Today we're going to point the skeptical eye at popular claims that ordinary radios — such as walkie talkies, police and emergency radios, and those embedded in devices such as cell phones, wi-fi hubs, and smart utility meters — are dangerous. Some say they cause cancer, some say they present other more nebulous health risks. How concerned do you need to be that something as ubiquitous as radio could be doing you more harm than good?
This issue rose to the headlines in popular media with a frightening announcement in May of 2011 by the World Health Organization. The press release stated that the International Agency for Research on Cancer (IARC) had placed radiofrequency (RF) in their Group 2B of possible carcinogens due to an increased risk of the brain cancer glioma associated with the use of mobile phones. Unfortunately, very few people actually read the release, and saw only that headline, which presents a highly skewed perspective of what was actually said. As a result, new movements arose worldwide, notably in Canada, for certain RF devices to be banned. Canada's Green party openly called for the elimination of wi-fi computer networks in schools, and many groups have campaigned against the purported health effects of smart meters (like this and this).
My question to the groups actively campaigning against stuff that's in Group 2B is "Do you drink coffee?" Most do, and yet coffee is also in Group 2B. So are the crafts of carpentry and joinery. Pickled vegetables, coconut oil, and even the Earth's magnetic field are in Group 2B. Now, granted, it would be fallacious logic to say that just because these other things sound ordinary and safe, that makes radiofrequency safe; but it is true that the World Health Organization considers them to be similarly risky.
Group 1 is the classification for things that have been found to be carcinogenic. This includes ultraviolet radiation, tobacco, and plutonium.
Group 2A is the classification for probable carcinogens, things that have not yet been found to cause cancer but for which there is good evidence they might. This includes engine exhaust and working in the petroleum industry.
Group 2B is the list of possible carcinogens, which are things that have not been found to cause cancer but for which there is cause to study further. It is a list of items which have not — repeat, not — been found to be carcinogenic. Will they tomorrow? Maybe, but they're not now, according to what we know so far.
If the World Health Organization is the authority whose word you're going on, then you should look at what they actually say. Their position paper on radio frequencies and electromagnetic radiation states unequivocally that:
...Current evidence does not confirm the existence of any health consequences from exposure to low level electromagnetic fields.
Nor should we expect such consequences. Radiofrequency is all around us, and always has been. Tune any radio to a station containing static and what you're hearing is normal background radiation. About 1% of that static is actually left over from the Big Bang. But just because radiofrequency is natural for all living beings throughout the universe, that doesn't mean it's safe. To determine whether something is safe, we look at the data. So let's look at what we know so far.
The electromagnetic spectrum is pretty simple to understand. It starts at the low end with a frequency of zero, up through the radio frequencies, past visible light and up through gamma rays and onto infinity, with higher and higher frequencies. The frequencies at the lower end are what we call non-ionizing, because they lack sufficient energy to strip electrons and change chemistry. The frequencies at the higher end are ionizing, which makes it damaging to living tissue. The dividing line between the two is the upper end of visible light, where ultraviolet begins. A sunburn is actually tissue damage caused by ionizing radiation; that UV has enough energy to just barely penetrate the outer layer of your skin. But as we go even higher, into the X-ray range, the radiation is energetic enough to penetrate all the way through your body. X-rays can be stopped by the lead-lined blanket they give you. But even higher energy frequencies, like the strongest cosmic rays, can go all the way through the entire planet.
So remember that dividing line. Visible light, like that inside your home, is generally safe as are all the radio frequencies below it. Ultraviolet light, and everything higher, is damaging.
Yet claims persist of harm from non-ionizing radiation, and they'll often cite studies showing a biological effect from some manifestation of radio. There are only a handful of such studies which are repeatedly cited, in comparison to the more than 25,000 studies surveyed by the WHO that found no reason for concern.
Perhaps the most vocal of all the anti-radio activists is Dr. Magda Havas at Trent University in Ontario, Canada. You'll be hard pressed to find a mass media article about the safety of radio devices that doesn't cite Dr. Havas as its expert. She hasn't published any good research of her own, rather she tirelessly cites these few fringe studies over and over again to promote the idea that radio is harmful. To find such studies, you have to dig past hundreds of studies that contradict her desired results. It's hard to imagine that Dr. Havas is unaware that she's promoting science that's in direct conflict with what virtually everyone else has found. You have to wonder whether her students accept her claims at face value, or whether they view it within the context of the scientific consensus.
Dr. Havas cites one such study that she says showed mobile phone signals break down the blood brain barrier. In fact, this study was a single in-vitro (petri dish) experiment, and the authors only hypothesized that one potential effect might be to increase the blood brain barrier permeability. In other words, nobody has ever observed such an effect.
Another study is often cited as showing that non-ionizing microwaves have been found to cause single and double strand DNA breakage. While this study was interesting, it was very small — only four groups of rats —and has not been replicated by any other researchers. In addition, it exposed the rats to a type of signal not found in either nature or in electronic devices (a powerful, continuous 2.5 GHz tone) and the effects disappeared when the signal was augmented with background noise. The lead author, Dr. Henry Lai, is the co-editor of Electromagnetic Biology and Medicine, a journal dedicated to the promotion of alleged biological harm from radio.
The third study the anti-radio activists promote most often is said to show that radio signals increase blood sugar, leading to diabetes. If you're wondering why so many of us live in a radio-soaked world but don't have diabetes yet, the answer lies in the quality of this study. It was Magda Havas' own research, in which she published the self-reported results of four people who identified as being both diabetic and "electrosensitive", and who said they felt better after moving away from their electronic devices. The study has essentially zero scientific validity. What was the only journal that published her article? Dr. Lai's Electromagnetic Biology and Medicine.
The sad thing is these researchers missed the boat, because non-ionizing radiation does have at least one real effect on living tissue: heat. This is why you feel warm in sunlight; the sun's gargantuan output completely blows away all the other sources we're exposed to, either manmade or natural. When electromagnetic radiation strikes an absorbent surface, like your skin, that energy is converted into heat. Simple thermodynamics.
If you aim a laser pointer at your hand, you won't feel anything. Some of the energy of that light reflects from the visible spot that we see, and some of it is absorbed by your hand and converted into heat, but there's not nearly enough heat for your nervous system to detect. But crank up the power to that of an industrial laser, and it could burn a hole right through your skin. Turn it back down to the power of a medical laser and it can excise a mole or make a precision cut. This is tissue damage from non-ionizing radiation. The mechanism is simply heat.
There are other medical applications for RF-generated heat at frequencies below that of visible light. RF is also used in dermatology and arthroscopic surgery. The basic idea here is to cook and shrink collagen fibers. This can be used to tighten skin to reduce wrinkles, to shrink ligaments and pull loose joints tight, and to ablate surfaces for cleaning up joints or attacking tumors. Radiofrequency probes are used in arthroscopic surgery, and although they're quite different from a microwave oven, they work on the same principle; but with a far lower wattage (up to about 30W), and much lower frequency (about 6 MHz). Since these radio frequencies do not penetrate the body to any degree, the probe is placed in direct contact with the ligament. The rapidly oscillating RF field twists the water molecules back and forth, and the surface is heated by the friction, called the dielectric heating effect. This temperature gets as high as about 150°F/65°C. In dermatology the wand is applied to the wrinkled skin and performs similar heating, which would be quite painful and so the wand simultaneously applies a coolant. In a monopolar surgical probe, the heating effect is extremely localized and is limited to the surface in contact with the probe; and in a bipolar probe, the field oscillates between two closely spaced electrodes, and the heating is limited to that small space.
Discounting the heat from the battery or power supply circuitry, why don't we feel any radiated heat from a wi-fi hub or a smart meter, or any other familiar radio transmitter? It's because there's not nearly enough power and it's not highly focused like a laser. Television's Mythbusters once tested this myth by strapping an uncooked turkey to a ship's high-powered radar antenna and found no measurable heating, just as we'd expect.
One day the science might change and we might learn that there actually is credible cause for concern about radio frequencies. Until it does, enjoy the services that radio provides; and don't forget to try that thing with listening to a static channel on the radio. It's really cool when you understand what you're listening to.
Cite this article:
Dunning, B. "Wi-Fi, Smart Meters, and Other Radio Bogeymen." Skeptoid Podcast. Skeptoid Media,
30 Aug 2011. Web.
9 Feb 2016. <http://skeptoid.com/episodes/4273>
References & Further Reading
ASDS. "Technology report: Monopolar radiofrequency." American Society for Dermatologic Surgery. American Society for Dermatologic Surgery, 1 Jan. 2010. Web. 12 Aug. 2011. <http://www.asds.net/TechnologyReportMonopolarRadiofrequency.aspx>
Hecht, P., Hayashi, K., Cooley, A., Lu, Y., Fanton, G., Thabit, G., Markel, M. "The Thermal Effect of Monopolar Radiofrequency Energy on the Properties of Joint Capsule." American Journal of Sports Medicine. 1 Nov. 1998, Volume 26, Number 6: 808-814.
IARC. Agents Classified by the IARC Monographs. Lyon: World Health Organization, 2011.
IARC. "IARC Classifies Radiofrequency Electromagnetic Fields as Possibly Carcinogenic to Humans." International Agency for Research on Cancer. World Health Organization, 31 May 2011. Web. 15 Aug. 2011. <http://www.iarc.fr/en/media-centre/pr/2011/pdfs/pr208_E.pdf>
Novella, S. "CFLs, Dirty Electricity and Bad Science." Science-Based Medicine. New England Skeptical Society, 22 Sep. 2010. Web. 15 Aug. 2011. <http://www.sciencebasedmedicine.org/index.php/cfls-dirty-electricity-and-bad-science/>
Shermer, M. "Can You Hear Me Now? The Truth about Cell Phones and Cancer: Physics shows that cell phones cannot cause cancer." Scientific American. 4 Oct. 2010, Volume 303, Number 4: 98.