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Electric
And Magnetic
Fields
 As we progress
into the twenty first century, the impact of our technology on
the environment and our health has become an issue of major concern. These are no longer
issues left to just the environmentalists, and industry. They are now a concern to home
buyers as well.
One such issue that has concerned home buyers in recent years is the effects of
electric and magnetic fields (EMF) on human health. Is there
reason for concern? To what degree should this concern be? The information that follows
was taken from material provided by both the power companies and the Connecticut
Department of Public Health and Addiction Services. We hope it helps to answer some of
your questions.
What
is EMF
EMF stands for electric and magnetic fields. They are not the
same, but they both come from the same source, although different aspects of that source.
The electricity we use in everyday life, from our homes to our businesses consists of
voltages and currents. These alternate level and direction at a frequency of 60 cycles per
second (60-Hz). This 60-Hz produces electric and magnetic fields.
Electric Fields
are produced by voltage.
Voltage moves electricity through the wire. These fields are present where- ever there is
electricity, even when the appliances these wires lead to are shut off. Electric fields
diminish rapidly from their source and can be blocked by objects. Trees and the walls of
your house will block these fields from entering your home from outside power sources.
Magnetic Fields
are produced by current
flowing through the wire. These fields only exist when there is current flowing. If
you turn off an appliance the magnetic field is no longer present.
The significant difference between these two fields is that electric fields can and are
blocked by objects while magnetic fields are not. For this reason nearly all the concern
over health risks has been in relation to magnetic fields rather than electric fields.
This is the area of ongoing studies by the scientific community and the focus of the
following information in relation to their source and risk of exposure.
Going
to the Source
When speaking about magnetic fields, their units of measurement are
referred to as a Gauss. Magnetic fields are measured in one one thousandth of a gauss -
milliGauss (mG). The level of background field in the average home is 1.0 mG. These
fields, generated in the home come from a number of sources, such as your television,
light fixtures, clothes dryer and any other home appliance. Whether they are generated
from within the home or from an outside source, they drop off rapidly from that source. A
television will measure from 8 to 20 mG within 1.5 inches and drop off to 0.1 to 1 mG at
39 inches away.
Exterior sources of EMF
Transmission power lines of high voltage carry electricity from
generation plants to substations and to interconnect neighboring utility systems. These
are large cross country lines. Directly under these lines fields will measure 57.5mG
dropping to 1.8 200 ft. away.
Distribution lines are those which carry electricity from
substations to homes, schools and businesses. At the source these will read about 29.7 mG
and drop to 1.7mG at 100 ft.
With all of our modern electronic conveniences, it would be impossible to live free of
all magnetic fields. Before becoming a hermit, continue
to read and find out what the known
health risks are at this time.
Health Risks
Is EMF a health risk?
The EPA as of this writing has not taken a position on EMF but refers
studies done by other agencies. These studies have concluded, that describing ELF (extremely
low frequency) EMF as “possibly” carcinogenic is a conservative
public health decision based on “limited evidence…"
The lack of conclusive results provoke only a need for
further investigation. A 1992 EPA report noted that "although the existing evidence
does not prove a current cause-effect relationship for EMF exposure and human disease, it
does suggest the need for further research to allow for a realistic evaluation of the
possibility of public health risks and assessment of their potential magnitude".
There are three types of research studies evaluating the possible
effects of EMF as a health risk.
1. Epidemiology - studies various human population exposed to EMF.
2. Laboratory studies - exposing animals or humans to EMF to look for possible effects
that it may cause.
3. Laboratory studies exposing single cells of tissue to EMF
fields, looking for any changes or effects. Although some changes have been
noted in these laboratory studies, it is difficult to say whether or not
they are negative or will lead to a health problem.
The information
contained on this page is not exhaustive and is meant to be only an
overview. For complete documentation on this subject please contact
local or State heath officials.
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