What are Electric and Magnetic Fields? (EMF)

Electricity is an essential part of our lives.

Electricity powers all sorts of things around us, from computers to refrigerators Use of electric power is something we take for granted.

What are electric and magnetic fields?

Electric and magnetic fields (EMF) are invisible lines of force that surround any electrical device. Power lines, electrical wiring, and electrical equipment all produce EMF.

Some people wonder whether EMF might have some bad effects our health.

We are exposed to EMF almost everywhere we go, at home, at school, in stores, and even outside when we are near all types of electrical equipment, wiring, and power lines.

EMF decreases rapidly as you get farther away from the source.

Alternating current (AC) or direct current (DC)?

In the United States, if something is plugged into a household wall socket, it is using AC. AC reverses direction in the electrical wiring—or alternates—60 times per second, or at 60 hertz (Hz). If something uses batteries, the electric current flows in one direction only, and it is using DC.

What happens when I am exposed to EMF?

In most practical situations, DC electric power does not induce electric currents in humans. AC electric power produces electric and magnetic fields that create weak electric currents in humans.

Being exposed to some kinds of EMF may have some bad effects on humans, but scientists do not know for sure. Because of this, NIEHS recommends that people learn practical ways of reducing exposures to EMFs.