Assessment of ELF fields in urban environments in Spain
[See my comments following]
http://www.terra.es/personal/kirke1/noti67/epdf.htm
Exposure assessment of ELF magnetic fields in urban environments in Extremadura (Spain).
Paniagua JM, Jimenez A, Rufo M, Antolin A.
Departamento de Fisica, Escuela Politecnica, Universidad de Extremadura, Caceres, Spain.
email: paniagua@unex.es
We present the results of a study of the extremely low frequency (ELF) magnetic fields in urban environments of the Extremadura region (Spain). The study included a spectral analysis, an analysis of the temporal variation, and spot measurements in the streets of four cities. The spectral analysis showed that the main source of magnetic field exposure was that corresponding to the principal power frequency (50 Hz) and its third harmonic. The magnetic flux density measured at one point over 24 h presented rapid fluctuations in short time periods. Smoothing the time series eliminated these fluctuations, showing a temporal evolution associated with the differing levels of power consumption over the course of the day. The values of the spot measurements taken in the streets were all below the ICNIRP reference level, although 30% surpassed 0.2 microT, the value that some epidemiological studies take as the threshold above which there exist risks of effects that could be harmful to health. The values found for the magnetic flux density in these urban settings were generally greater than values reported in the literature for residential areas, and similar to, although in some cases less than those in workplace environments.
Copyright 2003 Wiley-Liss, Inc.
Source “Sylvie”
Don’s comments:
It would appear from the above that the measurements in this study were only taken in the streets and not in homes. I have emailed the authors for clarification. If it is only street measurements this study was a complete waste of time and effort, except possibly for homeless people who sleep on the streets!
Street measurements would be closer to the street power lines than the homes and so these measurements tell nothing about what may be happening in the homes. It is where people spend many hours per day/night that needs evaluation, such as sleeping areas and office work areas for example. In Australia many homes are built so that the meter box is on a bedroom wall, giving rise to a situation where bedheads may be placed next to the meter box and thus exposure to electric and magnetic fields whilst sleeping is the prime source of exposure.
The Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) is in the early stages of a residential EMF survey in Melbourne (300 homes) and it will concentrate on exposures within the homes – a far more relevant parameter than what is happening on the footpath! And if they include bed head measurements it will be exactly what is needed.
Don
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