Biological effect of electromagnetic wave 　
　

Biological effect of electromagnetic waves has been investigated for more than 30 years, and safety guidelines has been published to protect people against excessive exposure of electromagnetic waves depending on the frequencies. A few years ago, new guidelines for the use of mobile phones were published.

 　


Sunshine causes sun burn, long time exposure may cause skin cancer.
Clothes and glasses are enough for protection.
As a laser beam is focused to a point on the retina and may damage it, it is used under regulations.
In public area, laser beams are used under the strict safety regulations.

If resonance occurs, the body behaves like an antenna.

High frequency electromagnetic waves give influence only on the surface of the body.
Low frequency waves tends to penetrate into the body.
The electrostatic shock is harmless.
Power line in a house gives a harmful shock.