The effects of electromagnetic fields on human beings are well known today. This statement is valid both for the low-frequency electric and magnetic fields of power supply systems and for the high-frequency electromagnetic fields used in mobile telecommunication systems.

The documented health effects of such fields only occur if certain field intensities are exceeded. The legal limits as set out in the 26th Ordinance on the Implementation of the Federal Emission Protection Law (Ordinance on electromagnetic fields – 26th; BImSchV; in force since January 1st, 1997) for fixed and commercially applied low-frequency (e.g. high-voltage power lines) as well as high-frequency installations (e.g. mobile phone base stations) prevent such health effects.

It is impossible to prove that health related risks do not exist at all by scientific means. However, science can characterize the likelihood of adverse health effects. It is always possible that there are risks which up to now are not fully apprehended by scientists.

Moreover there still exist uncertainties regarding risk evaluation for high-frequency electromagnetic fields that could not be completely resolved by the German Mobile Telecommunication Research Programme. Regarding possible health risks when using mobile phones for more than 10 years data are not sufficient for a final conclusion. Mobile telecommunication is an emerging technology and brain tumours have a long latency. The number of persons using their mobile phone for more than ten years is too low to provide statistically reliable data. The question if children are more exposed or more sensitive to high frequency electromagnetic fields than adults remains open. Within the German Mobile Telecommunication Research Programme numerous conceivable study designs were pursued. However, current data are not sufficient to provide conclusive answers to the question on possible health risks for children and adolescents.

For low-frequency magnetic fields there is consistent evidence for a possible health risk from epidemiological studies (see “Biological and Health Effects of Low Frequency Electric and Magnetic Fields”). This empiric information has led the WHO to categorize low frequency magnetic fields as possible carcinogenic for humans.

To deal with such uncertainties, prevention from known risks through limits has to be complemented by precautionary measures.

For the Federal Office for Radiation Protection (BfS) precautionary measures are important and appropriate in view of the existing scientific uncertainties regarding the potential risks of electric, magnetic, and electromagnetic fields. An important aspect of precaution is to reduce exposure of the public to electromagnetic fields both by lowering the field intensity and by reducing the duration of an exposure. Other precautionary measures are to intensify research in order to reduce scientific uncertainties and to broaden the current state of knowledge as well as providing information and education to the public. These two tasks are performed by BfS.

Everyone has the chance to minimise the effects of low-frequency electric and magnetic fields as well as of high-frequency electromagnetic fields individually.

– Keep a distance

The intensities of both low-frequency and high-frequency fields decrease strongly in most cases when the distance to the field source is increased. So keeping a further distance is a simple method which often helps to clearly reduce exposure. Examples for specific measures are: do not place mains-operated clock radios close to your bed-head; install the baby monitor at least one metre away from your baby, place the power supply unit as far away from your baby as possible.

– Reduce the duration of exposures – switch off standby sources.

A lot of devices are not switched off or left on standby even when they are not used. This behaviour does not only lead to wasting energy but it also leads to produce magnetic fields that could be avoided as a precautionary measure.

- Use radiation reduced appliances.

For some appliances there is information concerning EMF emission available from the manufacturer or on the internet; for cell phones and cordless telephones (DECT phones) for example at http://www.bfs.de/en/elektro. For cell phones and baby monitors an environmental label (Blauer Engel) exists. For cell phones, however, it is not really used by the manufacturers. On the basis of information on the SAR value available at the internet users can choose a mobile phone with low radiation levels.

The high-frequency electromagnetic fields which are produced when using mobile phones are often much stronger than the fields people are exposed to from mobile phone base stations in their vicinity. Therefore, BfS considers it especially important to minimise as far as possible the fields mobile phone users are exposed to. The following recommendations may be helpful:

• Use a fixed network telephone if you have the choice between using a mobile phone and a fixed network phone.
• Send text messages.The mobile phone is in greater distance from the head and the fields the head is exposed to are lower.
  
• Only make short calls with your mobile phone.
• Preferably do not make phone calls if the reception is poor. The mobile phone's transmitting power depends on the quality of the connection to the next base station. The car body e. g. can affect the connection so that the mobile phone's transmitting power is increased.
• Use a mobile phone with a low SAR value which exposes the user's head to rather low fields. The smaller the field intensity, the less energy is deposited in the human tissues. Information is available from the manufacturers or at http://www.bfs.de/en/elektro/oekolabel.html.
• Use mobile phone headsets. The field intensity decreases strongly with the distance to the antenna. A headset serves to increase the distance between the head and the antenna of the mobile phones so that the user's head is exposed to lower fields during phone calls.
• Wait until the connection has been established. The GSM mobile phone uses maximum transmitting power while connecting. Do not hold the mobile phone to your ear while you are waiting for the connection to be established. In contrary the new UMTS mobile phones start with minimum transmitting power and increase it if necessary.