Today we have reached the point where we have computers small enough to be carried around and used on one's lap while travelling. They are many times more powerful than those which only two or three decades ago needed an entire air-conditioned room to house them. The use of computers at work and in the home has grown explosively. The extent of that growth would have seemed fanciful if predicted — even in 1970, when the electronic typewriter was just becoming standard equipment. Today, most small businesses and every large one would grind to a halt without the aid of these ubiquitous machines.

        One consequence of such a short history and rapid change is that, although it is beyond question that computers produce a variety of strong electrical and magnetic fields, there is still much room for debate as to the precise effects on health of all the various emissions. On top of that, the speed of changes taking place in equipment specifications means that conclusions of epidemiological studies are likely to  be out of date almost before the ink is dry on the paper.

        Certain facts are undeniable. For instance, it is still the visual display unit (VDU) which produces most of the disturbing fields that radiate from a conventional office computer or work station with a conventional cathode ray tube monitor (a TV-like screen). Even that must be qualified because over the last few years there have been tremendous changes in monitors. In the late 1980s low-emission types were still a comparative rarity in the UK. Those available were made mainly by Scandinavian companies. The Swedes led the way in imposing very strict limits on the legally permissible levels of electrical, magnetic and static fields that monitors could produce. If you wanted a low radiation monitor in 1980 it took quite some finding, and you would certainly expect to pay a premium price.

        The Swedish regulations were introduced following a number of studies of animals exposed to radiation from computers. For instance, in one set of experiments mice thus exposed had five times as many malformed offspring as those in control groups. As so often has been  the case, the studies were generally dismissed for one reason or another, although they were duplicated later. However a subsequent survey (see also " Research" be(ow) of a group of 1500 pregnant women in California showed that those using computers for more than twenty hours a week miscarried twice as frequently as did women in similar but non computer-based work. While the total number of birth defects was small enough to allow the statistical validity of the analysis to be questioned, the risk did seem to be of too high a significance to be ignored altogether.

        Today low-emission monitors are tending to become standard equipment on all but the very cheapest makes of computer. That said, there is still no agreed international standard on what constitutes a 'safe' level of the various electromagnetic fields produced by VDUs; indeed there is still what looks like official indifference. For example, the recent EU (European Union) directive on use of computers in the workplace concentrates entirely on ergonomics and the effects of possible eyestrain and makes no mention at all of EMFs. It is therefore still worth looking at the hazards that have been ascribed to computers.

        A normal screen produces high levels of both electrical and magnetic radiations at many frequencies (fig.6). First there are extremely low frequency (ELF) fields from around 15 to 50Hz. These are produced by the mains transformer and associated circuitry that controls the screen display, and are very powerfully 'spiked', which is to say there are very sharp peaks of power. There is also a wide range of radio-frequency fields and there are strong electrostatic fields, as high as!2to201<V. The potential hazards of all of these are on p.6. While these fields account for the bulk of the emissions from monitors, there is usually some microwave radiation. Most screens also emit some 'soft' X-rays and a small amount of gamma-radiation. However it has to be said that modern tubes produce what are probably negligible levels of these last three types of radiation.

        One very important consideration is that much electromagnetic radiation emanates from the sides and rear of a VDU, so it is not only the operator who is at risk. In fact field levels can be much higher behind the computer than in front. This is important to remember when planning the layout of an office, and when considering protection.

It is perhaps not surprising that a whole host of minor and major health problems have been ascribed to spending long hours in front of VDUs. The first questions were raised in the 1970s and '80s when Zaret's research suggested a causal link between working on VDUs and the incidence of eye tumours and cataracts,1 Then, over the period from 1979 to 1982 a number of studies in Canada and the U.S.A. seemed to show that pregnant women working on computer terminals suffered an alarmingly high incidence of miscarriages and congenital deformities (Table 5). These conclusions were based on the health histories of relatively small groups of workers, and so have been criticised as alarmist, but they led in Toronto at least, to strict laws banning pregnant women from such work and severely restricting the number of hours per day which anyone could spend at a VDU. Not long afterwards the Swedish authorities also concluded that there was cause for concern and (as mentioned earlier) they introduced stringent legal limits on the levels of electrical, magnetic and static fields that any VDU manufactured or used in the country could emit.

Emissions from Computers

It has to be said that the quality of VDUs has improved enormously since the date of these studies and electromagnetic emissions are far lower today. However, we still do not know what level, if any, may be considered safe. Whatever the truth eventually turns out to be, it does seem prudent for pregnant women to think carefully about whether any risk, even if not conclusively proven, is worth taking at such an important time of life. Since most thinking mothers-to-be are (understandably) almost obsessively careful about diet, use of drugs, exertion and general life-style factors.it would seem reasonable to suggest caution about possible electromagnetic hazards such as this.

Abnormality                                           Nos. Deformities                                             10 Miscarriages                                           38 Premature births                                      3 Respiratory Illness                                  2  Stillbirths                                                     1 Total abnormalities As % of total pregnancies                   62.8

 
Table 5: Abnormalities in 86 pregnancies of women working on VDUs (Canada &. USA 1979-82)

A major difficulty in researching this area has been that the introduction of computers tends to lead to many changes in working practices. It is not always clear whether it is these or the electromagnetic emissions that are to blame for some of the undoubted health problems suffered by many workers in modern offices. For instance, computer-based work is often very intensive, so that long hours can be spent without much movement away from the keyboard. Problems due to poor ergonomic design of chairs, desks and keyboards are thus highlighted. Modern keyboards needing only a very light touch make high typing speeds possible. With 'word wrap' on word processors (the machine automatically moving on to the next line when the current one is filled), there is not even the pause in rhythm and variation of movement that a mechanical typewriter required to push the carriage back to the start. Again, a complete document of several pages will often be prepared on screen before there is a break while a copy is printed.

A plausible case can thus be made that mental stresses, or neck, back and shoulder pains, or repetitive strain injury (RSI} an increasingly common affliction of the wrists and hands, or even some eye problems, may simply be due to considerations of a mechanical nature, or of working practices.
However, it seems unlikely that this is the whole story. Even the best designed office equipment does not appear to resolve the aches and pains associated with keyboard work. Nor are there records of typing pool workers showing signs of RSi when in the recent past they used electronic typewriters. These offered very similar 'touch' and potential for speed — and similarly intense workload.

        Those who worked in the highly electromagnetic environment of the London stockbrokers' dealing rooms of the City of London, surrounded by banks of VDUs, were reputedly the first to develop M.E. (whence the derogatory name of 'yuppie flu'). The high stress levels in that environment are well documented. Many VDU operators complain of sore, dry eyes. There appears to be more to this than the simple glare from the screen, as anti-glare filters can improve the situation, but fail to cure the problem. It seems more likely that the cause is static electrical charges building up on the skin and eyes, transferred from the field surrounding the screen and resulting in charged dust particles adhering to the eyeballs. Certainly, installation of an earthed conductive screen produces noticeably better results than a simple nylon mesh.

        There have also been reports of an abnormally high incidence of cataracts developing at around the age of thirty, not just in young women working with VDUs, but also in young male radar operators who use similar screens. The possibility of the electromagnetic emissions being to blame for this is supported by recent experiments which have shown that the radiations from a VDU will cause minute holes to develop in soft contact lenses, whether they are in the eye or not.

        Mention has been made of the growing use of portable machines, both the so-called lap-top (which can still be fairly bulky) and also the smaller notebook devices. All of these use alternatives to cathode ray tubes (CRT) screens. There are various types of liquid crystal display (LCD) units which use a principle similar to the pocket calculator, but are much more sophisticated and can be monochrome or colour. The thin film transistor (TFT) gives a display quality equivalent to a good CRT, but these are even more expensive than the LCD models. While it would be a brave person who would claim any of these to be hazard free, they do produce less radiation and certainly not the powerful spiked fields from the transformers in the CRT monitors.

        However, even the cheapest are significantly more expensive, so most offices continue to use conventional monitors and doubtless will do so for some time to come. It is also important to mention the obvious hazard of the lap-top model: if you do use one in your lap you will be likely to come into much closer contact with its electric fields than you would with a desk-top computer.
Of the remainder of the computer, the only part likely to emit noticeable fields is the hard disk drive which usually runs continuously while the computer is switched on and which will be part of almost all desk-top and portable machines. The electric motor that drives it will certainly produce measurable fields, but these are of a much lower  Intensity than from CRT monitors and will fall off rapidly even a foot or two away.  They do not seem to have been the subject of any published studies.
 

There are on the market, one or two partially effective filters that can be mounted in front of a VDU to reduce some field levels to more acceptable values, cutting down glare at the same time. There are many cases recorded of good response to such protection, particularly in reduced operator stress and fatigue, as well as the virtual elimination of sore eyes.

        However, you will recall how difficult it is to shield against magnetic fields and so no filter is going to offer much realistic protection against these. The electrical field component and the static field will be very greatly reduced and this is what must account for improved operator comfort. Whether any pregnant woman should consider that such a screen would offer adequate protection is a matter for individual decision. The question has to be whether any avoidable risk, however slight, is worth taking at such an important time of life.

        Short of scrapping existing equipment and installing new low radiation monitors, screen filters appear to offer the best solution currently available, it must be stressed that simple nylon mesh screens will not offer significant protection. Many other types promising great improvements fail to live up to the claims made for them. While a suitable filter will give a measure of benefit to the operator, we should not forget the way that radiation is emitted in all directions. Computers should be located so that other people using the room will be at least 3-4ft. (1-1.25m) away from any part of the unit. It is also prudent to look at screening for the back of the unit, reducing the powerful spiked ELF fields. Again, there are one or two products on the market which seem helpful in this connection.

        However good our precautions, until we know more about the risks, it is prudent to limit the number of hours per day an operator spends at a VDU. The latest EU legislation sets an upper limit of five hours daily at a stretch. It demands regular eye tests, although the concern is with the effects of optical glare and prolonged staring at the screen, rather than with electro-stress.

        One final piece of advice is simple, but can make a lot of difference: it is to move the keyboard two or three feet from the screen. It is also sensible to avoid computers with keyboards attached to the monitor (though these are not so common nowadays). This one precaution can reduce the field levels for the operator by 30% or more.

        While you will have gathered there are no entirely 'safe' distances, many researchers agree that sitting a minimum of three feet (1 metre) from the screen provides reasonable conditions for all but the most sensitive individuals. The typical magnetic field strength at this distance will be around ImG and, together with the use of an effective screen filter of the type described (which tackles electrical and static fields), the operator will be reasonably well protected.

        You may wish to refer to the list of suppliers at the end of this book if you want to know more about the availability of the products mentioned above.

NOTE
I.     Zaret, M., Cataracts and Visual Display Units — Health Hazards of VDTs, Pearce, R.G.(ed): Wiley, (1984).
Click on Following Chapters to Read or Download:-

Electrostress-
Chapter 01 Disease
Chapter 02 Vibrations
Chapter 03 Facts and Figures
Chapter 04 Bedtime Story
Chapter 05 Around the House
Chapter 06  Power Lines

Chapter 07 Computers
Chapter 08 Microwaves
Chapter 09 Some Solutions
Chapter 10 The Positive Side?

Geopathic (Earth Energies) Stress
11  Earth Stress, Earthquakes, Earth Sensitives
12 History of Ley Lines, Ionization Under Cancer Beds, Scientific Measurements
13 How to Use Divining Rods, Protect Yourself, Allergies
14 Unhealthy Earth Energies, The Hartmann Net and Curry Grid
15 Black Spirals, Crop Circles, Demons, Oscilloscope Measurement
16 Crossing Leys, Ion Effect, Allergic to Microwave Ovens, Graveyards, Quarries
17 Natural and Man-made Sources of Unhealthy Energies
18 Imprinting Your Own Energy
19 Eliminating Unhealthy Earth Energy
20 Cup-marked Stones or Petroglyphs
21 Human disease and Mother Earth

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