What is Electromagnetic Radiation? When you sit in front of a computer or television, you are being bombarded by harmful waves quietly emanating from it. Even if you turn off the device, your biomagnetic field is still bombarded 24 hours a day, 7 days a week by the EM radiations from power cables, electric and electronic instruments. If you use a CRT based computer for many hours, some ill effects like eyestrain and fatigue may develop which is known as Computer Vision Syndrome.
Electromagnetic waves are emitted by many natural and man-made sources and play an important part in our lives. We are warmed by the electromagnetic emissions of the sun and we see using the part of the electromagnetic spectrum that our eyes detect as visible light. Electromagnetic (EM) radiation is a self-propagating wave in space or through transparent matter. EM radiation has an electric and magnetic field component which oscillate in phase perpendicular to each other and to the direction of energy propagation.
Electromagnetic radiation includes radio waves, microwaves, terahertz radiation, infrared radiation, visible light, ultraviolet radiation, x rays and gamma rays. The electromagnetic spectrum extends from below the frequencies of radio waves at the long-wavelength end through gamma radiation at the short wavelength end.
Human body is exposed to different kinds of EM radiation that includes the natural radioactivity in the earth, cosmic rays from outer space and also man made radiations coming from electric and electronic instruments. Diagnostic X ray machine, television sets, computers, microwave oven, radar devices, laser devices, mobile phones etc, generates radiations of different frequencies which exists in our environment as electronic smog.
Dangers of Household Radiation Part 1
Dangers of Household Radiation Part 2
When you sit in front of a computer or television, you are being bombarded by harmful waves quietly emanating from it. Even if you turn off the device, your biomagnetic field is still bombarded 24 hours a day, 7 days a week by the EM radiations from power cables, electric and electronic instruments. Extremely low frequencies waves (ELF) exist wherever electricity flows and radiate it from every electrical item in your environment. ELF radiation, the most underrated of the electromagnetic spectrum, deserves evaluation.
CRT (Cathode Ray Tube) based computer monitors use a beam of electrons accelerated by high voltage to generate image on the fluorescent screen. X rays may be produced when electrons are accelerated by high voltage, and strikes an obstacle in vacuum. In CRT based monitors, the image is formed by shooting a stream of electrons on the back of the screen, scanning back and forth across the screen, one line at a time. These electrons cause the screen to light up to produce the picture. Some of the energy from the electron beam escapes in the form of radiations at various frequencies particularly in the VLF (Very Low Frequency) and ELF (Extremely Low Frequency) bands.
The spot of electrons which sweeps the screen generates PEMR (Pulsed Electromagnetic Radiation) which at close range, disturbs the balance of all living cells. It has been established that, the harmful effects of PEMR exists all around the screen, especially in front and behind the monitor. The PEMR persists several hours even after the computer is switched off. Most people know that sitting too close to the screen increases the danger of radiation. But many do not realize that the sides and rear of the monitor are more dangerous. This means that even if you stay at two feet safe distance away from the screen, you may get radiation from the sides or rear of another computer terminal.
Computer Vision Syndrome (CVS)
If you use a CRT based computer for many hours, some ill effects like eyestrain and fatigue may develop which is known as Computer Vision Syndrome. This is mainly due to pulsed electromagnetic radiation and artificial light from the monitor. The same thing happens if you watch TV for long time. The CRT monitor uses fast beam of electrons that generates pulsed electromagnetic radiation carrying energy. At close range, this energy disturbs the metabolism and electrical activities of living cells.
Artificial fluorescent light from the monitor is the form of fractioned light which leaves out many segments of the spectral range. Flickering of the screen is also dangerous since the flickering rate is higher than the ‘Flicker-Fusion’ rate of the human eye. CVS is also caused due to bad contrast or excessively or poorly illuminated screen. Background illumination, posture, positioning of the monitor, ocular conditions like dry eyes and uncorrected refractive errors etc, increases the risk of CVS. Close watching reduces the muscle movements of the eyes and causes strain and fatigue.
To reduce the effects of CVS, many safety measures are recommended. The first and most important rule is to keep a safe distance of 14 inches from the screen although 24 inches preferred. More than 24 inches distance is necessary from the sides and rear of a near by monitor. It is important to note that Laptop computers using Liquid Crystal Display (LCD) are completely safe since there is no X ray emission from the screen.
Several problems have been observed in people who spend more than four hours a day in close proximity to an unprotected video terminal that uses a CRT based monitor. Stress, headaches, irritability, insomnia, eye strain, abnormal general fatigue, decrease in natural immunity, hormonal disturbances, disorders in the menstrual cycle are some of the ill effects of radiations.
Even more disturbing fact is that, exposure to radiation for long periods reduces spermatogenesis as observed in experimental animals. As the principle of precaution says “Faced with the risk of serious and irreversible damage, we cannot wait until we have all the scientific evidences before taking precautionary measures”. “Absence of certainty must not delay action”. Then what can we do? We can do something to protect ourselves.