An anonymous reader writes "Sunday night in the UK, the BBC broadcast an alarmist Panorama news programme that suggested wireless networking might be damaging our health. Their evidence? Well, they admitted there wasn't any, but they made liberal use of the word 'radiation', along with scary graphics of pulsating wifi base stations. They rounded-up a handful of worried scientists, but ignored the majority of those who believe wifi is perfectly harmless. Some quotes from the BBC News website companion piece: 'The radiation Wi-Fi emits is similar to that from mobile phone masts ... children's skulls are thinner and still forming and tests have shown they absorb more radiation than adults'. What's the science here? Can skulls really 'absorb' EM radiation? The wifi signal is in the same part of the EM spectrum as cellphones but it's not 'similar' to mobile phone masts, is it? Isn't a phone mast several hundred/thousand times stronger? Wasn't safety considered when they drew up the 802.11 specs?"
Think of the children!!!
Seriously, it's sad that supposed "news" programs air things like this just to get ratings. What's even sadder is that lots of people believe them, so tech-savvy people like us now have to spend time explaining to Aunt Jane that the big evil wifi will not give her cat cancer.
The problem with programs like this is that it's likely create the same effect the reporting on MMR Vaccinations did. In that case despite massed ranks of scientific and medical studies and scientists saying there was no danger from MMR vaccinations a large number of people chose to believe that either there was a danger or there could be well be a danger based on reports in the media.
The trouble is that it's impossible to prove absolutely that wireless emissions are 100% safe and any good scientist if pressed will agree with that. A lot of people then choose to think that this must indicate there is a real danger and believe the shrieked warnings of people who think they have some disease absolutely caused by their wireless router. Pointing out that there is no evidence of wireless emissions being harmful is a wasted excercise on these people who only seem to be able to think in black and white
"No evidence yet !" they wail "But you wont tell me it's 100% safe either ! Destroy all wireless !"
What's often missing is a sense of perspective, cars are extremely dangerous and kill hundreds of thousands people a year throughout the world but most people are perfectly happy to drive them or walk in the vicinity of them.
I think the difference might be that people can easily see the dangers posed by cars themselves whereas there is no visible evidence of MMR vaccines or phone masts killing people so people have no way of easily assesing the threat and instead have to rely on people telling them things they don't really understand.
Obviously we can't do anything about people choosing not to buy wireless routers for use in their own homes because of a fear of the perceived risks they pose but we should be able to stop these people stopping the use of these things in society in general, e.g. in schools where we should use proper standards of evidence for assessing threat levels and not allow even a majority of parents to make changes unless they can present proper evidence for their beliefs.
All day we're around Microwaves, XRays, High voltage lines, lights, televisions and Radio signals. There are TONS, of course... but how much more is actually from outside the atmosphere?
The only thing that's frying our kid's brains are their ideas. I'm not overlooking child safety, but there are WAY more harmful waves out there than WiFi.
In the meantime, their children are outside getting burnt without sunscreen.
All day we're around Microwaves, XRays, High voltage lines, lights, televisions and Radio signals. There are TONS, of course... but how much more is actually from outside the atmosphere?
Actually, in the late 1890's and early 1900's people who worked in the field of XRays often died from over exposure of radiation. They simply didn't know what they heck they were working with. Thomas Edison was so horrified of what happened to his worker Clarence Dally [wikipedia.org] due to radiation poisoning that he abandoned any further research with X-rays. Not to mention Marie Curie death due to exposure to radiation and countless others that worked in her field.
Back then of course people thought drinking radium was a good health product and that shoe sales man could operate their x-ray on a casual basis to fit shoes giving them more REM exposure in a day than a modern nuclear power plant worker is allowed a year.
I'm not saying that WiFi is dangerous, but as a precedent people have often generally underestimated some dangers with emerging technologies and we should never discount such a thing could happen. Of course we due scientific study than complete news worthy paranoia.
I see lots of complaints of this. People who are extra sensitive to electronics and such. I would like to submit these people to a double blind study so that we can prove (or disprove) the effects are real, and not people who just have something else wrong with them that makes them feel more tired, or have headaches, or unable to concentrate, or whatever other symptoms they have. It seems to me like there's a lot of anecdotal evidence, but that there isn't any real studies being done.
Well again, on the show they said the woman in question was able to tell when wifi was on or off 2/3rds of the time in tests, 66% isn't really a high enough chance for me to believe hers is a real known problem, particularly when they didn't explain her testing methodology, if they only ran 3 tests for example then get 2 out of 3 right is in the correct range of a 50% chance of getting it right by mere guessing should she have got a 4th test wrong.
They did however mention that Sweden recognises electro-sensitivity as an official disability so there is perhaps some credibility in the whole idea, how much is still questionable of course.
Typical wifi - 100mW. 2g Cell tower - 20-100W. In cities they are using micro cells, which typically have about 3W power. There are experiments which show cell phones are a little dangerous, and there are scientist, who tried for years to show there is big danger, but found none and converted to "no harm" camp. So YMMV.
Output power doesn't tell the whole story, proximity is much more important. Electromagnetic power density dissipates at the inverse square of the distance from the emitter.
All you have to do is consider the receive power. It is typical to receive a wifi signal at -65dBm, while a cell signal indoors is seldom stronger then -80dBm. Even if you consider multiple channels and multiple carriers on each cell tower, you would seldom get a composite power level greater then -70dBm indoors. -65dBm is approximately 3 times stronger then -70dBm. Of course these are typical levels, but when you consider how many wifi networks you usually pick up in your own home (esp. apartment), you will almost always receive a far greater exposure to electromagnetic radiation from wifi then from cell phone towers.
Full disclosure: I perform power density theoretical studies and measurement levels for the wireless industry, and also design in-building wireless repeater systems so I have a fair bit of experience here.
Presumably this scientist was on phase 3; attempting to test his hypothesis. When they testing indicated that the hypothesis was false, he altered it to conform to the newer observations.
Unfortunately life is not Star Trek. The pragmatic method is:
1. Hypothesise.
2. Beg.
3. "Prove".
4. Publish.
Science costs money. Money comes from benefactors. Benefactors don't like surprises. You publish the results you were paid to discover, or you don't get more money. Welcome to the real world. Wear a helmet.
802.11b/g uses 2.4GHz radio waves. That's the same frequency range as microwave ovens. Microwave ovens work because the microwaves are absorbed by the bonds in the water molecules of food (which is why dry food does not cook in microwave ovens).
So yes, human tissue that contains water can absorb WiFi radiation. That is a fact.
What is not known is: how much absorption of that radiation is bad for the kids?
I've always wondered why these networks use 2.4GHz radio waves.
I'm not a physicist, so really: is there an advantage to this frequency? Why not 1.2GHz.. or 3.6GHz, etc.? Why something so close to the frequency range of microwave ovens?
If this is a really dumb question, I already ask for forgiveness.:)
802.11a uses the 5GHz range, out of the way of microwave ovens.
2.4GHz was used because it was available for use, i.e., it would not interfere with frequencies already allocated to other services in the microwave area.
In other words, the thought process (if you can call it that) was not, "let's find a frequency for 802.11b that is free of interference from other sources". It was more along the lines of, "let's find a frequency for 802.11b so that 802.11b won't mess up anything of import, i.e., microwave ovens don't really care about interference from your wireless router.
By the way, the same "thought" process was used to pick a frequency for the 2.4GHx wireless phones.
I've always wondered why these networks use 2.4GHz radio waves.
I think it mainly had to do with the fact that the same part of 2.4GHz is open for unlicensed use globally. The other unlicensed ISM (industrial-scientific-medical) bands in the United States are used for other stuff in other nations. The easiest example is 900mhz. Part of it is available for unlicensed use in the United States. But as anybody with a quad-band GSM phone knows, that's a cellular band in most of the rest of the world.
I believe there is a scientific reason for the ISM band being there - I think water has a bit of an absorption peak in the 2.4 GHz region.
For this reason, 2.4 GHz wasn't too hot for long-haul communications due to water vapor in the air, so no one was in a rush to license spectrum for it, and no one fought designating it as an "Industrial, Scientific, Medical" band. (with the primary use in all three of those categories being to take advantage of that water absorption peak for heating.) Now, because the band is such a cesspool, no one minded allowing low-power unlicensed communications in that band.
Now, as to the health effects of this - Yes, the water in your body is more likely to absorb 2.4 GHz RF. No, that absorption will not do any cumulative damage. Absorbing 2.4 GHz RF will make the water molecules in your body vibrate a little more (i.e. it will heat you up.) At high powers, this does become dangerous as the heat basically cooks you from the inside (just like a microwave oven). At low powers (with 802.11 being a great example), the body is able to safely dissipate the heat rapidly enough so that not only is no damage done, the change in temperature at any point in the body is negligible. You're more likely to get burned by touching the heatsink of the RF amp than you are by touching a circuit trace carrying RF at those power levels.
RF radiation is nothing like nuclear radiation - the critical difference is that nuclear radiation is ionizing, that is to say that it can not only vibrate molecules a bit, but it has enough energy to alter them. This has the effect of "flipping bits" in your DNA and other such nasty stuff. Since "bit flipping" can have cumulative effects, low levels of ionizing radiation can be dangerous in the long term, because the damage accumulates. With RF, it doesn't unless power levels are so high as to induce temperatures that cause thermal damage.
Prior to graduate school, I worked at a company that built RF power amplifiers for cell towers (30-45W average power output), and many of my coworkers had been working with microwave RF amps since the very first cell system Motorola deployed. (Yes, we had some ex-Motorola old hands there, who had interesting stories from the early days when the system designers were also heavily involved with the installation process of new base stations.) No health problems whatsoever.
Since graduate school, one of the tasks of my department is taking equipment through EMI testing. We're frequently right at OSHA RF exposure limits - no health problems with any of us (Well, at least no new ones that weren't preexisting conditions), even our mentor who has been doing this for 20-30 years.
Except, you know...the nuclear radiation that is RF radiation...which is all of it.
While gamma radiation is indeed electromagnetic, what pretty much everyone calls RF is actually whatever is below the infrared (i.e. microwave downward). Also, not all nuclear radiation is electromagnetic. Ever heard of alpha and beta particles -- those are ionising too.
What about UV? That causes mutations too. Does that have as much energy as gamma (the answer: not if the amplitude is the same)? This is just crap. Any kind of radiation can have three effects on cells:
What the hell is "amplitude" supposed to mean. This isn't about the amount of power, but the nature of the radiation (quantum physics 101). Either a certain radiation is ionising or it's not (well of course, there's a range where it depends on the exact molecule). For both UV and gamma, the energy of a photon is enough to eject an electron (or move it where it's not supposed to be) and thus cause damage to the DNA. For microwaves, you can pour as much energy as you like, it's just not going to happen. The only potential harm from microwave is the fact that it can potentially heat up the body (but it takes more than a few mW).
The more energy, the more likely to get #3. However, there are agents in the skin to absorb most of the energy in most of the RF spectrum. Any part of the spectrum can cause mutations if you can get it to do step #2 and not step #3.
No, mutations can only be caused by ionising radiation. A microwave oven will cook you, but it will *not* cause mutations because the microwave photons simply don't have enough energy to displace electrons. Also, why do you think we put sunscreen to protect our skin from UV radiation while leaving it fully exposed to infrared and visible light, which make up most of the total radiated power from the sun (and far more than UVs)?
Your story aside, that much power could easily burn someone to cinders if they happened to be sitting on the focal point of a microwave dish.
No, it will have about the same effect as using a 20 cm magnifier in the sun. Would probably hurt, but not kill you.
It's must be embarrassing when you write a post to discredit someone, and it ends up revealing that you didn't understand what was being said.
Lets go back to quantum physics / physical chemistry / modern physics (depending on the curriculum you studied in college). Electromagnetic energy has a dual wave-particle nature. The particle nature revealed by the fact that EM has a specific quanta (photon for EM in the light frequency range) of energy that is directly related to its frequency. The higher the frequency the greater the energy contained in the quanta or in the photon. This means that high frequency EM sources like X-rays, gamma rays, and beta rays (in order of increasing frequency) contain much more powerful quanta then low frequency EM sources (radio waves).
So why is the energy level in the quanta important? Well, if you recall your chemistry, electrons can be moved to higher orbits, or even dislodged from an atom by adding an exact amounts of energy to them (only the exact amount will cause a change, energy amounts greater or lower then the exact amount needed will have no effect on the electrons of an atom). The very lowest level of energy required to disturb an electron from the outermost shell of any atom just happens to correspond to the energy level of a quanta of an EM wave at the frequency of ultraviolet light. This means that all EM energy below this minimum frequency threshold are unable to disturb electrons in an atom, but above this frequency they can begin to alter the atom structure of matter, and the higher the frequency the greater they can alter the structure. Radiation capable of changing atomic structures is known as ionizing radiation, radiation incapable of causing changes is known as non-ionizing radiation.
So this explains why ultraviolet light is carcinogenic, it is just over the threshold of ionizing radiation, while red, orange, yellow, green, and blue light (Roy G. Biv) are perfectly safe (well, not carcinogenic anyway).
So, back to the whole point, RF radiation is nothing like nuclear radiation, unless you are ignorant and easily swayed by scaremongering tactics that use the word 'radiation' as a synonym for 'evil'.
1. Your body absorbs EM radiation from the infra-red band! Also known as heat, IR sources are everywhere and can eliminate the need for you to wear thick clothing.
2. Your skin absorbs EM radiation from the optical spectrum! Black people are particularly vulnerable to this type of radiation absorption.
3. Your skin absorbs radiation from the UV spectrum! Millions of people develop tans and synthesize vitamin D every year due to UV radiation absorption.
Notice that in all these cases, we're talking about the conversion of energy to *heat* by the absorbing tissue. Raising an alarm about this is like getting up in arms about the dangers of "dihydrogen monoxide". In fact, radio-band emissions are even lower-energy than the energy spectra listed above, and is thus generally even more benign.
Dangerous radiation is high-energy ionizing radiation, like that found in the X-ray and gamma spectra. Such radiation has the capacity to damage cell DNA and cause radiation sickness, but that's a completely different animal than what this article is dealing with.
the FCC has specifications of radiation density versus frequency that are limits in their rulebooks, limits used to isolate access to radio facilities from microwaves to commercial broadcasters... to ham radio operators burning electrons in the basement. these have been codified by medical research. if you're going for an advanced ham license, you have to study the milliwatts per meter limits, the question occasionally comes up on the test.
so there are 3/4 million americans who know this, not just ten academics in the tower.
where the hell did this whining of Luddites come from, and why wasn't it left there?
Basicaly in the old country they have a government official who is unprepared to admit radio waves, mobile phones etc, are safe; no matter what the evidence.
Mobile phone towers are many, many times more total output. Yes, both transmit in the microwave spectrum, but the 'notch' in the microwave spectrum that resonates water (and thereby heats your food, cooks your brain) is extremely tight (2.45 Ghz). If you're above it or below it, the water molecules in your body (or food) simply won't vibrate/resonate and there's no heating. And yeah, people use 'radiation' all the time to invoke the panic of ionizing nuclear radiation (bad) with electromagnetic radiation (mostly harmless). (Meanwhile these same people go suntan in the name of health, basking in the glow of an unshielded fusion reactor. Yay humanity.)...People who live by the sword get shot by those who dont.
The operating frequency of microwave ovens was chosen to be in an unlicensed (ISM) frequency band, that would provide good penetration into foods, and lent itself to the mass production of inexpensive magnetron tubes.
The lowest resonant frequency for a water molecule is 22.235 GHz, or nearly 10X the operating frequency of a microwave oven.
Actually, 2.45 GHz isn't the maximum of the absorbance for microwaves. If it was, all the energy would be dumped at the surface of food, and there would be virtually no penetration. Water absorbs over a broad spectral range, at least in the liquid phase, where quantised rotational bands can be ignored.
And what you say about the different energies of radiation is mostly true, although EM radiation covers a range that includes UV, x-rays and gamma radiation, which are not very good for you.
The BBC website has a Wi-fi health fears are 'unproven' [bbc.co.uk] story which addresses this. My favourite quote, from Professor Will J Stewart:
"This is not to say that all electromagnetic radiation is necessarily harmless - sunlight, for example, poses a significant cancer risk; so if you are using your laptop on the beach make sure and get some shade."
Frankly the BBC was irresponsible in showing this episode of Panorama. I'm against censorship, but informational programs produced by a tax-payer funded media outlet should not be spouting such paranoid, biased crap as Panorama did last night.
This is arguably the worst case of the BBC scrambling for ratings I've ever witnessed. Never before have I seen them stoop so low to try and raise viewing figures. I was sat watching it waiting for the part where they offer the opposing view of the situation to allow people to make their own minds up, unfortunately however, that never came - it was one sided anti-wifi propaganda all the way through, from start to finish.
About the only attempt at offering an opposing view was the brief mention that the WHO states that there is no known risk of wifi at this time, this brief mentioning was followed by a couple of minutes of slagging off the credibility of the WHO.
I'm no expert when it comes to wifi, radiation and so forth and I'm not claiming that wifi is 100% safe - it may well pose risks. The problem with the program however seemed to be that it's entire argument is based on the premise that there is some other danger to human health from radiation other than the heating effect, and from what I've read elsewhere, there is absolutely no evidence that there is any effect other than the heating effect. I'm sure those with better scientific knowledge may be able to correct me on this if I'm wrong, but if it's true as has been reported by other news outlets (and in fact even by the BBC themselves online) then the majority of the program was fundamentally flawed in it's arguments.
What bothers me most is that we've gone from one lazy teacher looking for an excuse to get time off work claiming that wifi gives him headaches to a national wifi scandal. The worst part is that most reports that refer to the teacher in question who sparked this row ignore the fact that in scientific tests the teacher could neither a) tell whether wifi was on or off and b) now claims he gets these headaches wherever he is, even when not around wifi!
If Wifi does indeed pose a threat then I agree we need to do something, but thus far this seems equivalent to the whole terrorism/think of the children/drugs/computer games make people kill FUD.
My son was diagnosed with leukaemia (AML15 for those interested) on his 1st birthday. My first trip home from the hospital I turned of the wireless router, cordless phones and my mobile/cell. He's now 3, built like an ox and hopefully fixed for good.
My neighbours all have wireless, cordless and mobiles so I eventually turned all mine back on. Two years on and no-one else in the house, including my 2 other boys, have cancer.
Who knows what caused it. Live life to the full, make the kids smile and if low power wireless gadgets worry you, please get out more.
After re-reading Richard Feynman's lecture on Cargo Cult Science. With its demolition of "experiments" without controls, and how people kept on doing pointless lab rat experiments after the methodology was debunked, it's a sad saga - which is just as true today after so much "progress".
Unfortunately, in the UK at least, the number of scientifically trained journalists can probably be counted on one of Ben Goldacre's fingers.
Interesting that none of the phone mast posts seem to have remembered the inverse square law - sorry if you did and I missed you - which mean that radiation levels at the ground are a tiny fraction of what you get from the phone. And that nobody has mentioned all the radiation we used to get from TV and radio sets. As I recall, the radiation you get from an old tube superhet set (from the IF) is much more intense than the radiation from WiFi. It is lower frequency, but then the skin effect is less, and as anybody who ever played about with NMR will recall, VHF does things to organic molecules.
We'd better take action now. Let's get rid of all that nasty radioactivity - oops, Madam, there goes your granite kitchen work surfaces and your low-sodium salt. And all the radiation sources beginning with the most intense. So we've now turned off the Sun, mobile phones, radio, TV, electrical generating. We can't use coal (have you looked at what you get in the ash). So we can just sit in the dark and freeze.
As for the leukaemia cases - I have long believed that a far more convincing explanation is exposure to farm chemicals, pesticides, and the new virus and bacterial strains resulting from population movement. It is possible that farming overspray with chemicals which have been subsequently banned is a more probable cause of leukaemia clusters than, say, living near a rural electrical supply line. In the UK, and probably in the US too, the parts of Government which deal with farming tend to be extremely secretive and their decisions are often hard to understand. To my mind, they are far more likely to suppress information about such things than the relatively open parts of Government which deal with non-farming health and safety.
hell, global warming. isn't that that piece of crap those european scientists promote just to anger and disgruntle the whole hummer-driving-air-conditioning-the-whole-place-am erican-folks? yeah, that's FUD at it's best. actually it's all about selling more european, pseudo-eco-friendly products in the states, to ruin the american markets and thus stopping the war against terrorism by an act of countercultural inner corrosion.
They got it all wrong. The problem isn't with WiFi, the problem is when the signal carries the kill bit [securescout.com], passing through your body and causing extreme cellular damage. That's why most of the time the studies show up nothing.
Damn that global conspiracy of nearly 100% of the world's climate scientists! Even the politicians are finally getting in on it, after decades of dedicated FUD spreading by those evil scientists. They must be laughing, laughing I say, all the way to the... err...
FYI, I know perfectly well how science operates. I was not making any personal judgement on whether global warming is real, caused by human activity, or by the flying spaghetti monster.
I was attacking the position (hopefully with a little humour) that global warming is all FUD. That position seems untenable; that a large majority of the world's scientists would all conspire to promote falsehood. They may be entirely wrong, but the majority are in broad agreement.
Given that the consequences of not acting on this information may be disastrous, the precautionary principle suggests that we listen to them. Taken to its logical extreme, you would be advocating never acting on any scientific advice, as it *might* be wrong.
admitting in the brief write-up that there isn't any science behind this?
Maybe they read the article, which points out various scientists who argue that there IS evidence about it.
I've got to say, the ridiculously emotional backlash I see on/. against ANY suggestion that wifi or cell phone signals MAY cause some adverse health effects is sloppy, anti-science thinking.
I personally don't believe cell phone signals or wifi signals are strong enough to cause health problems. But I'm certainly not going to be arrogant enough to proclaim that there absolutely are no health problems and we shouldn't even look at the problem.
I thought/. != FUD.
Please, half of/. is FUD./. is only anti-FUD in regards to its pet causes.
Well I don't think programs that only exist to scare you are worthwhile. I've never seen a Panorama program that wasn't a scare-fest. When you watch one on a topic you know nothing about the scientists seem well informed and the threats seem genuine. It's only when you watch a Panorama program on a topic you're remotely familiar with that you realize what nonsense it is.
One of them was about the dangers of black holes. They'll boil the oceans, suck the life right off the planet, there's a super massive one at the center of our galaxy, they feed and then they stay silent, drifting through space until WHAM. Lots of sound bytes of scientists saying "it's only a matter of time", "you can't see them, but we know they're there", "we have no idea how many there are", etc. In only 5 billion years our galaxy will collide with another one, and we might drift right into that galaxy's super massive black hole, etc, etc.
It's that sort of programming, and if they convince laypeople that more money needs to be spent on researching this than is really necessary it only does damage.
It's that sort of programming, and if they convince laypeople that more money needs to be spent on researching this than is really necessary it only does damage.
No amount of funding is too much for the issue of finding black holes. I still have 17 socks and a car key unaccounted for.
Planck's constant is so small that interactions between electromagnetic waves and molecules cannot be chemically specific.
What do you mean by that? If that were true, then spectroscopy [wikipedia.org] wouldn't be possible. Different molecules do indeed interact with the EM-spectrum quite differently. They absorb at different wavelengths, and exhibit other effects (like Raman scattering [wikipedia.org]) that are indeed chemically-specific. In fact, spectroscopy is the most common way of identifying chemical species.
Different parts of the EM-spectrum probe different aspects of molecules. (Visible light probes electronic structure, infrared light interacts with molecular vibrations, etc.) Even the radiofrequency range of the spectrum interacts with molecules in a chemically-specific way: microwave-region EM-radiation probes the rotational modes of molecules, and radiofrequency spectroscopy can also probe nuclear states (see NMR [wikipedia.org]).
If I've misunderstood what you meant, please set me straight.
(By the way, I do agree that the energy from a WiFi signal will be absorbed by most common materials and lead to a barely noticeable increase in temperature. But that doesn't mean that the process is not chemical-specific. For instance, some materials will absorb more of the WiFi signal than others.)
Won't somebody please... (Score:5, Insightful)
Seriously, it's sad that supposed "news" programs air things like this just to get ratings. What's even sadder is that lots of people believe them, so tech-savvy people like us now have to spend time explaining to Aunt Jane that the big evil wifi will not give her cat cancer.
Re:Won't somebody please... (Score:4, Funny)
Is that when there's a cat growing out of her chest cancer?
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Re:Won't somebody please... (Score:5, Insightful)
The trouble is that it's impossible to prove absolutely that wireless emissions are 100% safe and any good scientist if pressed will agree with that. A lot of people then choose to think that this must indicate there is a real danger and believe the shrieked warnings of people who think they have some disease absolutely caused by their wireless router. Pointing out that there is no evidence of wireless emissions being harmful is a wasted excercise on these people who only seem to be able to think in black and white
"No evidence yet !" they wail "But you wont tell me it's 100% safe either ! Destroy all wireless !"
What's often missing is a sense of perspective, cars are extremely dangerous and kill hundreds of thousands people a year throughout the world but most people are perfectly happy to drive them or walk in the vicinity of them.
I think the difference might be that people can easily see the dangers posed by cars themselves whereas there is no visible evidence of MMR vaccines or phone masts killing people so people have no way of easily assesing the threat and instead have to rely on people telling them things they don't really understand.
Obviously we can't do anything about people choosing not to buy wireless routers for use in their own homes because of a fear of the perceived risks they pose but we should be able to stop these people stopping the use of these things in society in general, e.g. in schools where we should use proper standards of evidence for assessing threat levels and not allow even a majority of parents to make changes unless they can present proper evidence for their beliefs.
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Re:Won't somebody please... (Score:4, Funny)
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What crap. (Score:5, Insightful)
The only thing that's frying our kid's brains are their ideas. I'm not overlooking child safety, but there are WAY more harmful waves out there than WiFi.
In the meantime, their children are outside getting burnt without sunscreen.
Re:What crap. (Score:5, Funny)
*shivers*
OMG SOMEBODY THINK OF THE CHIIILDREN
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Re:What crap. (Score:5, Funny)
Please stop, it's too horrible! The worst of it all is that my PC is as we speak radiating heat.
That's the same kind of radiation that is used in conventional ovens!
It can cook stuff to death!
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Re:What crap. (Score:5, Interesting)
Actually, in the late 1890's and early 1900's people who worked in the field of XRays often died from over exposure of radiation. They simply didn't know what they heck they were working with. Thomas Edison was so horrified of what happened to his worker Clarence Dally [wikipedia.org] due to radiation poisoning that he abandoned any further research with X-rays. Not to mention Marie Curie death due to exposure to radiation and countless others that worked in her field.
Back then of course people thought drinking radium was a good health product and that shoe sales man could operate their x-ray on a casual basis to fit shoes giving them more REM exposure in a day than a modern nuclear power plant worker is allowed a year.
I'm not saying that WiFi is dangerous, but as a precedent people have often generally underestimated some dangers with emerging technologies and we should never discount such a thing could happen. Of course we due scientific study than complete news worthy paranoia.
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Eek! (Score:5, Funny)
Re:Eek! (Score:4, Interesting)
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Re:Eek! (Score:4, Funny)
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Re:Eek! (Score:5, Insightful)
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Re:Eek! (Score:5, Interesting)
They did however mention that Sweden recognises electro-sensitivity as an official disability so there is perhaps some credibility in the whole idea, how much is still questionable of course.
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Re:Eek! (Score:4, Informative)
The "electrosensitive" crackpots couldn't detect a mobile phone signal even after 50 minutes of continuous exposure.
http://www.bmj.com/cgi/eletters/bmj.38765.519850.
It could be psychosomatic, it could be some other mental or physical illness, but it isn't EM radiation that's making them ill.
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FUD (Score:4, Insightful)
Re:FUD (Score:5, Insightful)
All you have to do is consider the receive power. It is typical to receive a wifi signal at -65dBm, while a cell signal indoors is seldom stronger then -80dBm. Even if you consider multiple channels and multiple carriers on each cell tower, you would seldom get a composite power level greater then -70dBm indoors. -65dBm is approximately 3 times stronger then -70dBm. Of course these are typical levels, but when you consider how many wifi networks you usually pick up in your own home (esp. apartment), you will almost always receive a far greater exposure to electromagnetic radiation from wifi then from cell phone towers.
Full disclosure: I perform power density theoretical studies and measurement levels for the wireless industry, and also design in-building wireless repeater systems so I have a fair bit of experience here.
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Re:FUD (Score:5, Insightful)
1. Observe.
2. Hypothesise.
3. Test.
4. Repeat.
Presumably this scientist was on phase 3; attempting to test his hypothesis. When they testing indicated that the hypothesis was false, he altered it to conform to the newer observations.
Unfortunately life is not Star Trek. The pragmatic method is:
1. Hypothesise.
2. Beg.
3. "Prove".
4. Publish.
Science costs money. Money comes from benefactors. Benefactors don't like surprises. You publish the results you were paid to discover, or you don't get more money. Welcome to the real world. Wear a helmet.
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WiFi is microwaves (Score:5, Informative)
802.11b/g uses 2.4GHz radio waves. That's the same frequency range as microwave ovens. Microwave ovens work because the microwaves are absorbed by the bonds in the water molecules of food (which is why dry food does not cook in microwave ovens).
So yes, human tissue that contains water can absorb WiFi radiation. That is a fact.
What is not known is: how much absorption of that radiation is bad for the kids?
Re:WiFi is microwaves (Score:4, Interesting)
I'm not a physicist, so really: is there an advantage to this frequency? Why not 1.2GHz.. or 3.6GHz, etc.? Why something so close to the frequency range of microwave ovens?
If this is a really dumb question, I already ask for forgiveness.
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Re:WiFi is microwaves (Score:5, Informative)
2.4GHz was used because it was available for use, i.e., it would not interfere with frequencies already allocated to other services in the microwave area.
In other words, the thought process (if you can call it that) was not, "let's find a frequency for 802.11b that is free of interference from other sources". It was more along the lines of, "let's find a frequency for 802.11b so that 802.11b won't mess up anything of import, i.e., microwave ovens don't really care about interference from your wireless router.
By the way, the same "thought" process was used to pick a frequency for the 2.4GHx wireless phones.
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Re:WiFi is microwaves (Score:4, Informative)
I've always wondered why these networks use 2.4GHz radio waves.
I think it mainly had to do with the fact that the same part of 2.4GHz is open for unlicensed use globally. The other unlicensed ISM (industrial-scientific-medical) bands in the United States are used for other stuff in other nations. The easiest example is 900mhz. Part of it is available for unlicensed use in the United States. But as anybody with a quad-band GSM phone knows, that's a cellular band in most of the rest of the world.
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Re:WiFi is microwaves (Score:5, Informative)
For this reason, 2.4 GHz wasn't too hot for long-haul communications due to water vapor in the air, so no one was in a rush to license spectrum for it, and no one fought designating it as an "Industrial, Scientific, Medical" band. (with the primary use in all three of those categories being to take advantage of that water absorption peak for heating.) Now, because the band is such a cesspool, no one minded allowing low-power unlicensed communications in that band.
Now, as to the health effects of this - Yes, the water in your body is more likely to absorb 2.4 GHz RF. No, that absorption will not do any cumulative damage. Absorbing 2.4 GHz RF will make the water molecules in your body vibrate a little more (i.e. it will heat you up.) At high powers, this does become dangerous as the heat basically cooks you from the inside (just like a microwave oven). At low powers (with 802.11 being a great example), the body is able to safely dissipate the heat rapidly enough so that not only is no damage done, the change in temperature at any point in the body is negligible. You're more likely to get burned by touching the heatsink of the RF amp than you are by touching a circuit trace carrying RF at those power levels.
RF radiation is nothing like nuclear radiation - the critical difference is that nuclear radiation is ionizing, that is to say that it can not only vibrate molecules a bit, but it has enough energy to alter them. This has the effect of "flipping bits" in your DNA and other such nasty stuff. Since "bit flipping" can have cumulative effects, low levels of ionizing radiation can be dangerous in the long term, because the damage accumulates. With RF, it doesn't unless power levels are so high as to induce temperatures that cause thermal damage.
Prior to graduate school, I worked at a company that built RF power amplifiers for cell towers (30-45W average power output), and many of my coworkers had been working with microwave RF amps since the very first cell system Motorola deployed. (Yes, we had some ex-Motorola old hands there, who had interesting stories from the early days when the system designers were also heavily involved with the installation process of new base stations.) No health problems whatsoever.
Since graduate school, one of the tasks of my department is taking equipment through EMI testing. We're frequently right at OSHA RF exposure limits - no health problems with any of us (Well, at least no new ones that weren't preexisting conditions), even our mentor who has been doing this for 20-30 years.
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Re:WiFi is microwaves (Score:5, Informative)
While gamma radiation is indeed electromagnetic, what pretty much everyone calls RF is actually whatever is below the infrared (i.e. microwave downward). Also, not all nuclear radiation is electromagnetic. Ever heard of alpha and beta particles -- those are ionising too.
What about UV? That causes mutations too. Does that have as much energy as gamma (the answer: not if the amplitude is the same)? This is just crap. Any kind of radiation can have three effects on cells:
What the hell is "amplitude" supposed to mean. This isn't about the amount of power, but the nature of the radiation (quantum physics 101). Either a certain radiation is ionising or it's not (well of course, there's a range where it depends on the exact molecule). For both UV and gamma, the energy of a photon is enough to eject an electron (or move it where it's not supposed to be) and thus cause damage to the DNA. For microwaves, you can pour as much energy as you like, it's just not going to happen. The only potential harm from microwave is the fact that it can potentially heat up the body (but it takes more than a few mW).
The more energy, the more likely to get #3. However, there are agents in the skin to absorb most of the energy in most of the RF spectrum. Any part of the spectrum can cause mutations if you can get it to do step #2 and not step #3.
No, mutations can only be caused by ionising radiation. A microwave oven will cook you, but it will *not* cause mutations because the microwave photons simply don't have enough energy to displace electrons. Also, why do you think we put sunscreen to protect our skin from UV radiation while leaving it fully exposed to infrared and visible light, which make up most of the total radiated power from the sun (and far more than UVs)?
Your story aside, that much power could easily burn someone to cinders if they happened to be sitting on the focal point of a microwave dish.
No, it will have about the same effect as using a 20 cm magnifier in the sun. Would probably hurt, but not kill you.
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Re:WiFi is microwaves (Score:5, Informative)
Lets go back to quantum physics / physical chemistry / modern physics (depending on the curriculum you studied in college). Electromagnetic energy has a dual wave-particle nature. The particle nature revealed by the fact that EM has a specific quanta (photon for EM in the light frequency range) of energy that is directly related to its frequency. The higher the frequency the greater the energy contained in the quanta or in the photon. This means that high frequency EM sources like X-rays, gamma rays, and beta rays (in order of increasing frequency) contain much more powerful quanta then low frequency EM sources (radio waves).
So why is the energy level in the quanta important? Well, if you recall your chemistry, electrons can be moved to higher orbits, or even dislodged from an atom by adding an exact amounts of energy to them (only the exact amount will cause a change, energy amounts greater or lower then the exact amount needed will have no effect on the electrons of an atom). The very lowest level of energy required to disturb an electron from the outermost shell of any atom just happens to correspond to the energy level of a quanta of an EM wave at the frequency of ultraviolet light. This means that all EM energy below this minimum frequency threshold are unable to disturb electrons in an atom, but above this frequency they can begin to alter the atom structure of matter, and the higher the frequency the greater they can alter the structure. Radiation capable of changing atomic structures is known as ionizing radiation, radiation incapable of causing changes is known as non-ionizing radiation. So this explains why ultraviolet light is carcinogenic, it is just over the threshold of ionizing radiation, while red, orange, yellow, green, and blue light (Roy G. Biv) are perfectly safe (well, not carcinogenic anyway).
So, back to the whole point, RF radiation is nothing like nuclear radiation, unless you are ignorant and easily swayed by scaremongering tactics that use the word 'radiation' as a synonym for 'evil'.
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Re:WiFi is microwaves (Score:5, Informative)
http://en.wikipedia.org/wiki/Microwave_oven [wikipedia.org]
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Re:WiFi is microwaves (Score:5, Funny)
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Re:WiFi is microwaves (Score:4, Informative)
Typical microwave oven = 750W-1500W (750,000 - 1,500,000 mW)
Big difference.
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Re:WiFi is microwaves (Score:5, Informative)
1. Your body absorbs EM radiation from the infra-red band! Also known as heat, IR sources are everywhere and can eliminate the need for you to wear thick clothing.
2. Your skin absorbs EM radiation from the optical spectrum! Black people are particularly vulnerable to this type of radiation absorption.
3. Your skin absorbs radiation from the UV spectrum! Millions of people develop tans and synthesize vitamin D every year due to UV radiation absorption.
Notice that in all these cases, we're talking about the conversion of energy to *heat* by the absorbing tissue. Raising an alarm about this is like getting up in arms about the dangers of "dihydrogen monoxide". In fact, radio-band emissions are even lower-energy than the energy spectra listed above, and is thus generally even more benign.
Dangerous radiation is high-energy ionizing radiation, like that found in the X-ray and gamma spectra. Such radiation has the capacity to damage cell DNA and cause radiation sickness, but that's a completely different animal than what this article is dealing with.
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"Can skulls really 'absorb' EM radiation?" (Score:3, Funny)
"Do not look into laser with remaining eye" is also appropriate here...
Researchers. On. Drugs. (Score:5, Informative)
the FCC has specifications of radiation density versus frequency that are limits in their rulebooks, limits used to isolate access to radio facilities from microwaves to commercial broadcasters... to ham radio operators burning electrons in the basement. these have been codified by medical research. if you're going for an advanced ham license, you have to study the milliwatts per meter limits, the question occasionally comes up on the test.
so there are 3/4 million americans who know this, not just ten academics in the tower.
where the hell did this whining of Luddites come from, and why wasn't it left there?
Good analisys at El Reg (Score:3, Informative)
Basicaly in the old country they have a government official who is unprepared to admit radio waves, mobile phones etc, are safe; no matter what the evidence.
radiation buzz buzz (Score:3, Insightful)
2.45GHz is NOT the resonant frequency of water... (Score:4, Informative)
The lowest resonant frequency for a water molecule is 22.235 GHz, or nearly 10X the operating frequency of a microwave oven.
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2.45 GHz isn't maximum absorbance (Score:4, Informative)
And what you say about the different energies of radiation is mostly true, although EM radiation covers a range that includes UV, x-rays and gamma radiation, which are not very good for you.
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Website story (Score:4, Insightful)
The BBC should know better... (Score:5, Insightful)
This is arguably the worst case of the BBC scrambling for ratings I've ever witnessed. Never before have I seen them stoop so low to try and raise viewing figures. I was sat watching it waiting for the part where they offer the opposing view of the situation to allow people to make their own minds up, unfortunately however, that never came - it was one sided anti-wifi propaganda all the way through, from start to finish.
About the only attempt at offering an opposing view was the brief mention that the WHO states that there is no known risk of wifi at this time, this brief mentioning was followed by a couple of minutes of slagging off the credibility of the WHO.
I'm no expert when it comes to wifi, radiation and so forth and I'm not claiming that wifi is 100% safe - it may well pose risks. The problem with the program however seemed to be that it's entire argument is based on the premise that there is some other danger to human health from radiation other than the heating effect, and from what I've read elsewhere, there is absolutely no evidence that there is any effect other than the heating effect. I'm sure those with better scientific knowledge may be able to correct me on this if I'm wrong, but if it's true as has been reported by other news outlets (and in fact even by the BBC themselves online) then the majority of the program was fundamentally flawed in it's arguments.
What bothers me most is that we've gone from one lazy teacher looking for an excuse to get time off work claiming that wifi gives him headaches to a national wifi scandal. The worst part is that most reports that refer to the teacher in question who sparked this row ignore the fact that in scientific tests the teacher could neither a) tell whether wifi was on or off and b) now claims he gets these headaches wherever he is, even when not around wifi!
If Wifi does indeed pose a threat then I agree we need to do something, but thus far this seems equivalent to the whole terrorism/think of the children/drugs/computer games make people kill FUD.
Leukaemia (Score:5, Interesting)
My neighbours all have wireless, cordless and mobiles so I eventually turned all mine back on. Two years on and no-one else in the house, including my 2 other boys, have cancer.
Who knows what caused it. Live life to the full, make the kids smile and if low power wireless gadgets worry you, please get out more.
Trade one for the other (Score:5, Funny)
It's not the flight I'm afraid of, it's the notebook's landing that's the dealbreaker.
I changed my sig today [on-topic] (Score:4, Informative)
Unfortunately, in the UK at least, the number of scientifically trained journalists can probably be counted on one of Ben Goldacre's fingers.
Interesting that none of the phone mast posts seem to have remembered the inverse square law - sorry if you did and I missed you - which mean that radiation levels at the ground are a tiny fraction of what you get from the phone. And that nobody has mentioned all the radiation we used to get from TV and radio sets. As I recall, the radiation you get from an old tube superhet set (from the IF) is much more intense than the radiation from WiFi. It is lower frequency, but then the skin effect is less, and as anybody who ever played about with NMR will recall, VHF does things to organic molecules.
We'd better take action now. Let's get rid of all that nasty radioactivity - oops, Madam, there goes your granite kitchen work surfaces and your low-sodium salt. And all the radiation sources beginning with the most intense. So we've now turned off the Sun, mobile phones, radio, TV, electrical generating. We can't use coal (have you looked at what you get in the ash). So we can just sit in the dark and freeze.
As for the leukaemia cases - I have long believed that a far more convincing explanation is exposure to farm chemicals, pesticides, and the new virus and bacterial strains resulting from population movement. It is possible that farming overspray with chemicals which have been subsequently banned is a more probable cause of leukaemia clusters than, say, living near a rural electrical supply line. In the UK, and probably in the US too, the parts of Government which deal with farming tend to be extremely secretive and their decisions are often hard to understand. To my mind, they are far more likely to suppress information about such things than the relatively open parts of Government which deal with non-farming health and safety.
Re: (Score:3, Funny)
Re:Sounds familiar (Score:5, Funny)
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Kill bit (Score:5, Funny)
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Re:Sounds familiar (Score:4, Funny)
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Re:Sounds familiar (Score:4, Funny)
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Re:Sounds familiar (Score:5, Insightful)
I was attacking the position (hopefully with a little humour) that global warming is all FUD. That position seems untenable; that a large majority of the world's scientists would all conspire to promote falsehood. They may be entirely wrong, but the majority are in broad agreement.
Given that the consequences of not acting on this information may be disastrous, the precautionary principle suggests that we listen to them. Taken to its logical extreme, you would be advocating never acting on any scientific advice, as it *might* be wrong.
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To quote Lionel Hutz (Score:5, Funny)
Well, Your Honor, we've plenty of hearsay and conjecture. Those are kinds of evidence.
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Re:What's the Science in This? (Score:5, Insightful)
Maybe they read the article, which points out various scientists who argue that there IS evidence about it.
I've got to say, the ridiculously emotional backlash I see on
I personally don't believe cell phone signals or wifi signals are strong enough to cause health problems. But I'm certainly not going to be arrogant enough to proclaim that there absolutely are no health problems and we shouldn't even look at the problem.
I thought
Please, half of
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Re:What's the Science in This? (Score:5, Insightful)
One of them was about the dangers of black holes. They'll boil the oceans, suck the life right off the planet, there's a super massive one at the center of our galaxy, they feed and then they stay silent, drifting through space until WHAM. Lots of sound bytes of scientists saying "it's only a matter of time", "you can't see them, but we know they're there", "we have no idea how many there are", etc. In only 5 billion years our galaxy will collide with another one, and we might drift right into that galaxy's super massive black hole, etc, etc.
It's that sort of programming, and if they convince laypeople that more money needs to be spent on researching this than is really necessary it only does damage.
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Re:What's the Science in This? (Score:4, Funny)
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Re:FRAUD ALERT -- Slashdot sucked in again! (Score:4, Informative)
Different parts of the EM-spectrum probe different aspects of molecules. (Visible light probes electronic structure, infrared light interacts with molecular vibrations, etc.) Even the radiofrequency range of the spectrum interacts with molecules in a chemically-specific way: microwave-region EM-radiation probes the rotational modes of molecules, and radiofrequency spectroscopy can also probe nuclear states (see NMR [wikipedia.org]).
If I've misunderstood what you meant, please set me straight.
(By the way, I do agree that the energy from a WiFi signal will be absorbed by most common materials and lead to a barely noticeable increase in temperature. But that doesn't mean that the process is not chemical-specific. For instance, some materials will absorb more of the WiFi signal than others.)
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