Electromagnetic radiation is the set of radiations that transfer energy in the form of electromagnetic waves, i.e. local and temporal changes of the magnetic and electric field. Most of the electromagnetic fields that we are exposed to are man-made (artificial), but some come from nature (naturally). The most widespread and permanent natural electromagnetic field is the magnetic field of the earth itself, which exists everywhere on the planet and in space. Although the earth's magnetic field is all around us, it has very low power, only about 500 milligauss. In general, radiation affects the human body in a complex way, sometimes beneficial and sometimes harmful, depending on the type, intensity and energy.
Electromagnetic fields appear in a wide range of frequencies (electromagnetic spectrum) divided into sub-regions (frequency bands). The frequency range includes ionizing and non-ionizing radiation. The sources of electromagnetic fields, which affect a large part of the population every day (radio waves, microwaves, electricity) and belong to the category of non-ionizing radiation, are shown in the figure below.