The computer as a source of an electric field

Computer radiation spectrum consists of X-rays, ultra-violet and infra-red fields of spectrum, and also wide range of electromagnetic waves other frequencies. Spetialists consider that X-rays danger now is quite small. This kind of rays are consumed with the screen glass. But we have to remember that even very small intensity of X-rays promotes air ionization.

The personal computer as a source of an electromagnetic field

As regards the influence of electromagnetic lower frequency (50-100 Hz) radiation on a human organism, that is formed with computers and other domestic electric appliances, here scientists and consumer rights defenders haven’t arrived at a common idea. The last years checked investigations in this area, only increased alarm and put new questions, that don’t have answers.

Conducted experiments by physicians prove that radiation of videodisplay terminals may have stimulative influence on evolution of breast new growth. In medical literature there is an information about heightened oncological disease level of professional PC users. But until now nobody hasn’t studied electromagnetic fields influence on cancerous growth formation. Truth, EU has published ISO 9241 instruction, that calls to maximum electromagnetic radiation level lowering, and instruction, which tells that working with monitor operator has to be informated about precautionary measures.

When monitor is working on the screen of kinescope the electrostatic charge which create an electric field (EF). In different researches, under different conditions of measurement of value EF changed from 8 up to 75 kV/m. That is why people working with the screen monitor, gain an electrostatic potential. The dispersion of electrostatic potentials of the users changes in a range from -3 up to +5 kV/m. When EF is felt subjectively, the potential of the user is a determinative in occurrence of unpleasant subjective sensations.

The noticeable contribution to a common electric field is imported by surfaces of the keyboard and mouse, electrified from friction. The experiments show, what even after operation with the keyboard, the electric field fast increases from 2 up to 12 kV/m. On separate workstations in the area of arms registered strength of static electric fields more than 20 kV/m.

CRT terminals radiate electromagnetic waves in a very broad band. In a radio-frequency range they are produced by a cathode handset; the main source - horizontal and vertical deflection coils, which provide scanning an electron beam on the screen in a range 15 — 35 kHz. In distance 50 sm. from the screen the tension of an electric field changed from part of unity up to 10 V/m, and magnetic induction — from 10-8 up to 10-7 Tl. The CRT- terminals radiate also variable electrical and magnetic field with frequency 50 or 60 Hz and their harmonics.

The researches of a functional state of the user of the computer conducted by Centre of electromagnetic safety, have shown, that even at short-period operation (45 minutes) in an organism of the user occur considerable changes of a hormonal state and specific changes of biological currents of a brain under influence of electromagnetic radiation of the screen monitor . Especially brightly and steadily these effects appear for the women. Is remarked, that for groups of the persons (in this case it is 20 %) negative response of a functional state of an organism does not appear by which PC less than 1 hour. Outcoming from the analysis of the obtained results the is done the conclusion about possibility of creation special criteria of professional takeoff for staff which use the computer during work.

In the opinion of some investigator the electric field of CRT terminal with strength of 15 kV/m at an one-hour exposure of the teenagers, playing on the computer, strengthens excitative processes in a CNS and shifts a vegetative homeostasis.

The Swedish institute of protection from radiation in the report gives observed data of an electromagnetic field for 150 models of monitors

Maximum and averages value of electromagnetic radiation for CRT terminals according to the data of the Swedish institute of protection from radiation

In a number of investigations was found that electromagnetic fields with frequency of 50 Hz may initialize biological shifts (even the DNA synthesis violation) in animal cell. Especially amazed the fact of unusual property of electromagnetic waves: their influence danger don’t decrease with the radiation intensity lowering at all, and some electromagnetis fields act on cells only with the small radiation intensity or at definited frequencies.

For reduction of potential dangerous videoterminals’ radiation it is expediently to follow the special measures of protection from low frequency fields. Since display high voltage source line transformer allocated at the back or side part of a terminal, radiation level on a display back side panel is higher, at that, case sides don’t defend against radiation. Therefore users have to be situated farther than 1.2 meter's from the back or side surfaces of neighbor terminals.

In many cases in rooms, where computer technics are situated, work employees, which have no relation to it. However radiation negative influence spreads on them to, if their work places are wrong chosen. Operators, which rest near the working computers, are behaving unwise at all.

Last years observations and investigations found expedient of cactus pots placing near the computer displays. Their presence decrease harmful influence intensity of display electromagnetic radiation.