Electromagnetic field spectral evaluation problems in exposure assessment.

Electromagnetic fields have become an omnipresent factor in our daily environment. It has become common that the exposure situations are characterised by a cocktail of spectral contributions from different sources, while exposures to single frequencies are rare. Thirty-two different types of drilling machines were analysed. Even similar devices exhibited large variations of emission levels up to two orders of magnitudes. It was found that emissions are not negligible and could be close or even above reference levels. Already single spectral peaks of magnetic emissions may considerably exceed reference levels, and excess can reach even the 90-fold when evaluating the entire spectrum. It is shown that approaches to assess complex frequency spectra as proposed by the International Commission on Non-Ionising Radiation Protection or defined in compliance standards issued by CENELEC or IEC lead to contradictory conclusions on conformity or non-conformity. There is an urgent need to clarify this discrepancy.