Rhythmic force fields
Article from TÜV SÜD Journal 4/2010
 | Cell phones, medical equipment and automotive safety systems: electronic devices make our lives easier and safer. But the invisible waves emitted by radios and flat-screen televisions unsettle many people. Using cutting-edge technology, TÜV SÜD determines whether thresholds are maintained – and ensures that devices do not interfere with one another. |
You cannot see, hear, smell or taste it. Perhaps, this is why there is something mystical, almost eerie about it. Electromagnetic radiation is everywhere in our modern world. The word alone! »Radiation« – that sounds at first like radioactive, or harmful at any rate. But who wants to give up cell phones, unplug the refrigerator or do without the many electrical helpers used everyday? Force fields arise wherever such devices are used. Electromagnetic fields are a combination of electrical and magnetic energies that can change their strength and direction in a certain temporal rhythm and, as a result, have various frequencies. Cell phones, for instance, operate at high frequencies, computer terminals at middle frequencies and power lines at low frequencies.
Hearts embedded in electromagnetic fields
Electromagnetic radiation is not artificially created. Humans themselves are electromagnetic: »Even when there are no outer electrical fields, small electrical currents are flowing in the human body,« the World Health Organization says. »Nerves, for example, generate their signals in the form of electrical impulses. Most biochemical reactions, from digestion to brain activity, are accompanied by the rearrangement of charged particles.« And anyone who has had an EKG, or an electrocardiogram, knows that the human engine, the heart, is embedded in an electromagnetic field.
What makes some people worry that too much radiation will harm their health? »We live in an electronic world. The number of new devices is rising, even if old ones are disappearing: Of course, the use of electromagnetic fields is rising with it and exposure as well,« says Rüdiger Matthes, Head of the Working Group Non-Ionizing Radiation at the German Office for Radiation Protection. Take mobile telephones: »Both the use of cell phones and cordless fixed-line phones has significantly grown among the population since the last survey was conducted in 2006 and now totals 88 percent and 91 percent, respectively,« the agency writes in its final report in 2007 on »Determination of Worries and Fears Among Large Segments of the Population Concerning the Potential Dangers of High-Frequency Electromagnetic Fields of Mobile Telephony.«
A good portion of realism
The study also made this finding: Among the 2,500 respondents, electromagnetic radiation ranks rather low among a number of potential health risk factors. People are concerned in particular about transmission masts. »But eating meat of an unknown origin is considered much more of a danger among citizens, followed by genetically modified foods, air pollution, the side effects of medications, UV radiation, heavy smoking and excessive consumption of alcohol,« the BfS writes. Of a potpourri of threats, the most ominous appear to be those that a person can directly experience in his or her own body. Nonetheless, researchers are devoting a large share of their time to studies that explore the issue of mobile telephony and its dangers – ranging from the »Research Report: Children's Health and Mobile Telephony« by the Jülich Research Center and »Brain Tumors in Northern European Countries and Mobile Telephony« by the Danish Cancer Society to an »Examination of Sleep Quality Among Electrosensitive Residents of Base Stations under Domestic Conditions« by the Technical University of Graz. The unanimous conclusion: no evidence of any harmful effect from electromagnetic fields. The Interphone Study that was coordinated by the WHO and released at the end of May found no link between the use of cell phones and the risk of getting a brain tumor. According to the International Agency for Research on Cancer at the WHO, the widely cited study confirmed the results provided by a variety of previous studies.
Just a lot of hot air then? Not exactly. The WHO estimates that 25,000 articles about the biological effects and medical applications of non ionizing radiation have been released over the past 30 years. »Even though some people feel that more research must be done, the scientif-ic findings in this area are more comprehensive than they are about most chemicals,« the WHO says. Nonetheless, the Geneva-based agency adds, some information about the biological effects is still lacking, which makes addi-tional research necessary.
Strict thresholds apply. In Germany, they are laid down by the 26th German Emission Protection Ordinance. Under this law, thresholds for low frequency electrical and magnetic fields are set at 50 Hz (household electricity) and at 16 2/3 Hz (electrified transport systems) as well as high frequency electromagnetic fields starting at 10 MHz. These levels are selected in such a way that, on the basis of today's available knowledge, »the health risks from electromagnetic fields found by scientific research will not occur even after long-term exposure,« according to the German Office for Radiation Protection.
This applies not only to that sensitive being, the human, but also to electronic products that must also be protected from electromagnetic radiation and, thus, from themselves. After all, electromagnetic interference is pro-duced by nearly every electronic device. For this reason, the EU has issued Directive 2004/108/EG as well as the corres-ponding CE-marking requirement for all manufacturers of such products. This means one thing: Each product may cause only a limited amount electromagnetic interference to ensure the operating ability of other devices, and the product itself should not be subject to disruptions.
Making sure that pacemakers keep up the pace
Stefan Kammerl, Head of Sales and Marketing at TÜV SÜD Senton sums it up this way: interference transmission and interference immunity. »Here's an example: When you drive under a radio tower, the airbag should not suddenly inflate – such a disruption would be life-threatening.« The pacing provided by a pacemaker should not be upset when a refrigerator comes on. Admittedly, the examples are slightly exaggerated. TÜV SÜD Senton tests the electromagnetic compatibility to ensure that such events do not occur.