Electromagnetic Fields

1. Introduction to electromagnetic fields

• 1.1 What are electromagnetic fields?
• 1.2 Why and how have the health risks of electromagnetic fields been reassessed?

1.1 What are electromagnetic fields?

Frequency ranges of 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 (with a frequency of 0 Hz). Static magnetic fields are used in medical imaging and generated by appliances using direct current. More...

Table 1. Typical sources of electromagnetic fields 

1.2 Why and how have the health risks of electromagnetic fields been reassessed?

It is well documented that, at certain frequencies, strong electromagnetic fields can cause specific reactions in living tissue:

• At frequencies up to about 100 kHz (in the ELF and IF range) – stimulation of nerves and muscles
• Above 100 kHz (in the radio frequency range) – heating of body tissue

These biological effects are immediate, and existing exposure guidelines, such as those issued by the International Commission on Non-Ionizing Radiation Protection (ICNIRP), have been established to protect against them.

However, the effect of long-term exposure to a low level of electromagnetic fields needs to be assessed, since low-level fields are omnipresent in our environment.

The review of relevant scientific reports was undertaken, with a focus on articles published after 2000, and the studies judged relevant are commented upon in the opinion. Areas where the literature is particularly scarce are pointed out, and an explanation for this scarcity is given.

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 the laboratory (experimental evidence). Based on this combined evidence, it 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. A full risk assessment also estimates to what extent the population is actually exposed and estimates the impact of exposure on public health. More...