ABSTRACT
Electromagnetic fields
are local electric and magnetic fields that envelop the surrounding space. The purpose of this project is to determine
the EMF exposure of common electric appliances. Eighteen different types of electric appliances were tested at three
different distances; 3 cm, 30 cm, and 100 cm away. Each type of appliance was
tested five times with an EMF meter. In
total, the appliances were measured 270 times. Results show that even though an appliance
was the same type the EMF differed, and the EMF decreased as the distance
increased. The conclusion was that
there was a difference in appliances’ EMF exposure, according to different
types and at different distances away.
INTRODUCTION
Electromagnetic fields are local electric and magnetic fields that envelop the surrounding space. The most widespread source of EMFs is from the movement and consumption of electric power transmission lines, household appliances, electronic devices, and lightning. In a house the walls reduce the electric field levels from those found at similar locations outside the home. There are many electric appliances in the household. Some of the stronger electromagnetic fields are found close to motors and other electrical appliances. Even between apparently similar devices, the strength of the magnetic field may vary a lot. For example, while some hair dryers are surrounded by a field, others hardly produce magnetic fields at all. These differences in magnetic field are related to product design. Computer screens and television sets work on similar principles. Both of them produce static electric fields and alternating electric and magnetic fields at high frequencies. However the screens with crystal displays used in some laptop computers and desktop units do not give rise to significant electric and magnetic fields. Modern computers have conductive screens that reduce the static field. When we sit in front of a television, we are being irradiated with a wide range of electromagnetic frequencies. Electromagnetic radiation is actually given off in all directions from the set. (2)The magnetic field strength around all appliances decreases with distance. Most appliances or items are not operated closely to the body. It has been reported
that at a distance of 30 cm the magnetic field
surrounding house hold appliances are more than 100 times lower than the given
limit of 100microtesla(uT) for the general public. (4) In recent years many national authorities in different countries
have conducted experiments on electromagnetic fields in the environment. None of these surveys have ever concluded that
field levels could bring about diverse health effects. (5) For example, the
user of a mobile phone encounters field levels that are much higher than any
normal living environment. Most researchers
believe even these increased levels do not produce harmful effects. However, electrical hypersensitivity can also be a result of electromagnetic
field radiation. People who are electrically
hypersensitive can react to most types of energy within the electromagnetic
spectrum. The cause of electrical
hypersensitivity is probably very complex, symptoms include: difficulties
in concentration, dizziness, headache, and nausea, teeth, and jaw pains, ache
in muscles and joints and cardiac palpitations. It may depend on frequencies, curve forms are
possibly a combination of fields with different frequencies.(6) The purpose of this project was to determine
the EMF exposure of common electric appliances.
Because it was believed that the magnitude of the EMF exposure will
vary with type and at different distances if the electronic device, the null
hypothesis was the type and proximity of the electronic device does not significantly
affect the EMF exposure.
METHODOLOGY
(1)Five different locations with electronic appliances were used.
(2) Eighteen different devices to be tested were decided on (Refer to Table 1).
(3)They were tested at three different distances; 3 cm, 30 cm, and 100 cm away. (4)Five of each type of appliance was tested with an EMF meter, for a total of 270 measurements.
(5)The data and EMF (uT) was recorded at each of the locations.
(6)When the testing was finished the averages of the
different appliances were determined.
(7)Standard Deviation, and Relative Standard Deviation
for each device was calculated.
RESULTS AND DISCUSSION
The microwave
had the highest mean EMF (uT) at 3 cm away with 5.63, at 30 cm away1.17, and
at 100cm away with 0.15. The copy
machine had the lowest EMF (uT) at 3cm away with 0.04, at 30 cm away with
0.01, at 100cm away with 0.00. For
all appliances the EMF decreased as the distance increased.
The microwave had the highest
Standard Deviation at 3cm away with 2.87(uT), and the scanner had the lowest
SD at 3cm away with 0.01(uT). The
microwave had the highest SD at 30cm away with 0.76(uT), and the fax machine
had the lowest SD at 30cm away with 0.00(uT). The microwave had the highest SD at 100cm away with 1.97(uT), and
the clock had the lowest SD at 100cm away with
0.00(uT).
According to the results
the microwave had the highest mean EMF(uT), and the copy machine had the lowest.
Higher SD means the devices put out different EMF.
The microwave also had the highest SD(uT), and the scanner had the
lowest. There were differences in the different types
of appliances.
CONCLUSION
The results of this study indicate the type and proximity of an appliance does significantly affect EMF exposure. The null hypothesis was rejected. Further work could be done by extending the study to more different types of schools, appliance stores, and homes, along with using even more places with electronic appliances. Also appliances that are not very common could be used.