As I promised when I entered the #IfIHadGlass competition to become a Glass Explorer, I have been testing my Google Glass Explorer Edition for emissions of electromagnetic radiation (EMR, also known as electromagnetic fields, or EMF).
My #IfIHadGlass Entry Tweet
I’ve been posting some of the measurements. I plan to continue doing so. (Follow me on Twitter or Google+for continued updates on measurements.)
What does a reading like 386.2 milliwatts per meter-square, a very high spike in radiation that I measured while streaming CNN video, actually mean about my risk?
But, predictably, the question I get a lot in response is: well, what do those measurements mean?
And that’s entirely natural, because most of us have never heard of a power density meter, don’t understand what SAR is, and really have no idea what electromagnetic radiation is, or what science can tell us about the results of exposure to EMR.
So answering that question is a longer-term discussion. With this post, I’m going to try to provide a way of framing and considering the risk presented by the measurements I am posting, as clearly and concisely as I can.
To do so, I will respond to four questions:
- How are cell phone radiation exposures measured?
- What are the risks of cell phones?
- How do EMF emissions from Glass compare to cell phones?
- What is the relative risk of using technology like Google Glass compared to an iPhone?
How are Cell Phone Radiation Exposures Measured?
People are increasingly familiar with the scientific measurement called SAR, though few understand what it is, or how it is used in regulations.
Apple’s iPhone 5 SAR Data
SAR (which stands for Specific Absorption Rate) is a measurement of the rate at which electromagnetic radiation energy is absorbed by something (generally, human tissue). So, when you hear that an iPhone 5 has a SAR of 1.18 watts per kilogram of tissue (W/kg), that is a measurement of how much radiation is absorbed by the human head — which correlates to, but is not, the actual EMF emitted by the iPhone itself. So, to be clear, SAR is a measurement of rate of absorption, not emission. (Whereas the power density measurements I am posting are gauges of field strength, not absorption.)
Now, when you hear that an iPhone has a SAR of 1.18 W/kg, it is tempting to think of the EMF emissions from an iPhone as being steady. However, this is not how wireless technology works, and it is not how SAR is utilized by regulators. If you measure EMF emissions from a device like an iPhone or Glass, you will note that the actual radiation levels vary widely, depending on the specific usage context (how, where, when & for what purposes the device is being used). However, while actual emissions vary widely and unpredictably, regulators have established a regimen by which a single SAR value is established for these devices.
(Since so many of you reading this will likely have an iPhone, it is worth noting that the iPhone 5’s official SAR value is premised on holding the iPhone 1/8” away from your body. In fact, Apple’s documentation reads: “Carry iPhone at least 10mm away from your body to ensure exposure levels remain at or below the as-tested levels.”)
A SAR Testing Dummy Used by the Swiss Office of Public Health
Official SAR values for devices like cell phones are determined in a lab, by holding a cell phone up to a dummy head, in several predetermined locations. The lab measures the various levels of radiation absorption in the dummy head. At the end of the experiment, the peak level of radiation absorption is determined, and that becomes the official SAR value for the device.
In other words, the official SAR value of an iPhone 5 tells you what the peak level of radiation absorption was, in the lab dummy, under the precise conditions on the day, time and location that the phone was tested. If you hold the phone in any different manner than it was held against the dummy, the exposure will be different. If you are further from the cell tower than the phone in the lab test, the radiation emitted by the phone will likely be higher than in the test, as more power is used to communicate over longer distances. If you are using your phone in your car or on a train, the emissions will likely be higher, as more power is used as your phone continually seeks new cell towers to relay your call.
I guess the simplest way of stating it is this: The official SAR value of a cell phone is the peak level of radiation absorption measured under arbitrary circumstances that will almost certainly NOT match real life usage conditions.
So, official SAR values may present some sort of useful benchmark for the radiation emissions of different cell phone models, but do not fool yourself into thinking that official SAR values are “accurate”, that your digital devices emit consistent levels of EMF, or that your exposure is actually knowable, unless you take measurements yourself.
What are the Risks of Cell Phones?
Well, first, it is important to reiterate that, because of varying levels of radiation and exposure, there is no way to know what your exposures are (and thus, what your actual risk might be), just from saying “I use my iPhone to make calls for an hour a day.”
X-rays submitted by David Reynard in his 1992 lawsuit against Motorola. Reynard claimed that these x-rays demonstrate that his wife’s fatal tumor matched the size & location of her cell phone. Within eight days of Mr. Reynard showing these x-rays on ‘Larry King Live’, shares of Motorola had plunged by over 20%. Mr. Reynard’s lawsuit was dismissed in 1995 for insufficient evidence.
As well, individuals respond individually to doses of EMF radiation. Some individuals are known as electrohypersensitive (EHS), and are particularly responsive to even extremely low doses. Other individuals have very healthy systems capable of repairing the damage that results from EMF exposures. And there is a wide spectrum in between. So outcomes will vary not only based on varying exposures, but also the health and well being of the individuals exposed.
It is also important to note that some of the most concerning health outcomes that are linked to cell phone radiation exposure (such as brain tumors) can take decades to form. Just because you’ve used a cell phone for 10 years now without developing a tumor, doesn’t mean you won’t in another 10 years, even if you never touch another cell phone. Neither does it mean you will. It’s just how disease works. While doses of some forms of electromagnetic energy (such as gamma rays) can kill you almost instantly, the types of health effects linked to cell phone radiation generally take much longer to manifest.
Still, the known science can help inform your understanding of the risks associated with cell phone usage. (And there is a lot of it. It is not the purpose of this post to review the vast body of science in this arena. If you are interested in learning more, I would encourage you to download and read the BioInitiative Report. It is a peer-reviewed publication from an international group of scientists that surveys thousands of scientific studies on the bioeffects of EMF exposure.)
Dr. Lennart Hardell is professor in oncology and cancer epidemiology at the University Hospital in Orebro, Sweden.
For the purposes of this post, let’s look at a single study, published in 2007 by a group including Dr. Lennart Hardell that examined the incidence of malignant brain tumors among thousands of individuals. This study is among the first epidemiological studies on this question, following such a large number of subjects over an extended evaluation period.
Hardell and the researchers found that, not only does cell phone use increase the risk of forming malignant brain tumors, but that the risk increased with latency time (i.e., how much time had passed since the cell phone exposure) and cumulative use.
The published results include a fair bit of data. I have extracted this portion (from Table 4 in the published results) to demonstrate the dose-response relationship between cell phone exposures and the risk of forming malignant brain tumors, over different time frames.
| Risk (OR) of Forming Malignant Brain Tumor Compared to “Unexposed” Population (Who Do Not Use Cell or Cordless Phones) |
| Cumulative Hours on Digital Cell Phone | 1-5 Yrs Later | 5-10 Yrs Later | 10+ Yrs Later |
| 1-1,000 | 120% | 120% | 200% |
| 1,001 – 2,000 | 160% | 150% | 200% |
| 2,000 + | 80% | 160% | 640% |
It’s worth noting this is time spent speaking on the phone, not browsing the web or sending text messages. So this refers to doses of radio frequency and microwave radiation from cell phones to the brain. And the data reveals increased risk from supposedly “safe” doses, but that the risk increases both with the dose, and the amount of time that passes.
So, while I can not actually answer the question “what are the risks of cell phone use” (brain tumors are but one class of the bioeffects that are documented to result from exposures to cell phone radiation), I have included this one study to note that high-quality peer-reviewed science has identified such risks, and that such risks are demonstrated to increase in a dose-response relationship. The known body of science on the subject of human exposure to cell phone radiation has reached the point where the World Health Organization has identified radio frequency EMF as a Class 2B Carcinogen. Another indicator that this risk is real: a leading Lloyd’s of London underwriter has, since 1999, refused to issue policies to cover cell phone manufacturer’sagainst claims of harm of their consumers’ health.
The more you use the tech, the greater your cumulative exposure; the greater your cumulative exposure, the greater the risk of forming malignant brain tumors. And the risk continues to increase with time, even if your cumulative use remains unchanged!
Before moving on, you may ask, “Those are some terrifying numbers! Why don’t I see more of my friends with brain tumors?” To that, I would remind you these types of bioeffects take many years or decades to form, and we have only recently reached the point where large numbers of people have been using cell phones for over a decade (I got my first Nokia in 1999). As well, we are discussing small affected populations to begin with. Doubling, tripling or even sextupling the number of individuals who develop malignant brain tumors, will still result in a relatively small number of people.
How do EMF Emissions from Glass Compare to Cell Phones?
Now that we have at least some sort of crude gauge for the risk of cell phone use, the obvious next question is, how does the EMF from Glass compare to that from a cell phone?
There are different ways of answering that question.
SAR Measurements from the Leaked FCC Filing for Google Glass
Let’s start with SAR. According to Google, Glass has an official SAR value of 1.11 W/kg. That places it at the higher end of EMF emissions, compared to cell phones on the market today, but still within FCC limits of 1.6 W/kg. So, per their official SAR values, Glass emits roughly equivalent (though slightly less) EMF radiation than an iPhone 5.
Using SAR as the only metric, however, obscures a key distinction between technology like Glass and cell phones: they utilize different technologies for communication. Cell phones use cell phone frequencies (3G, 4G, etc.). Glass uses WiFi and Bluetooth. Both WiFi and Bluetooth contain more energy (i.e., operate at higher frequencies) than cell phone data.
(Yes, it is true that today many cell phones also have WiFi and Bluetooth. But, when the cell phone is held directly against the head, generally the dominant data connection is the cell phone data connection, because the user is on a phone call. Generally, WiFi and Bluetooth are utilized more actively on phones, when the phone is not being held against the head.)
So, on the one hand, theoretically (according to lab data and FCC filings for Google and Apple), using Glass leads to similar exposures as using an iPhone. On the other hand, these are exposures in a different set of frequencies, that are higher energy than those from an iPhone. What difference that makes is not known, but I will say that the currently known science demonstrates different sets of bioeffects resulting from exposures to different technologies that radiate different frequencies of EMF (e.g., power lines, FM radio, radar, television, microwave ovens, cell phones, etc).
What is the Relative Risk of Using Technology like Google Glass compared to an iPhone?
So, let’s assume that Google’s SAR value is accurate as an indicator of risk relative to other phones, and, for the purposes of this discussion, WiFi and Bluetooth radiation present no different risks than those from cell phone radiation.
There are still some fundamental and inescapable differences between Glass and an iPhone.
In terms of consumer experience, Google Glass is a fundamentally different piece of technology than an iPhone. As a result, exposures will be much higher than from an iPhone.
First, you can use tethered headsets with cell phones, to keep the cell phone (and thus the source of the radiation) much further away from the head. With Glass, no such mitigating step is possible, because the device is strapped to your head. There is no way to use Glass without strapping it to your head.
Second, not only is Glass attached to your head, the computer itself is very close to your temple and eye. These are two of the spots on the head most vulnerable to damage from EMF, because there is no bone to shield from the exposure. The eye, itself, is unshielded by anything. I never see anyone holding their iPhone up to their temple or eyeball. Glass enables a more direct exposure to the more vulnerable parts of the head.
And third, not only is the EMF exposure from Glass in a more vulnerable location, but Glass is there a lot. The form factor and supported use-cases of Glass encourage you to keep the darn thing on for hours at a time. Since there is no airplane mode (or other means to disable wireless communication) that means users are receiving continuously variable doses of microwave radiation, to their brains and eyes, for hours at a time. (In my tests, even when Glass is “idle” from the user’s perspective, there are frequent periods of significant EMF emissions, as the device syncs data wirelessly.) This means that the average duration of individual doses from Glass will be longer than for cell phones, and the cumulative exposures will accumulate more rapidly (i.e., you will reach 2,000 hours on Glass more rapidly than 2,000 hours on a cell phone).
Finally, it is important to note that EMF exposures from Glass are generally additive to those from cell phones. Virtually everyone who uses Glass has and uses a cell phone. In fact, much of Glass’ functionality only works when paired with a nearby cell phone. And so, Glass exposures are in addition to what wearers are already receiving from their phones. (As the Hardell data indicates, EMF exposures are cumulative.)
Having These Technologies, in Such Close Proximity To Brains & Eyes, Is Untested for Medium- and Long-Term Health Effects and Represents Use-Cases Not Considered by Existing FCC Regulations on Wireless Devices
For these reasons, I believe that Glass represents a tangible risk to the health of those who wear it — a risk quite likely greater than (and in addition to) that represented by those individuals’ existing cell phone usage.
But, to be clear, the actual risks of technology like Glass can not today be accurately known. To my knowledge, there have been no long-term studies on the different bioeffects that may result from holding a WiFi transmitter against your brain and eyeball, for hours at a time, on an almost daily basis.
And that’s precisely the point: Glass represents a completely different set of exposures than what’s been studied thus far. As you see from the Hardell study, you need many years of data for the results to be meaningful. So it’ll be awhile before anyone can tell you what the risks are that can result from using Glass, and other similar wearable technologies. All you can do is make best guesses based on the available data.
Google is selling a product that is untested as to the long-term human health effects.
Caveat emptor.
http://www.rblank.com/2013/07/22/understanding-the-health-risk-of-emf-emissions-from-google-glass/
