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Cell Phone Radiation Series - Part 4: What phones emit, bodies absorb
Research is not yet settled on exactly how dangerous cell phone radiation is to your health. But we at Environmental Working Group have seen enough studies with enough troubling results that we think it's worth your while to reduce your exposure to cell phone radiation.
When we talked a few weeks ago about insufficient government cell phone regulations, we discussed "SAR" values and the legal limits the government has set for the amount of radiation a phone can emit. But SAR values aren't always easy to pin down - so today we're going to look closely at what they are and how they can vary by phone.
What does SAR mean, anyway?
"SAR" stands for "specific absorption rate" - it's a measure of how much radiation is absorbed by your body, given in Watts per kilogram (W/kg). Scientists test for SAR values using models of the human body filled with viscous fluid designed to mimic human tissue. The phone is placed next to the mold, and while the phone transmits a signal, a probe inside the human model measures the absorbed energy levels. The phone's SAR value is designated as the highest amount of radiation detected during these tests.
What determines a phone's emission level?
A phone's SAR value is largely determined by the design of its inner hardware and antenna. But, since the SAR measures how much radiation is absorbed by your body (heartening, huh?), the value is determined by both a) the amount of radiation emitted by the phone, and b) what body part is doing the absorbing (yes, some absorb radiation more than others).
SAR values for an individual phone can vary, based on several factors:
- Network & frequency
Most phones sold today can operate on several networks (e.g. 2G v. 3G) and at different frequencies (which band of the network the phone is using to send and receive signals). The same phone can emit different levels of radiation depending on which network and which frequency it's being used on at any given time. - Where you're using it
Phones emit radiation when they're transmitting signals from your handset to a base station (cell tower), so the harder a phone has to work to send a signal, the more radiation it will emit. As a result, when you're using your phone far from a base station (say, in a rural area) or if there are physical obstacles in the way, the SAR value would be higher. - How you're using it
A phone also uses more power to transmit a voice signal, so texting emits less radiation than talking. - Where you're holding it
Originally, SAR measurements focused primarily on values when held at the head. But over time, cell phone use has changed - now we're carrying phones in our pockets and often leaving them there while talking on a headset or not using them.This means less radiation to the brain (that's good) but more to the lower torso. SAR values vary based on the type of body tissue absorbing the radiation, and research has shown that skin and muscles absorb more radiation than fat and bones. This raises concern about exposures at the waist, particularly to reproductive organs that don't have a protective layer of bone (like a skull provides the brain) shielding them from cell phone radiation
Also, as you'd instinctively assume, the farther away the phone is from you, the less radiation you'll absorb from it. Holding the phone 10 inches away can reduce radiation exposure by a factor of 400. (Another reason texting and a headset are good ideas - you'd be yelling to get heard while holding the phone that far away.)
SAR testing not perfect
Scientists acknowledge that SAR testing has significant precision problems, and current research is lacking in many ways. For instance, we don't know much about SAR values when phones are in "data mode" (you know you love those iphone apps), when they're held at various orientations (say, flipped around in your pocket) or how SAR values change for people of different ages and body types.
Children may be especially at risk, because their tissue conducts more (it has more ions than that of adults). Also, their thinner skulls don't provide as much of a radiation shield - one recent study showed that a child's head could absorb twice the amount of radiation as an adult's. As a result, kids using high-emitting, perfectly legal cell phones could be exposed to radiation over the legal limit.
You can make it better
More research is needed, but the U.S. currently lags behind Europe when it comes to knowing what's going on with cell phones (surprise!). Tell the Federal Communications Commission (FCC) and Food and Drug Administration (FDA) to update their cell phone regulations (which they haven't done since their introduction in the mid-1990's) by sending them an email using EWG's easy form.
And in the meantime, since SAR values vary so much, you can make choices to reduce your exposure. Use EWG's 8 tips to reduce your cell phone radiation exposure - they'll make good sense now that you understand the "why" behind them all.
Stay tuned for more on cell phone radiation in coming weeks -- including finding a phone that has low SAR values to start with.
Thanks to Flickr and Cyrillicus for the photo!
What's really sad is this is an old issue and I did a piece on it in 2006 http://www.opednews.com/articles/opedne_suzanne__060911_cell_phones__26_childr.htm and we are still trying to draw attention...but everyone is too darn busy texting, talking...playing the WII. Thank you for bringing to this the forefront!
Suzanne, Thanks for sharing your prior information on this. I think all of this just takes time, so your report in 2006, ours in 2009 and likely a bundle in between, will eventually create enough of a groundswell to create change. Soon after we released our report we testified in a US Senate hearing about radiation exposure - another form of progress. You can read about it here: http://bit.ly/4E6Ek2. All together, we'll move it forward. One report at a time! Best, Lisa
to much noise with this radiation stuff... be serious... who died from cell phones radiation ?
Alex, we can't definitively point to anyone "having died" specifically from cell phone radiation, but there is research that gives us cause for concern and makes us suggest limiting exposure. Check out this earlier post for more on the potential health effects of cell phone radiation: http://www.enviroblog.org/2009/10/fall-09-cell-phone-radiation-series-1-the-science.html
all the tips are very true. additional to Tip number two, aside from that, i also learned that, lesser signal means more or faster the battery will die, and this means that you'll have to consume more energy than usual. So wait for your phone's signal to rise as much as possible before using it.
I think the sharp spike in cancer incidence in the past 50 years is a very clear indicator that man-made factors are influencing us all-- from cell phones to pesticides to BPA and phthalates. ignoring these indicators and saying that data is simply "inconclusive" is only holding ourselves back from imposing stricter regulations on new technologies and chemicals, thusly making for a less-healthy world in the long run.
I have some questions for EWC on this issue, but none of their contact features on their site work…get database errors!
Nonetheless, I am glad they're bringing this topic to the fore. Now if they could get some much needed help with their web site.
There is something many people I know including myself are wondering about and I haven't read the answer anywhere yet.
Do wireless headsets emit any radiation???? If yes, wouldn't they be dangerous since some people are wearing them 24/7 ?