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Electromagnetic Fields (EMFs)en español

What are electromagnetic fields?

Electric and magnetic fields, commonly called electromagnetic fields (EMFs), are invisible lines of force that result from the motion of an electric charge. They can be produced by natural and human sources. Natural sources of EMFs include natural light, ultraviolet light, and thunderstorms. When produced by human sources, electric fields are produced by voltage; magnetic fields are produced by the flow of current through wires or electrical devices. Electric power lines, electrical wiring, and electronic equipment all produce EMFs in varying frequencies. Other sources of EMFs include X-rays, radios, microwave ovens, cellular telephones, and computers. There is no evidence that short-term exposure to EMFs at the low levels present in the environment or at home is harmful to human health, according to the World Health Organization. Exposures to higher levels of EMFs that might be harmful are restricted by national and international guidelines.

This description is based on the information found in the Web links listed with this topic.


Web Links from MedlinePlus (National Library of Medicine)
Electromagnetic Fields
Radiation Exposure

More Links
Are Electromagnetic Fields Hazardous to Your Health? (Ohio State University Extension) (PDF — 218.35 KB)
Cellular Phone Towers (American Cancer Society)
Electric and Magnetic Fields (National Institute of Environmental Health Sciences)
Electromagnetic Fields and Public Health: Intermediate Frequencies (World Health Organization)
EMF (Electric and Magnetic Fields) (National Institute for Occupational Safety and Health)
EMF Radiation from Power Lines. RadTown USA (Environmental Protection Agency)
Extremely Low Frequency (ELF) Fields (Occupational Safety and Health Administration)
Radiofrequency and Microwave Radiation (Occupational Safety and Health Administration)


Last Updated: November 25, 2013

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