Are Computers Hazardous to your Health?
Nov 21, 2001 11:45 AM
Electromagnetic Fields and Radiation
Q: Do computers emit electromagnetic fields and radiation?
A: Yes. The computer monitor (also called the video display terminal or VDT) contains a flyback transformer that controls electron beams to produce the image you see on your screen. The transformer produces "very low frequency" (VLF) electromagnetic radiation. In addition, computers emit "extremely low frequency" (ELF) electromagnetic fields. These ELF fields are produced by every appliance and piece of office equipment that runs on electrical current.
Q: Is exposure to electromagnetic fields and radiation a health hazard?
A: Scientists have long known that exposure to ionizing radiation (high frequency electromagnetic energy) like that associated with X-rays and gamma rays can cause cancer. However, there is an open question about the long-term effects of the lower frequency, less powerful non-ionizing radiation associated with computers and microwave ovens and the extremely low frequency electromagnetic fields associated with electrical current.
Previously, scientists thought these electromagnetic fields were harmless. But recent research has shown that some types of low frequency electromagnetic energy can harm laboratory animals. In addition, some epidemiological research (studies of groups of people to identify environmental, occupational and other factors that may be responsible for particular diseases) has suggested that workplace exposure to low frequency electromagnetic fields and radiation may be associated with miscarriages, birth defects and cancer. Other studies, however, have found no such link.
More epidemiological and laboratory research is now under way. It may take a decade or more, however, for scientists to determine whether computers and the electromagnetic energy they produce can be responsible for serious health problems. Meanwhile the manufacturers of computers and computer monitors have taken steps to significantly reduce electromagnetic emissions from newer equipment.
Q: If scientists don’t know if electromagnetic fields and non-ionizing radiation are hazardous, should we be concerned?
A: Many scientists and public health workers suggest that the prudent response to the current scientific uncertainty is to reduce exposure as much as possible in order to be on the safe side. Information on minimizing your own exposure is included here.
Q: Are there any government standards to protect workers against exposure to electromagnetic fields and non-ionizing radiation from computers?
A: The United States government has not set any limits on the amount of electromagnetic emissions from computers, but the Swedish government has set stringent limits on ELF and VLF emissions. Fortunately, the Board of Education has responded positively to pressure from the UFT and has agreed not to purchase any computer equipment that does not meet Swedish standards.
Q: Is there anything I can do myself to minimize exposure to electromagnetic emissions from our office computers?
A: The most effective thing you can do is work with your colleagues to arrange your office so no one is sitting or working closer than three feet from the back or sides of any computer. (Since the flyback transformer is housed in the back of the computer, this is where the VLF emissions are highest.) This strategy will protect you because the strength of electromagnetic emissions declines quickly as you move away from the source.
Although VLF emissions are lowest at the front of the monitor, you should sit 18 inches or more away from the screen when you are working at the computer. As already noted, this also is the best distance for your eyes.
Since walls do not block magnetic fields, be sure no one is sitting closer than three feet to the back or sides of a computer in an adjacent office.
Q: Do the electromagnetic radiation shields advertised by some manufactures work?
A: According to Mark Pinsky’s The EMF Book: What You Should Know About Electromagnetic Fields, Electromagnetic Radiation and Your Health, screens that fit on the front of the monitor are not effective in reducing electromagnetic emissions. However, a shield that takes the form of a metal band that clips to the computer and wraps around it works well. But you don’t really need one of these expensive shields if you can arrange your office so there is adequate distance between you and the back of any computer.
Q: What about time spent at the computer?
A: If feasible, reducing the number of hours you spend at the computer is an effective way to reduce exposure to electromagnetic energy. Some women who are pregnant or thinking about trying to conceive have made a special effort to arrange their jobs to minimize computer time.
Q: You said that extremely low frequency (ELF) electromagnetic fields are produced by all electrical equipment and appliances. What can I do to protect myself against exposure from these other sources?
A: Computer printers, copy machines and electric typewriters produce more substantial ELF emissions than computers do. Try to sit more than three feet away from such equipment and turn it off whenever possible.
At home you should be concerned about electric blankets, electric can openers and microwave ovens among other appliances. For information on reducing exposures to both ELF and VLF waves at home and in the office consult, Pinsky’s The EMF Book.
