Electric and Magnetic Fields are induced outdoors among others by powerlines or antennas.

Indoors, the many electrical or electronical devices used at home may generate these fields.

Some Standards recommend threshold levels above which a long exposure should be avoided for health reasons:

• such as 10 V/m for the Electric field,
• such as 2 mG for the Magnetic field.

A cartography of the Electromagnetic field can be carried out with calibrated devices and expressed under official reports, e. g. Magelan+ by PSO.