WiFi radiation? Is it dangerous for health?


by casanova
Tags: dangerous, health, radiation, wifi
casanova
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#1
Jul17-07, 10:54 PM
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an anybody explain the effect of electromagnetic signal emitted by wifi hotspot to our health? Is it dangerous?

sorry, i'm just being paranoid....
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russ_watters
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#2
Jul17-07, 11:10 PM
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No, it isn't dangerous. There is no mechanism known by which it could cause harm.
f3nr15
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#3
Jul18-07, 01:37 AM
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Quote Quote by russ_watters View Post
No, it isn't dangerous. There is no mechanism known by which it could cause harm.
Because E = hf says the energy of the emitted photons from the WiFi is of a safe 10-54eV ?

mgb_phys
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#4
Jul18-07, 12:19 PM
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WiFi radiation? Is it dangerous for health?


It's not the energy of the photons so much as the number of them!
Your microwave is at a similair wavelength ( and photon energy ) to a 2.4GHz wifi and that can do harm, similairly radar systems operating at much longer wavelengths (lower energies) can kill things.

The main difference is that the microwave puts out 800-1000Watts, radar puts out 10-100KW but the wifi base station only uses 0.1W.
casanova
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#5
Jul18-07, 07:40 PM
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Quote Quote by mgb_phys View Post
It's not the energy of the photons so much as the number of them!
Your microwave is at a similair wavelength ( and photon energy ) to a 2.4GHz wifi and that can do harm, similairly radar systems operating at much longer wavelengths (lower energies) can kill things.

The main difference is that the microwave puts out 800-1000Watts, radar puts out 10-100KW but the wifi base station only uses 0.1W.

So basically it's not dangerous because of its low power, right?... but I'm still aware of the long term bad effects it can have....
mgb_phys
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#6
Jul18-07, 07:50 PM
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Correct, if you are worried about high power microwave energy stay away from the big yellow thing in the sky - it puts out an awful lot more than your wifi hub.
chroot
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#7
Jul18-07, 08:01 PM
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Of all the things you should or could be concerned about, the radiation from your WiFi transmitter is near the bottom of list. There are literally thousands of things that verifiably have a much larger potential to impact your health.

To start with, you should be much more concerned about your diet, the amount of exercise you get, the kind of health care you recieve. I'd even be more concerned about the kind of dyes in my clothing, the kind of plastics used in my home, and how slippery my bathroom floor is than about my exposure to minute quantities of non-ionizing EM radiation from my WiFi transmitter.

- Warren
mgb_phys
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#8
Jul19-07, 01:16 PM
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You can't of course say anything is perfectly safe - this is a point jumped on by journalists writing scare stories.
In looking at radiation doses there are two considerations - how effectively the energy is absorbed and how much energy is delivered.

The amount of absorbtion depends on the sensitivity of the tissue and how effectively it absrobs a particular frequency.
Consider your eye, it can be damaged by a very low power 2mW visible laser because it is particulalrly sensitive and strongly absorbs visible light. An infrared laser of 20mW would do no damage because your eye doesn't absorb it so well. A 200mW laser on your hand would do no damage because the tissue isn't so sensitive.

With the wifi signal or any radio wave you have to consider, is the wavelength such that it is strongly absorbed by a particular tissue - so that a smaller power can do more damage than you would expect. Or is it just the heating effect - in which you can easily show that 100mW isn't enough to cook you.
Some of the legitimate concerns about mobile phones come from the suggestion that the wavelength is about the right size to fill your skull and so could put more heat into your brain than if the same power was just on your skin. Mobile phones are rather higher power than wifi and usually pressed to the side of your head.

You can try and show they are safe by either considering all the mechanisms that might cause damage and calculate that the power is too low - but there might be unknown physiological effects that perhaps a small amount of heating in a certain tissue can do more damage than you expect.
Or you can do studies that look at death rates in real people over long periods - the problem is finding exactly equivalent people that only differ in the thing you are studying.
Suppose you compare death rates over 20years in Wall St traders using mobile phones every day with buddist monks eating a vegitarian diet and doing yoga continually - would you assume that the difference in their health was solely due to mobile phone use?

(There was a famous study on VDU radiation in sweden - it bank compared bank traders with farmers in an Amish like sect that didn't have electricity. The conclusion was that VDUs caused misscarriages!)
dtsormpa
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#9
Aug15-07, 04:39 AM
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All EM emmiting devices have at their specifications a SAR number (this stands for Special Absorbsion Rate = the Rate that unit mass absorbs radiation). There are standards that make manufacturers design their products at specific and especially low SARs. SARs are different depending the age, so each EM emitting device must fullfill these specifications for ALL ages of population. Bottom line: there is no danger what-so-ever.
mgb_phys
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Aug15-07, 03:02 PM
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A bit of a circluar arguement, they are safe because they are built to safety standards and the safety standards are the levels we say are safe!

But I agree, I'm not worried about my wifi - I did hurt my back quite badly once falling over a wired cable.
Danger
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Aug15-07, 06:12 PM
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Who was it once said "Microwaves can frizzle your heir"?
Sensible
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#12
Jan1-09, 09:49 AM
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Hi
WiFi uses a frequency of 2.45Ghz.
Data is sent in 'packets' or 'pulses' along the waves.
It is this 'pulse' that many scientists think is responsible for the mechanism for adverse health effects that are being reported in the scientific literature.


Although the intensity is 'low' it is still trillions of times above the natural background levels in that part of the electromagnetic spectrum.

The ICNIRP guidelines are intended to protect in the very short term against gross heating effects.
These take no account of any other 'biological' effects as a result of long term exposure to which many people are now subjected.

Please take time to read the science which is largely being ignored by the main stream media. The evidence dates back decades.

This site has been set up by some UK scientists
http://www.wifiinschools.org.uk/

This site has many scientific papers
http://www.hese-project.org/hese-uk/...content_type=R

Two good meta anlyses by independent scientists are
http://www.hese-project.org/hese-uk/.../ecologsum.php
and
http://www.bioinitiative.org/press_release/index.htm
Vanadium 50
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#13
Jan1-09, 12:13 PM
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First, your sites are hardly "independent" - they all push an agenda. They also admit a gross ignorance of electricity and magnetism. From hese-project: "Electricity is a wonder and a convenience. But we still understand it only very partially. How it behaves, where it flows, how it mixes, ‘what’ it is, are still quite elusive, despite the complex mathematics from James Clark Maxwell onwards that ‘explains’ it."

While I am certain that they don't understand it, it's not true that nobody understands it.

Second, as Paracelsus said, Alle Ding sind Gift, und nichts ohn Gift; allein die Dosis macht, daß ein Ding kein Gift ist, that is, "the dose makes the poison". Too much vitamin A and you die. That doesn't mean that it's dangerous in low doses - in fact, too little and you die. So tossing lots of studies where exposure is many orders of magnitude greater is irrelevant. It makes good scaremongering, but lousy science.

There is neither evidence for nor a plausible mechanism for danger from low levels of RF.

Now, onto the "packets" and "pulses". Ethernet does have "packets", but that doesn't mean that the WiFi transmitter is sending them like Morse code by rapidly turning on and off. WiFi uses something called phase shift modulation: you have a continuous signal transmitted, and the 1's and 0's are encoded by shifting the phase. So if it were true that "it is this 'pulse' that many scientists think is responsible for the mechanism for adverse health effects that are being reported in the scientific literature" (which I doubt), you would have just proven that WiFi is safe, since it doesn't work this way.


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