Electric and magnetic fields (EMFs) are part of the natural environment and are present in the earth’s core and atmosphere. These fields are also produced wherever electricity or electrical equipment is used.
All electrical appliances such as computers, televisions, hair dryers, electric blankets and clock radios produce EMFs (including ‘standby’ modes), as does the electrical wiring in any home or building.
Electrical energy involves ‘voltage’, which is the pressure behind the flow of electricity that produces an electric field, and ‘current’, the quantity of electricity that produces a magnetic field.
At extremely low frequencies such as power frequencies, EMFs do not normally radiate from their source. They merely exist in the space surrounding their source and the strength of the fields decrease rapidly with distance from their source.
On the other hand, at much higher frequencies such as radio frequencies, energy is radiated away from the source and can be detected at great distances. Other familiar examples of radiating fields are television signals, microwaves and sunlight. It is for this reason that power frequency EMFs are described as ‘fields’ and not ‘radiation’.