The Physics
Factbook
An encyclopedia of scientific essays

Magnetic Field in a Typical US Home

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Bibliographic Entry Result
(w/surrounding text)
Standardized
Result
Magnetic Field Strengths. Orange County Hyperbaric & Laser Medicine.
TeslaGaussMarker
10−410near household wiring
100 µT
Short Fact Sheet on EMF. California Electric and Magnetic Fields Program.
homes below average
field strength
736 homes
measured
10%0.43 mG
25%0.54 mG
50%0.71 mG
75%0.98 mG
90%1.58 mG
0.043โ€“0.158 µT
National Institute of Environmental Health Sciences. How High are Exposures in the US Population? NIEHS Report on Health Effects from Exposure to Power-Line Frequency Electric and Magnetic Fields. "Average 24 hour magnetic field exposure for individuals in the US population is about 0.09 µT." 0.09 µT
National Institute of Environmental Health Sciences. Your EMF Environment. Questions and Answers about EMF Electric and Magnetic Fields Associated with the Use of Electric Power. [several tables]
bathroom, kitchen, living room, laundry room, bedroom, electric blanket, workshop, office
0.1โ€“150 µT
Alberto Lozano-Nieto. "Electromagnetic Fields in your Home." Popular Electronics. January 1999. "The background level of magnetic field strength (all appliances turned off) measured in the basement at the operator's chest level was found to be 2 mG, while at the head level it was 3 mG." 0.2โ€“0.3 µT

There is a secret force working covertly to affect you. You can't smell it, see it, hear it, or touch it. You probably don't even know it exist but you are in affect of it everyday at your home. You are getting very scared now but you really don't have to. It is too weak to do much harm. I am talking about the magnetic field.

The magnetic field? It doesn't affect me I don't have any magnets in my house! Wrong. Magnetism also results from moving charges, and moving charges are called currents. This means that there is a magnetic field present near every electrical wire or appliance in your house. In fact, right now as you are reading this, you are sitting right in the magnetic field from your computer monitor. But as I mentioned, those magnetic fields are very weak. The SI unit for magnetic fields is the tesla, T. As you can see, all the values above are in micro teslas, µT, which is 10−6 T. The biggest value of 150 µT, still very small, is the value only if you were to sit right next to a wire all day, which is unrealistic.

However, governments in the US, Sweden, and Denmark had still done research on the effects of magnetic fields to people at their homes. Many oncologists think that magnetic fields are responsible for causing a typical childhood cancer, acute lymphoblastic leukemia (ALL). The investigations by these government agencies had however proofed otherwise. Their evidence points out that there's only a very tiny elevation of chances of ALL in children living right next to a high-tension power transmission line. The small, elevated percentage was deemed to be inconclusive by the researchers.

Ming Lui -- 2001