SECONDARY ISSUES TO THE USE LIFE-CYCLE STAGE OF COMPUTER DISPLAYS

Electric and magnetic fields (EMFs) are invisible lines of force that surround any electrical device, including power lines, electrical wiring, and electrical equipment. Electric fields are produced by voltage and increase in strength as the voltage increases. Magnetic fields result from the flow of current through wires and or electrical devices and increase in strength as the current increases. Most electrical equipment has to be turned on for a magnetic field to be produced, but electric fields are present even when equipment is switched off as long as it is connected to an electric power source. Electric fields are weakened or shielded by materials that conduct electricity (including human skin). Magnetic fields, on the other hand, pass through most materials and are therefore more difficult to shield and of greater concern. Both electric and magnetic fields decrease with distance from the source (NIOSH, et al 1996). Most information on EMFs from video display units (VDUs) pertains to CRT monitors. The following is excerpted from the World Health Organization fact sheet, “Video Display Units (VDUs) and Human Health (1998):” “The typical VDU creates images in a large evacuated cathode-ray-tube (CRT) by directing a beam of high-energy electrons from the cathode onto a special phosphor