Exposure analysis, exposure assessment and current data on the exposure of the general public

What is the issue?

The assessment of possible health risks due to low-frequency electric and magnetic fields relies on very precise knowledge of the exposure of those affected. To what degree are they exposed to low-frequency fields from power lines and other sources, such as electric household appliances? How are the field strengths distributed over the various tissues and organs in the body that are known to react differently to accordingly high field strengths? On the one hand, this subject area therefore focuses on questions relating to daily exposure and to measurement procedures for electric and magnetic fields. On the other hand, it deals with procedures that allow better determination of field strengths inside the body, where direct measurements cannot be taken, than was possible in the past.

What is the current situation?

The exposure of humans to low-frequency electric or magnetic fields leads to the generation of electric fields and currents within the body. How the electric fields are formed and distributed in the body depends on the electric and dielectric properties of the respective body tissues. So far, insufficient research has been carried out into these properties for the various types of tissue. Likewise, there are only a few studies on the occurrence of spark discharges and contact currents, which occur more frequently below high-voltage power lines. Furthermore, common measurement techniques and devices currently only allow limited measurement of the strength of electric fields around high-voltage overhead lines (direct and alternating current) or are insufficiently accurate.

What are the objectives of the BfS research projects?

The research projects are aimed at improving the availability of data relating to:

• the generation of electric fields and currents in the body. This will involve improving existing dosimetric models.
• the actual occurrence of contact currents and spark discharges in the vicinity of power lines.
• the more accurate measurement of electric field strengths emitted by high-voltage power lines. This will involve testing new measurement techniques and equipment.
• the average exposure of the German population to magnetic fields. Among other things, this will involve determining the contributions of various sources to the total exposure.