Different basic dosimetric quantities for the characterization of exposure to low-frequency electric and magnetic fields and the implication for practical exposure conditions and guidelines.

In this paper, the different quantities for characterizing human exposure at extremely low frequencies (ELF) up to 100 kHz are described. It is explained how the incident field is disturbed by the human body and how the in-situ fields and current densities are created in the body. Incident electric and magnetic fields are treated separately. Incident field characteristics such as homogeneity, time dependence, and polarization and body characteristics such as dimensions, shape, and position will influence the induced quantities. The use of in situ fields or of induced current densities to set the basic restrictions is discussed. The methods for deriving the reference levels from the basic restrictions in the international standards such as ICNIRP and IEEE guidelines are mentioned. Elliptical human models have been typically used in the past. In recent years, high-resolution anatomical models have become available. In this case maximum induced field levels or current densities can be determined for each organ. The validity of using elliptical or high-resolution anatomical models to derive reference levels is discussed. Special attention is paid to non-uniform (such as domestic exposure) or partial exposure of the human body.