Electromagnetic Fields
Electromagnetic fields (EMFs) are natural phenomena consisting of two invisible forces - electric fields and magnetic fields - that surround any wire conducting electricity. Electric fields are created by the presence of an electrical charge in a conductor. Magnetic fields are created by electrical current -the flow of electrons through a conductor. In simpler terms, electrical fields exist around energized wire, even when an appliance is turned off. Magnetic fields exist only when the appliance is turned on and current is flowing. Either field by itself is harmless. When current flows through a wire both an electrical and a magnetic field is created - this combination is an electromagnetic field.
Electricity is used to provide lighting, run computers and televisions, and operate many different types of common household devices and appliances. Whenever there is a flow of electric current, both electric and magnetic fields also exist.
Electric fields are created by the presence of an electrical charge. Electric fields exist around any energized component, even when an electric device or appliance is turned off. The higher the voltage, the stronger the electric field. Magnetic fields exist only when a device or appliance is turned on and current is flowing. The greater the amount of current, the stronger the magnetic field.
When current flows both an electrical and a magnetic field – an electromagnetic field (EMF) is created. The unit of measure used to indicate the strength of EMFs is a milligauss. The device used to measure EMFs is a gauss meter.
EMFs are strongest when close to a source. As the distance from the source decreases, the strength of the fields also decreases. As an example, when an EMF measurement is taken six inches from a microwave or power saw, the level may be 300 milligausses. A foot away the level may drop dramatically to only 20 to 30 milligausses. Indoors, the EMFs from high-voltage power lines are actually relatively weak when compared to the fields close to household appliances. A high-power transmission line may produce an EMF level of 150 milligausses in the right of way below it but only 15-20 when 100 feet away.
The question of whether electromagnetic fields may be a factor in human illness has been the subject of scientific research in many parts of the world for several decades, especially as to if and how EMF exposure may contribute to childhood cancer. Scientific evidence to date, however, has not established a strong link; although the issue is certainly not closed.
It is clear that a high EMF level can induce weak electric currents to flow through the human body, resulting in immediate results. For example, peripheral nerve and muscle stimulation can be caused by intense magnetic fields, and minor shocks can be caused by an errant electric charge induced by high intensity electric fields. But in most cases, human exposure is typically limited to relatively low EMF levels.
In the United States and Canada, the electricity that powers electric devices and appliances flows back and forth at a relatively low frequency of 60 cycles per second. EMFs produced by this transmission and use of electricity are classified in the Extremely Low Frequency (ELF) category. These low-frequency EMF levels are even smaller than those produced naturally by the human brain, nerves or heart, and most studies indicate they are not associated with any known health risks.
The International Agency for Research on Cancer has listed ELF electromagnetic fields as “possibly carcinogenic” to humans based on studies of childhood cancer. However, this research group has also indicated that the evidence is not strong enough to conclude that EMFs definitely cause cancer.
According to the British Columbia Centre for Disease Control, the available scientific evidence to date,
“does not support the assumption that adverse health effects from exposure to these fields (ELF-EMF) at levels normally encountered in our homes, schools or offices pose a risk to human health.”Similarly, as a result of the findings of a comprehensive investigation of EMF and childhood cancer sponsored in part by the U.S. National Cancer Institute, the authors concluded there is,
“little support for the hypothesis that living in homes with (high-time weighted) average magnetic field levels or in homes close to electrical transmission or distribution lines is related to the risk of (childhood leukemia).”
The U.S. Environmental Protection Agency (EPA) and Health Canada, along with other national and international organizations, continue to monitor scientific research on EMFs and human health. Neither agency has released federal guidelines for exposure to EMFs in the home/ living/work environment, in part because of the generally accepted position that the scientific evidence is not strong enough to conclude that typical exposures cause health problems.
Some other organizations have issued exposure guidelines for EMFs at ELF. However, these guidelines are not based on a consideration of risks related to cancer or other health problems; rather, they were established to help product manufacturers and others make sure that the electric currents caused by exposure to EMFs are not stronger than the ones produced naturally by the human body. In addition, many of the appliances and devices that produced EMFs at the higher end of the ELF range have been redesigned since the mid-1990s to reduce the potential for excessive exposure.
For current and additional health information on EMFs issues, visit the National Institute of Environmental Health website or contact other health organizations, the local power company, and/or equipment manufacturers.
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