is EMI really dangerous?

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Offline moccacake

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is EMI really dangerous?
« on: 18/05/2006 20:10:38 »
does anyone know if electromagnetic interference is really dangerous to humans?



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Re: is EMI really dangerous?
« Reply #1 on: 18/05/2006 21:14:41 »
EMI is just EM that happens to be in an environment where it interferes with something else.

To ask whether EM is dangerous, it depends on the frequency and power of the EM.

EM can include mains frequency (50/60Hz), through MW and VHF radio, through microwave, to light to ionising radiation such as X and gamma rays.

Clearly, ionising radiation is more dangerous for a given power than mains frequency radiation, thus X rays, for all their therapeutic and diagnostic value, are carcinogenic.

Light can be dangerous, but since we have so much of it around, the human body has learnt to tolerate, and even gain benefit, from normal amounts of light.  Too much UV is clearly a danger, but then so too is too little.

Lower frequencies (infra red and radio waves) can cause burns and overheating if you get too much of them (toasters and grills use infra red, and microwave ovens use 2GHz microwave radio).

Even MW radio waves, if you get several kilowatts of power is close proximity, can cause burning of the skin, but so long as you are not actually a few inches away from the antenna of a commercial broadcast transmitter, this is unlikely to be an everyday problem..

As one gets lower down the frequency range, such as mains frequency, there is no recorded effect adverse short term effect, although there is still controversy about whether there may or may not be a long term effect if you are subject to sustained exposure.  No controlled experiment has shown any such effect, but the issue remains that there are some people who believe they have anecdotal observations that are contrary to the results of the controlled experiments.