1. Before purchasing a building site, I’d like to make EMF measurements. Where can I request helpful information (in Belgium)?
You can contact ELIA, the electricity company, which can perform the necessary measurements free of charge (for high voltage lines under their management).
Within the BBEMG, you can also contact the ACE team or the Public health team. Travel expenses and measurements will be provided on request by the teams involved.
2. I live in Holland and my house is situated less than 40m from a 150 kV power line. Could you recommend a reliable person/institution that can measure the magnetic field inside my house?
In the Netherlands, we suggest you to contact het Rijksinstituut voor Volksgezondheid en Milieu (http://www.rivm.nl/Onderwerpen/H/Hoogspanningslijnen). You will find there expert contacts and advice for measurements.
Otherwise, you could also contact Dr Eric Van Rongen, a secretary of the Health Council of the Netherlands. He knows the subject very well and will be able to direct you to people who make measurement in your country. His email is E.van.Rongen@gr.nl.
3. We are about to buy a house along which a medium voltage powerline passes (20 000 V). In the other side of this estate, at 550 m, a high voltage powerline passes (70 000 V). Do you know who we can contact in France to take measurements of electromagnetic fields?
A priori, 20 kV lines do not create high fields and the distance from the 70 kV line assures you of a negligible influence. The french FAQ contains additional information.
4. I’m looking for an apparatus to measure the 50 Hz field at my workplace and home.
The measurement of low frequency (50 Hz) electric and magnetic fields requires specialized equipment, which must be regularly calibrated. Such equipments are very expensive, and we do not, as a general rule, advise the general public to acquire them.
Within the BBEMG, you can contact the ACE team or the Public health team to perform measurements.
5. What devices are used to measure 50Hz EMF?
Several devices are available to measure EMF. However, measurements have to be made with caution, particularly for electric fields, as they are influenced by the presence of the person performing the measurements. The best way to realise valid EF (electric field) measurements is to use an isolated pole, thereby keeping oneself or other objects aside. It is different for MF (magnetic field) measurements: at very low frequencies, these are not disturbed by the presence of persons or objects and they can be measured by a personal dosimeter carried at the belt to carry out measurements over a longer time period.
6. I’m looking for a commercial tool to measure electromagnetic waves. Are we forced to combine a teslameter with an electric field measurement?
The first thing is to specify frequency range. In low frequency (from 0 to a few KHz), we are in a so called “near field” (see question 1 in FAQ on calculations and technical questions): in this case, E (electric field expressed in V/m) and B (magnetic induction field expressed in Tesla or Gauss) have to be measured separately.
In high frequencies (like the radio, TV or mobile phones), E and B fields are linked together at around some ten centimeters from transmitters .
Apparatuses capable of evaluating fields in the whole range exist but they are very inaccurate. Some devices are available for the general public, and others, more expensive, are intended for professional use. You can easily find them through the internet. However, please be aware that accurate measurements of high frequency fields require a deep knowledge of electromagnetic phenomena. In any case, if you intend to purchase a measuring instrument, we also advise you to become aware of its sensitivity.
Within the BBEMG, you can also contact the ACE team or the Public health team.
7. I would like to measure the magnetic fields inside my house and in my garden. I’ve seen that there are mobile apps to do this, are they reliable?
According to our tests, most mobile applications measure the earth’s magnetic field and not the 50 Hz magnetic fields generated by the power grid and our electrical appliances. None of the applications our team tested in the laboratory were able to correctly measure 50Hz magnetic fields. This is because the magnetometer built into mobile phones is designed to measure the earth’s magnetic field in order to provide a compass functionality.
It should be noted that one of the applications tested seemed to be more sophisticated than the others. However, the results differed depending on the phones used for the tests: either the magnetometer built into the phone was not sensitive enough to detect very small variations (<1µT), or the results (from a another phone) were completely wrong.
In conclusion, to the best of our knowledge, there is no mobile phone/application combination that can reliably measure 50Hz magnetic fields.
