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Home inspections are important to have done on every home being bought or
sold.
EMFs in the Home
Electromagnetic Fields
Can the electric and
magnetic fields (EMF) to which people are routinely exposed cause
health effects? What are sources of EMFs, and when are EMFs dangerous?
EMF
(or ElectroMagnetic Field) is a broad term which includes electric
fields generated by charged particles in motion, and radiated fields
such as TV, radio, hair dryer, and microwaves. Electric fields are
measured in units of volts per meter or V/m. Magnetic fields are
measured in milli-Gauss or mG. The field is always strongest near the
source and diminishes as you move away from the source. These energies
have the ability to influence particles at great distances. For
example, the radiation from a radio tower influences the atoms within a
distant radio antenna, allowing it to pick up the signal. Despite the
many wonderful conveniences of electrical technology, the effects of
EMF on biological tissue remains the most controversial aspect of the
EMF issue, with virtually all scientists agreeing that more research is
necessary to determine safe or dangerous levels.
Research
since the mid-1970s has provided extensive information on biological
responses to power-frequency electric and magnetic fields. The Electric
and Magnetic Fields (EMF) Research and Public Information Dissemination
(RAPID) Program was charged with the goal of determining if electric
and magnetic fields associated with the generation, transmission, and
use of electrical energy pose a risk to human health. The fact that 20
years of research have not answered that question is clear evidence
that health effects of EMF are not obvious and that risk relationships,
if risk is identified, are not simple. Because epidemiologic studies
have raised concerns regarding the connection between certain serious
human health effects and exposure to electric and magnetic fields, the
program adopts the hypothesis that exposure to electric or magnetic
fields under some conditions may lead to unacceptable risk to human
health. The focus of the program is not only to test, as far as
possible within the statutory time limits, that hypothesis for those
serious health effects already identified, but to identify as far as
possible the special conditions that lead to elevated risk and to
recommend measures to manage risk.
Electromagnetic
hypersensitivity (ES) is a physiological disorder characterized by
symptoms directly brought on by exposure to electromagnetic fields. It
produces neurological and allergic-type symptoms. Symptoms may include,
but are not limited to, headache, eye irritation, dizziness, nausea,
skin rash, facial swelling, weakness, fatigue, pain in joints and/or
muscles, buzzing/ringing in ears, skin numbness, abdominal pressure and
pain, breathing difficulty, and irregular heartbeat. Those affected
persons may experience an abrupt onset of symptoms following exposure
to a new EMF such as fields associated with a new computer or with new
fluorescent lights, or a new home or work environment. Onset of ES has
also reported following chemical exposure. A concerted
effort to provide scientifically valid research on which to base
decisions about EMF exposures is under way, and results are expected in
the next several years. Meanwhile, some authorities recommend taking
simple precautionary steps, such as the following:
-
Increase the distance between yourself and the EMF source – sit at arm’s length
from your computer terminal.
-
Avoid
unnecessary proximity to high EMF sources – don’t let children play
directly under power lines or on top of power transformers for
underground lines.
-
Reduce time spent in the field – turn off your computer monitor and other electrical
appliances when you aren’t using them.
The
Office of Technology Assessment of the Congress of the United States
recommends a policy of “prudent avoidance” with respect to EMF. Prudent
avoidance means to measure fields, determine the sources, and act to
reduce exposure.
-
Detect
EMFs in your home and work environment. It is good to know where the
sources of EMF are in your everyday world and how strong these sources
are. Is there wiring in the wall behind your bed that you don’t even
know about? Is the vaporizer emitting strong fields in the baby’s room?
How much EMF are you and your family getting from the power lines in
the street? Even hair dryers emit EMFs. Home inspectors often have
meters to measure EMFs, or they can be purchased and shared with
friends.
-
Diminish your exposure to
the EMFs you find. Determine how far you must stay away from the EMF
emitters in your home and work environment to achieve less than 2.5 mG
of exposure—the microwave oven, the alarm clock, the computer, and so
on. Rearrange your furniture (especially the beds, desks, and couches
where you spend the most time) away from heaters, wiring, fluorescent
lights, electric doorbells, and other EMF “hot spots.” Where practical,
replace electric appliances with non-electric devices. Where practical,
replace electric appliances with non-electric devices. Have an
electrician correct faulty high EMF wiring and help you eliminate
dangerous stray ground currents. Consult a qualified EMF engineer if
necessary. Contact National Electromagnetic Field Testing Association
at 1-847-475-3696 for consultants in your area.
-
Shield
yourself. Use shielding devices on your computer screen and cellular
phone. Add shielding to your household wiring, circuit box, and
transformers.
Magnetic fields are not blocked
by most materials. Magnetic fields encountered in homes vary greatly.
Magnetic fields rapidly become weaker with distance from the source.
- Electric fields in the home, on average, range from 0 to 10 volts
per meter. They can be hundreds, thousands, or even millions of times
weaker than those encountered outdoors near power lines.
- Electric
fields directly beneath power lines may vary from a few volts per meter
for some overhead distribution lines to several thousands of volts per
meter for extra high voltage power lines.
- Electric fields from power
lines rapidly become weaker with distance and can be greatly reduced by
walls and roofs of buildings.
The chart on the left summarizes data from a study by the Electric
Power Research Institute (EPRI) in which spot measurements of magnetic
fields were made in the center of rooms in 992
 homes throughout the
United States. Half of the houses studied had magnetic field
measurements of 0.6 mG or less, when the average of measurements from
all the rooms in the house was calculated (the all-room mean magnetic
field). The all-room mean magnetic field for all houses studied was 0.9
mG. The measurements were made away from electrical appliances and
reflect primarily the fields from household wiring and outside power
lines.
If you are comparing the information in this chart with measurements
in your own home, keep in mind that this chart shows averages of
measurements taken throughout the homes, not the single highest
measurement found in the home.
Magnetic
fields close to electrical appliances are often much stronger than
those from other sources, including magnetic fields directly under
power lines. Appliance fields decrease in strength with distance more
quickly than do power line fields.
The following table, based on data gathered in 1992, lists the EMF
levels generated by common electrical appliances. Magnetic field
strength (magnitude) does not depend on how large, complex, powerful,
or noisy the appliance is. Magnetic fields near large appliances are
often weaker than those near small devices. Appliances in your home may
have been redesigned since the data in the table were collected, and
the EMF they produce may differ considerably from the levels shown here.
 |
The
graph shows magnetic fields produced by electric blankets, including
conventional 110-V electric blankets as well as the PTC (positive
temperature coefficient) low-magnetic-field blankets. The fields were
measured at a distance of about 2 inches from the blanket’s surface,
roughly the distance from the blanket to the user’s internal organs.
Because of the wiring, magnetic field strengths vary from point to
point on the blanket. The graph reflects this and gives both the peak
and the average measurement. |
|
Sources of Magnetic Fields (mG)* |
| | Distance from source | | |
6" |
1' |
2' |
4' |
|---|
| Office Sources | AIR CLEANERS
Lowest
Median
Highest | 110
180
250 | 20
35
50
| 3
5
8 | -
1
2 | COPY MACHINES
Lowest
Median
Highest | 4
90
200 | 2
20
40
| 1
7
13 | -
1
4 | FAX MACHINES
Lowest
Median
Highest | 4
6
9 | -
-
2
| -
-
- | -
-
- | FLUORESCENT LIGHTS
Lowest
Median
Highest | 20
40
100 | -
6
30
| -
2
8 | -
-
4 | ELECTRIC PENCIL
SHARPENERS
Lowest
Median
Highest |
20
200
300 |
8
70
90
|
5
20
30 |
-
2
30 | VIDEO DISPLAY TERMINALS
(PCs with color monitors)**
Lowest
Median
Highest |
7
14
20 |
2
5
6
|
1
2
3 |
-
-
- | | Bathroom Sources | HAIR DRYERS
Lowest
Median
Highest | 1
300
700 | -
1
70
| -
-
10 | -
-
1 | ELECTRIC SHAVERS
Lowest
Median
Highest | 4
100
600 | -
20
100
| -
-
10 | -
-
1 |
|
| | Distance from source | | |
6" |
1' |
2' |
4' |
|---|
| Workshop Sources | BATTERY CHARGERS
Lowest
Median
Highest | 3
30
50 | 2
3
4
| -
-
- | -
-
- | DRILLS
Lowest
Median
Highest | 100
150
200 | 20
30
40
| 3
4
6 | -
-
- | POWER SAWS
Lowest
Median
Highest | 50
200
1000 | 9
40
300
| 1
5
40 | -
-
4 | ELECTRIC SCREWDRIVERS
(while charging)
Lowest
Median
Highest |
-
-
- |
-
-
-
|
-
-
- |
-
-
- | | Living/Family Room Sources | CEILING FANS
Lowest
Median
Highest | | -
3
50
| -
-
6 | -
-
1 | WINDOW AIR CONDITIONERS
Lowest
Median
Highest | | -
3
20
| -
1
6 | -
-
4 | COLOR TELEVISIONS**
Lowest
Median
Highest | | -
7
20
| -
2
8 | -
-
4 |
|
|
Sources of Magnetic Fields (mG)* |
| | Distance from source | | |
6" |
1' |
2' |
4' |
|---|
| Kitchen Sources | BLENDERS
Lowest
Median
Highest | 30
70
100 | 5
10
20
| -
2
3 | -
-
- | CAN OPENERS
Lowest
Median
Highest | 500
600
1500 | 40
150
300
| 3
20
30 | -
2
4 | COFFEE MAKERS
Lowest
Median
Highest | 4
7
10 | -
-
1
| -
-
- | -
-
- | DISHWASHERS
Lowest
Median
Highest | 10
20
100 | 6
10
30
| 2
4
7 | -
-
1 | FOOD PROCESSORS
Lowest
Median
Highest | 20
30
130 | 5
6
20
| -
2
3 | -
-
- | GARBAGE DISPOSALS
Lowest
Median
Highest | 60
80
100 | 8
10
20
| 1
2
3 | -
-
- | MICROWAVE OVENS***
Lowest
Median
Highest | 100
200
300 | 1
4
200
| 1
10
30 | -
2
20 | MIXERS
Lowest
Median
Highest | 30
100
600 | 5
10
100
| -
1
10 | -
1
1 |
|
| | Distance from source | | |
6" |
1' |
2' |
4' |
|---|
| Kitchen Sources | ELECTRIC OVENS
Lowest
Median
Highest | 4
9
20 | 1
4
5
| -
-
1 | -
-
- | ELECTRIC RANGES
Lowest
Median
Highest | 20
30
200 | -
8
30
| -
2
9 | -
-
6 | REFRIGERATORS
Lowest
Median
Highest | -
2
40 | -
2
20
| -
1
10 | -
-
10 | TOASTERS
Lowest
Median
Highest | 5
10
20 | -
3
7
| -
-
- | -
-
- | | Bedroom Sources | DIGITAL CLOCK****
Lowest
Median
Highest | | -
1
8 | -
-
2
| -
-
1 | ANALOG CLOCKs
(conventional clockfare)****
Lowest
Median
Highest | |
1
15
30 |
-
2
5
|
-
-
3 | BABY MONITOR
(unit nearest child)
Lowest
Median
Highest |
4
6
15 |
-
1
2
|
-
-
- |
-
-
- |
|
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