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University Bans wi-fi as Health Concern
BaltikaTroika writes "A Canadian university has banned wi-fi, since the university President sees a possible link between electric and magnetic fields and brain tumors. According to the head of the university, "the jury's out on this one, I'm not going to put in place what is potential chronic exposure for our students." Is anybody outside of this university's administration concerned about this?"
Gee, where have we all been hearing THAT phrase lately?
Fact: Nobody has ever demonstrated in a repeatable, peer-reviewed, properly-controlled study that low-level RF radiation at nonionizing wavelengths has any biological effect whatsoever. For every study that shows correlated effects, two more show none at all.
Fact: WiFi adapters, even the gray-market 100 mW jobs you buy on eBay, transmit 1/10 to 1/100 the power of a cell phone.
Fact: Your microwave oven leaks more 2.4-GHz energy than your WiFi card emits intentionally. For best results, cut a 1" slit in package wrapper and rotate dish after 2 minutes on HIGH.
Fact: DNA damage from 2.4 GHz radiation at athermal levels would require a form of matter-energy interaction that is currently unknown to physics. There's a guaranteed Nobel Prize for anyone who can document such an interaction, because as far as anyone knows, we pretty have all the fundamental interactions covered at this point. Get cracking!
(Probable) fact: This joker has some sort of financial interest in a local commercial ISP whose business would be threatened by a campus-wide network. Nobody that stupid runs a university... but conflicts of interest aren't exactly unheard-of in that line of work, are they?
Quick lesson: EM field from a point source: 1/r^2 strength EM field from a line/wire (theoretically infinite): 1/r strenth EM field from a plate (theoretically infinite): constant strength The derivations involve many repulsions and attractions of charges as you integrate along an entire line or plane. This is stuff you should know after learning multivariable calculus.
A guy walks into a bar... well, I forgot the joke, but the punchline is that he's an alcoholic.
Maybe old analog phones. Modern digital phones are rated at a maximum output of 200 milliwatts. I've read that the typical output is somewhere between 1 milliwatt and 5 milliwatts. I've studied more about CDMA phones than other technologies, and I think they adjust the output power every 40 milliseconds, based on the signal strength of the receiver (tower).
What's the typical power output of a cordless phone in the house? I'm guessing it's more than 5 milliwatts.
I'd suggest taking a look at CNET's cell phone radiation chart. Updated Feb 22, 2006.
[quote]
"well that's ok, because the study was about Electromagnetic fields, not magnetic
fields, which are two different things. As far as I am aware, there is absolutely nodanger to humans from a magnetic field."
[/quote]
Wrong. All Electric and Magnetic Fields are the same thing. They are components of the same EM field Tensor.
F_mu_nu=del_mu(A^nu)-del_nu(A^mu)
Where A is the 4-vector Potential (ie the scalar potential & the regular magnetic vector potential).
All quantities here are 4-vectors/tensors with a Minkowskian metric:
g_mu_nu=diag(1,-1,-1,-1)
F has 6 independent components, 3 being the electric field components, 3 being the magnetic field components.
The above expression, together with Maxwell's Equations:
del.F=J
del~.F=0
are manifestly Lorentz Covariant equations, meaning they are invariant under a Lorentz Transformation. This means that, since the lorentz transformation is unitary, & can be written as:
F`=L_dagger*F*L
this will leave Maxwell's equations unchanged. Thus, if you have a pure magnetic field (like that of the earth) with the 3 E's in F being 0, it is always possible to construct an L st F` has nonzero E's. L is a Lorentz Transformation, so the physical significance is that you can always transform relativistically to a frame of reference where a magnetic field picks up an electric field and even radiation EM fields (such as Lienard-Wiechert potentials), making it an "electromagnetic" field.
l'Homme n'est Rien l'Oeuvre Tout: Gustave Flaubert to George Sand
There is a widely discussed problem called electrosensitivity, or ES. Thousands of people suffer from it. However, searching the internet, I can find no articles on it other than conspiracy sites that claim that millions of people are affected, and the government and medical industries keep it secret because they love their cellphones. In fact, while these website site all of these journal papers and conferences on the subject, there references appear to be completely fabricated to make them seem plausable. The only actual scientific articles have asserted that such a syndrome does not exist. Several groups in the UK and the USA have conducted double blind tests in which sufferers are secretly exposed to EMR of frequencies like that they claim cause their symptoms (Monitors, cell phones, etc), and they did not react. On the other hand, when exposed to a radio device they are told is active, but which is nothing more than a box with a light, they react immediatly. These studies are dismissed by the ES campaign groups, who declare they are secretly funded by the cellphone companies. Some even declare that all scientiests are against them because scientists love computers and other electronic gadgets, and all scientists will forever bury the mounds of evidence.
ASCII stupid question, get a stupid ANSI
This guy's obviously a bafoon, but he's got half a point (misdirected, but still...). I think we all know the link between mobile phones and cancer (despite what the telcos say). There's also a suspected link between mains electricity (and it's associated fields) and cancer:
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http://www.telegraph.co.uk/news/main.jhtml?xml=/n
So the point being, the frequency is irrelevant, it's all to do with the magnetic and electric fields. When one or both of these are far in excess of ambient, they cause problems.
The new-age movement goes further to infer that all electrical devices give off 'bad vibes' in the form of positive ions (which make you feel tired, depressed etc). Clearly, transmitting devices are designed to propagate a signal, so it follows that they create more of these ions. Again, there's some science behind this, although arguable.
It looks like this guy is a bit misguided, but looking out for such things. For it to be any use at all, he'd have to ban phones, high current cables, and most of the engineering department, oh, not to mention around about every computer on campus.
Joule-seconds...That's the dimension of Planck's constant - not meters-squared-kilogram per second
They are equivalent:
Joule -> kg m^2 / s^2
Plank's constant = h
Frequency of EM radiation = f -> 1/s
photon energy (Joules) = h * f
Since the unit of f is Hz or 1/s, Plank's constant can be represented with the units J*s or equivalently kg m^2 / s.
QED
Ceci n'est pas une sig.
I see a lot of wannabees rant about this university being run by unscientify crackpots. And that the sun and radio and tv is more radiation blah blah ... :-) . Her life isn't that fun though. When her neighbor above leaves his 20" CRT on she can't sleep. She's got other trouble with that aswell and people often don't believe her and think she's crazy.
I've got news for you: Microwaves damage health. Period.
The debate is at which intensity do they start doing that.
I generally turn my Wifi of if I'm not using it and have stopped carrying my cellphone close to my body, since it's on all day. I turn it off at night. I also hold it away from my head when I make a call until the cell handshake is over and the remote connect is there. My Siemens M35 even has a beep to indicate when the connect is there. Smart people the Siemens engineers, aren't they?
Handshake you ask? That's the high-power meep-meep-meep you hear in nearby active FM radios just before you make or recieve a call. It's what establishes the conection to the cell network for communication. I even know a woman who can sense the cellphone handshake (she has e-magnetic field sensetivity) from meters away and has the habbit of anouncing cellphone calls seconds before a phone rings. Fun to watch with unsuspecting others near by
On it goes:
My father was a high profile radar electronics engineer - with Military (Nato, Cruise Missile), Airbus, Nasa/Grumman Aircraft (Lunar Module, Space Shuttle, etc) and some others. He forbid us to have a Microwave oven (they ALL leak Microwaves) and steared clear and went the other way whenever we got to close to a radar bubble when going hiking.
There are people who've had terminal brain tumors due to intense cellphone usage and I work with doctors (medical IT) who keep all equipment far away and well cased according to TCO.
Bottom line:
Don't think it's not unhealthy just because most people don't care. A little common sense and forsight is needed when handling technology. You don't get universal flawless wireless conectivity without a tradeoff. Anyone who believes that is a crackpot himself.
We suffer more in our imagination than in reality. - Seneca
I can't speak to this ES phenomenon, nor your anecdotal argument, but it was documented in 2003 - and hasn't been successfully challenged by any new research, to my knowledge - that cell phone radiation seriously injures the blood brain barrier in rats. This was found to be the case for radiation levels similar to those found in modern cell phones.
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