, the paranoia has focused on smart electricity meters. Such meters interrogate various appliances within the home and relay wireless messages continuously to the power company about the household's pattern of electricity use. Such real-time information allows the company to manage its generating capacity more intelligently. In so doing, it can pass some of the benefits back to customers who let it adjust their heating or air-conditioning remotely at certain times of the day.



Lately, a backlash among homeowners in northern California, who fear they are about to be drenched in dangerous radio waves, has forced a handful of municipalities to slap moratoriums on the smart meters being introduced by Pacific Gas & Electric. The California Public Utilities Commission has rightly ignored such silliness. But it intends to give customers the option of keeping their old meters, though the utility will be allowed to charge them for sending someone out to read their dumb analogue meter every month.

Actually, smart meters are just about the last thing to worry about. In an independent study released last April, the California Council on Science and Technology, an advisory arm of the state legislature, concluded that wireless smart meters, when installed and properly maintained, produce much lower levels of radio-frequency exposure than many existing household devices, especially microwave ovens and mobile phones. The council, comprising dozens of the state's most eminent scientists, engineers and scholars, noted that, to date, it had not been possible to identify or confirm any health problems resulting from potential non-thermal effects of radio waves (should such effects exist). But nor had it been possible to show categorically that there weren't any.



The latter is next to impossible. Indeed, by classifying mobile phones as a Group 2B risk, what the IARC was effectively saying (and the California Council on Science and Technology implying) was that, even if such a health risk exists, there is no way of ruling out bias, chance or other confounding circumstance with any reasonable degree of confidence. So, to hedge bets, protect careers and guarantee future funding, the obvious thing to suggest is yet more research on the long-term, heavy use of mobile phones. The most likely result, given the nature of the problem, is that the conclusion will be equally inconclusive.



And equally irrelevant. The Twitter generation already texts rather than talks. Adults are catching up fast. According to Nielsen, a media-research company, the number of text messages sent and received by people aged 45 to 54 years of age rose 75% during a three-month period when measurements were made last year. Over the same period, the number of phone calls adults made and received fell 25%. Meanwhile, for those who insist on yakking, hands-free is fast becoming the norm, thanks to stiffer penalties for using handsets while driving and the proliferation of talking gadgets.



As readers have no doubt gathered, your correspondent thinks the whole brouhaha over mobile phones causing brain cancer is monumentally irrelevant compared with all the other things there are to worry about. He is more concerned about irresponsible scofflaws rear-ending him while they are texting or talking on the phone—and causing serious injury to himself and his family, as well as themselves. Regretfully, that is far more likely to happen than anything so bizarre as to fall victim of some inexplicable form of radio-induced glioma.