Variability of Environmental EMF and New Technical Possibilities for Recording in Time-domain and Assessment of Exposure Level - New Challenge for Biomedical and Epidemiological Studies

Abstract

P-541 Introduction: The majority of population is subject to simultaneous exposure to electromagnetic fields (EMF) from broadcasting and power distribution installations, as well as various electrical appliances. The classical assessment of EMF's exposure is based on the results of spot measurements of current value of electric or magnetic field strength from selected frequency range. In most cases low frequency/50 Hz or radio/microwave are taken into the consideration separately. Modern EMF's measurement devices offer the possibility of more detailed investigations of exposure parameters. Methods: Presented data were collected mostly from the detailed analysis of exposure of workers to EMF's which exist in transport (cars, trams, metro, etc.), in offices and from welding devices. measurements were carried out in poland, mostly in urban area of Warszawa. Various parameters of EMF exposure were measured: RMS values of electric and magnetic fields strength from various frequency ranges (static magnetic and from the range 5Hz-3GHz) and frequency spectrum of EMF. The results of measurements cover current values of electric and magnetic field strength and registration of time variability of exposure level (6-minutes and 8-hours shift registrations of dt=5 seconds). Results: The results of EMF investigations showed that in the majority of cases, the exposure levels were significantly lower than ICNIRP general public exposure limit (app. 1% of it or even lower). EMF's from welding devices can exceed even worker's exposure limit. But in all cases, a very significant short EMF's pulses/transients were found, especially in the case of low frequency magnetic fields. The maximum value registered within particular pulses are in many cases comparable with the general public ICNIRP's limit. A lot of places are exposed to static magnetic field and other components at once. High variability of exposure level were also found in many cases (within the range of 10–100 fold during a shift). Discussion and conclusions: The obtained results may be considered as typical for investigated kind of general public and occupational exposure conditions. It is still significant lack of epidemiological and biomedical studies taking into consideration above-mentioned complex parameters of EMF's exposure. Investigation concerning EMF from ELF and RF ranges is very important for epidemiological studies, especially when all components of exposure are weak, and should be taken into consideration. The “environmental” exposure pattern is so complicated that carrying out an experimental study of all possibilities of simultaneous exposure is absolutely impossible. The first step of such a study could be a good quality epidemiological study based on appropriate dosimetry, taking into consideration all exposure components.