Limits for electromagnetic fields
- Protection of sick persons, children and pregnant women -
Basic limit values
The International Commission on Non-Ionizing Radiation Protection (ICNIRP) has recommended the introduction of a basic limit value for the general population.
The basic limit value is 50 times lower than the level above which an effect occurs. With this very low value, the independent commission of scientists wants to ensure that vulnerable people, such as sick persons, children and pregnant women, are protected (Report of the Commission on Radiological Protection, No. 23, Appendix 6).
For practical reasons the resulting basic limit values – a whole-body SAR value of 0.08 W/kg and a partial-body SAR value of 2 W/kg averaged over 10g of tissue – were converted into limit values that are easy to calculate. These limit values are enshrined in the 26th Ordinance on the Implementation of the Federal Immission Control Act (26th BImSchV) (Bundestag document 393/96, p. 15 seqq.).
These limit values are based on recommendations by national and international bodies, such as the ICNIRP, the World Health Organization (WHO) and the Council of the European Community which carried out risk assessments on the basis of a series of scientific studies.
The German Commission on Radiological Protection (SSK) examined the limit value in 2001, and again between 2002 and 2008 within the framework of the German Mobile Telecommunication Research Programme. The outcome: There is no evidence that would require the revision of the current limit values.
The legislation contains a series of rules to protect the population from electromagnetic fields. These rules were developed on the basis of limit values that are, in turn, based on international and national research.
There is scientific evidence that high-frequency electromagnetic fields have a thermal effect on the human body, which is why the electromagnetic field energy in the body tissue is used to determine the limit value. Watts per kilogramme of body weight (W/kg) is the unit used to calculate the specific absorption rate (SAR).
If an electromagnetic field affects the whole body, e.g. in the far field region of a base station, the total absorption is averaged and calculated over the whole body. The SAR value of the whole body is expressed in watts per kilogramme of body weight; this is also called the whole-body SAR value.
When a person uses a terminal device, an electromagnetic field affects a very limited part of the user's body. The energy absorbed is determined by calculating the partial-body SAR value. "An above-average temperature increase does not cause adverse health effects – provided that nowhere in the body the temperature rises by more than 1°C as a result of the absorption process. Even under unfavourable conditions and at a partial-body SAR value of 10 W/kg, no harmful effects can be observed" (Bavarian Environment Agency, Elektromagnetische Felder durch Mobilfunk, 2012, p. 22).
In Germany, the limit values are defined in the 26th Ordinance on the Implementation of the Federal Immission Control Act (26th BImSchV). They comply with the recommendations of the WHO, the ICNIRP and the Council of the European Community.