1. Introduction to electromagnetic fields
- 1.1 What are electromagnetic fields?
- 1.2 How have the health risks of electromagnetic fields been reassessed?
1.1 What are electromagnetic fields?
Electromagnetic fields are a combination of invisible electric and magnetic fields of force. They are generated by natural phenomena like the Earth’s magnetic field but also by human activities, mainly through the use of electricity.
Mobile phones, power lines and computer screens are examples of equipment that generates electromagnetic fields.
Most man-made electromagnetic fields reverse their direction at regular intervals of time, ranging from high radio frequencies (mobile phones) through intermediate frequencies (computer screens) to extremely low frequencies (power lines).
The term static refers to fields that do not vary with time (i.e. with a frequency of 0 Hz). Static magnetic fields are used in medical imaging and generated by appliances using direct current. More...
|Frequency range||Frequencies||Some examples of exposure sources|
|Static||0 Hz||video display units; MRI (medical imaging) and other diagnostic or scientific instrumentation; industrial electrolysis; welding devices|
|ELF [Extremely Low Frequencies]||0-300 Hz||power lines; domestic distribution lines; domestic appliances; electric engines in cars, trains and tramways; welding devices|
|IF [Intermediate Frequencies]||300 Hz - 100 kHz||video display units; anti-theft devices in shops; hands-free access control systems, card readers and metal detectors; MRI; welding devices|
|RF [Radio Frequencies]||100 kHz - 300 GHz||mobile telephones; broadcasting and TV; microwave ovens; radar and radio transceivers; portable radios; MRI|
1.2 How have the health risks of electromagnetic fields been reassessed?
The review of relevant scientific reports was undertaken, with a focus on articles published in 2007 and 2008, and the studies judged relevant are commented upon in the opinion. Areas where the literature is particularly scarce are pointed out, and an explanation is given why the results of certain studies do not add useful information to the database. This assessment evaluates both potential effects on groups of people who have been exposed to electromagnetic fields in their daily lives (epidemiological evidence) and potential effects observed in laboratory experiments carried out on human volunteers, animals, and cell cultures (experimental evidence).
Based on this combined evidence, the assessment estimates whether there exists a causal link between exposure to electromagnetic fields and some adverse health effects. The answer to this question is not necessarily a definitive yes or no, but expresses the weight of the evidence for a link between an exposure and an effect. If such a link is found, the risk assessment estimates how strong the health effect is and how great the health risk would be for different exposure levels and exposure patterns (dose-response relationship). The nature and the extent of uncertainties are highlighted and the way in which electromagnetic fields might cause effects (plausible mechanism) are evaluated. More...