Questions and Answers About EMF Electric and Magnetic Fields Associated with the Use of Electrical Power.
January 1995.

Electric Power Background

Q. What are EMFs?

A. Power lines, electrical wiring, and appliances all produce electric and magnetic fields. EMFs are invisible lines of force that surround any electrical device. Electrical and magnetic fields have different properties and possibly different ways of causing biological effects. Note that while electric fields are easily shielded or weakened by conducting objects (e.g., trees, buildings, and human skin), magnetic fields weaken with increasing distance from the source.

Even though electric and magnetic fields are present around appliances and power lines, more recent interest and research have focused on potential health effects of magnetic fields. This is because epidemiological studies have found associations between increased cancer risk and power-line configurations, as shown (97K gif), which are thought to be surrogates for magnetic fields. No such associations have been found with measured electric fields.

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