What are they?

In physics, a "field" is the zone of space where forces are manifested. For example, the gravitational field is the zone where there is a gravitational force responsible for giving bodies a determined weight. An electromagnetic field is a zone where electric and magnetic fields exist, created by electrical charges and their movement, respectively.

Electric and magnetic fields, available in spanish

Electromagnetic fields occur naturally in our environment and our organism is accustomed to living with them throughout our lives: for instance, the Earth's natural static electric and magnetic field, the X-rays and gamma rays from space and the infrared and ultraviolet rays emitted by the sun, not forgetting that visible light itself is an electromagnetic radiation. In addition, we are subjected to numerous types of electromagnetic fields of artificial origin, such as the radio frequencies used in mobile telephony, radio and television waves, anti-theft systems, metal detectors, radars, remote control units, wireless communication, and so on.

All of these form part of the "electromagnetic spectrum" and are differentiated by their frequency, which determines their physical characteristics and therefore the biological effects they can produce on bodies exposed to them. At very high frequencies, the energy transmitted by an electromagnetic wave is so high that it can damage the genetic material of the cell (the DNA) and initiate a carcinogenic process, as in the case of X-rays. The radiations situated in this zone of the spectrum are known as "ionizing".

However, the electrical system functions at an extremely low frequency (50 Hz to 60 Hz in the USA, called "industrial frequency") and lies within the region of non-ionizing radiations of the spectrum, which means that it transmits very little energy. Moreover, at such low frequencies the electromagnetic field cannot travel in space (as, for instance, radio waves do),which means that it disappears at a short distance from the source that generates it.

Frequency spectrum. (pdf.436KB) Open in new window