Electromagnetic fields - Limit values - WHO

Electromagnetic fields (EMFs) are omnipresent components of the environment, originating from both natural and human-made sources. Natural EMFs include electric fields generated by atmospheric charge accumulations during thunderstorms and the Earth's magnetic field, which serves biological navigation functions for species such as birds and fish. Artificial sources encompass medical devices utilizing static fields, for example, magnetic resonance imaging (MRI), household appliances emitting low frequency electric and magnetic fields at 50/60 Hz, and multiple wireless, telecommunication, and broadcasting technologies that operate within the high radiofrequency spectrum ranging from 100 kHz to 300 GHz. EMFs contribute significantly to advances in quality of life, health, and well-being when applied appropriately. However, at elevated intensities, electromagnetic fields can adversely affect human health, with physiological impacts varying according to the frequency of exposure. Consequently, international and national standards have been established to regulate exposure limits to EMFs. These standards differentiate between static, low-frequency, and high-frequency fields, employing metrics such as magnetic flux density (µT), electric field strength (kV/m and V/m), power frequency (Hz), power density (W/m²), and specific absorption rate (SAR in W/kg). Legislative measures globally reflect these standards to ensure public safety by limiting exposure to EMFs within scientifically determined thresholds. Continuous monitoring, research, and regulation are essential to balance the beneficial uses of electromagnetic fields with potential health risks, underpinning policies that address their control and permissible exposure across various frequencies and applications.