I received the following message fromKatharina Gustavs with the request to post on my list as a “right-of-reply” to certain comments made by Magda Havas in message # 359.
( https://www.emfacts.com/weblog/?p=359 )
I have the greatest of respect for both parties but request that any further correspondence should be done directly with each other on this matter.
Dear Dr. Magda Havas,
First of all, many thanks for your clear words on the application characteristics of the Stetzer Filters in your recent posting on the EMFacts blog (8 January 2006). It is good to hear about your studies, in which the Stetzer filters could be installed with good results. I read your studies with great interest. As you said yourself, it would be great to have data on ground currents as well. In addition, I would be interested to know if you took AC magnetic and electric field measurements in free space for the ELF and VLF range at the Willow Wood School in Toronto.
Secondly, I do not know why you did not contact me directly if you really were interested to learn in which of my consulting projects Stetzer filters did not seem to provide the most optimal solution for my client. In one particular case, when I was first introduced to the Stetzer filters, the wiring system of the house not only suffered from major ground current issues, but also involved an inverter for an alternative energy system. In addition, the whole place was exposed to a high external RF radiation source. In contrast to the Stetzer filters, which only absorb harmonics between 4 and 100 kHz, a shielding solution protecting from electric fields (ELF+VLF) as well as RF radiation at the same time produced measurable elimination of the electric field exposures in the sleeping area.
Thirdly, you obviously accuse me of “deliberately trying to provide misleading information.” I, hereby, dismiss your unsubstantiated accusation.
Fourthly, as a building biology consultant and current translator/researcher for the original building biology correspondence course (www.buildingbiology.net/inonstprcopa.html) I would like to take the opportunity to share some information about the building biology approach to testing. The Building Biology Guidelines (English translation on the internet located at www.milieuziektes.nl/Rapporten/SBM%202003%20US%20TH.doc or go to http://www.milieuziektes.nl/Pagina100.html, click on SBM 2003 in the top row, scroll down and click on English version of SBM 2003) are specifically designed for sleeping areas because humans seem to be most vulnerable to electromagnetic interference during sleep. Therefore they are the lowest exposure guidelines worldwide. As far as electromagnetic pollution is concerned, the Building Biology Guidelines cover the entire electromagnetic spectrum. With regards to the non-ionizing radiation portion, building biology differentiates between five major frequency bands (AC magnetic fields, AC electric fields, RF radiation, DC magnetic fields, DC electric fields). The guidelines list the recommendations for AC electric and magnetic fields in the ELF range because those frequencies are often most dominant and reach much further into space. Frequencies in the VLF range are considered more biologically active, which is why in building biology only a 10th of the ELF exposure limits are recommended for the VLF range. All of those fields are measured in free space with calibrated testing equipment, exactly where a person sleeps or works most of her or his time.
Compared to magnetic field research, there have been rather few studies on 60-Hz electric-field effects. When Wolfgang Maes, the co-founder of the Building Biology Guidelines, had 500 of his EMR surveys from the 1980s analyzed for the dominant ELF factor in the bed where people actually sleep, it was not the magnetic field component, but the 50-Hz electric field component that seemed to contribute the most to electromagnetic exposure in bed. (The electric field measurements were taken with state-of-the art equipment from www.combinova.se, one of the research companies involved in the development of the Swedish low-emission standard for computer monitors www.tcodevelopment.com).
In 1997 Gisbert Gralla, Ph.D., an electrical engineer from Germany, came to the same conclusion when he compared AC electric and magnetic field measurements for over 300 EMR surveys of sleeping areas. He measured the actually induced body current on the skin of sleeping subjects caused by the 50-Hz electric field component. The induced body current caused by the magnetic field component was calculated from the ambient magnetic field measurements. (www.datadiwan.de/netzwerk/index.htm?/esmog/es_98_02.htm The summary in the Elektrosmog Report published by the Nova Institut is in German only.) The specifics of the measurements are documented in the Journal of Electro- and Magnetobiology, which is now called Electromagnetic Biology and Medicine: Gralla, G: Estimation of 50-Hz electrically vs. magnetically generated body currents in sleeping subjects. Electro- and Magnetobiology 16(3), 235-241 (1997).
Roger Coghill, the pioneering EMF researcher from the UK, also moved his testing equipment right into the beds where children sleep and took 50-Hz electric field measurements. In his 1996 pilot study (reported on in his presentation at the Childhood Leukemia Conference 2004 www.leukaemiaconference.org/programme/posters/day3-coghill2.pdf) he found a “near five fold relative risk [of childhood leukemia] using a cut off of 20 V/m.” (From plugged-in extension cords running along a bedside, my electric field meter often registers above 20 V/m at 60-Hz even at three feet away right in the bed, but at a three-feet distance I usually do not measure VLF signals anymore except for there are fluorescent lamps including energy-saving lamps or an inverter for an alternative energy system turned on, to name only two of the more prominent sources of major VLF exposure in residences.)
There is no doubt that transients and harmonics that reach the human body are biologically active and it is therefore desirable to eliminate or drastically reduce human exposure to them. I am very well aware of the fact that Stetzer filters absorb harmonics between 4 and 100 kHz on the electric circuits they are plugged into. It should be noted here, however, that a lot of modern electronic equipment generates harmonics at much higher frequencies, which is why the above-mentioned TCO standard (www.tcodevelopment.com) requires VLF electric field testing between 2 and 400 kHz. According to the TCO testing standard, the VLF signals are measured in free space 30 cm away from the monitor where the potential computer user will place his or her body.
In building biology we acknowledge the fact that the human body makes use of almost all frequency bands of the entire electromagnetic spectrum (e.g. cell membrane potentials with static electric fields, brain waves and heart pulses in the ELF range, enzyme activity at radiowave frequencies, body heat in the infrared range, visible light for melatonin synthesis, UV-B for Vitamin D synthesis, etc.). Therefore building biology does not only focus on one single frequency band, but tries to assist people to restore their electromagnetic sleeping, living and work environment back to the natural settings throughout the entire electromagnetic spectrum including 60-Hz electric fields. In building biology we always analyze ground currents and determine the dominant frequency of the electrical power at the actual cables. The building biology exposure guidelines, however, are first concerned with the measurable actual exposure of the human body to the various frequencies of the AC magnetic and electric fields.
Building Biology Consultant