Electromagnetic fields


Electrical and electronic systems have become so pervasive that it is now difficult to imagine life without them. While they contribute to our quality of life in many ways, they also create electromagnetic fields (non-ionising radiation) which, when emitted at sufficient levels, may warm biological tissues (as they do in microwave ovens).

Electromagnetic fields have different frequencies - expressed in Hertz (Hz), or oscillations per second - suited to different uses, for example:

  • strong magneto-static fields (0 Hz) are used in medical MRI scanning
  • low frequencies (50 Hz) are used by the standard alternating current (AC) electricity that supplies our homes and offices, power lines and household electrical appliances such as vacuum cleaners, hairdryers and irons
  • high frequencies are used by radios, televisions, mobile phones, Wi-Fi, microwaves, etc.

Until a few decades ago, the main man-made sources of electromagnetic fields were radio and television antenna and high voltage power lines. Since the 1990s, the rapid development of mobile telecommunications and other electronic appliances has substantially increased the sources and types of electromagnetic fields to which we are exposed. This has raised concerns about their possible adverse health effects.

The most common questions and answers  (also available in Japanese) on electromagnetic fields are summarised in a document prepared by the European Commission.