[Hygienic assessment of sources of electromagnetic fields using revised and new standards of maximum admissible intensities]

Abstract

In 2001, the legal regulation on maximum admissible intensities (MAI) of electromagnetic fields (EMF) in the frequency range of 0-300 GHz was amended. In the existing regulation, the ranges for frequencies between 0 and 50 Hz and between 50 Hz and 1 kHz were not defined, and for the frequency of 50 Hz there were no regulations for the electric component. The amended regulation expands the obligation to measure and assess the magnetic component up to 3 GHz (formerly to 10 MHz only) and moderates the admissible level for extremities at the frequency below 800 kHz (magnetic component). In addition, the MAI values are thoroughly verified in the whole range of standardized frequencies. Formally, all kinds of power supplied equipment are the source of EMF. In practice, the measurement of all equipment and installations is not feasible or justified. According to the Database by the Chief Sanitary Inspector, the number of EMF sources recorded by the sanitary inspection in 2002 exceeded 60 thousand. Therefore, it was found advisable to analyze the results obtained from the studies of occupational exposure to EMF after the introduction of new MAI'2001 to select equipment and to find out whether equipment and installations generating EMF corresponding at most with protective zone needs to be controlled. The analysis covered 9 thousand of equipment and installations of various types (data collected by the Central Database on EMF sources and our own data), in particular EMF sources: strong EMF with endangered protective zone and non-identified levels of generated EMF; weak EMF but responsible for chronic exposure; and EMF sources occurring in large quantities in places where people work or have to stay longer (e.g., hospitals, treatment rooms, production halls). The analysis facilitated the hygienic evaluation of the equipment and installations according to MAI'2001. In all, 49% of equipment were found not to be the source of EMF with values from protective zones, and thus it is obvious that their control is not justified as exposure does not occur or in case of occupational exposure it can be neglected. The authors present a long list of equipment and installations with the maximum levels of generated EMF. The level of generated EMF was assessed according to the criterion of protective zones: intermediate, hazardous and dangerous.