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Since the invention of the radio the median level of the intensity of electromagnetic fields has increased one million times. The scientific knowledge of the effects this increase can cause on human health are still uncertain.
Sources
Artificial electromagnetic fields can be caused by:
Electrodes
Electrodes are the most worrisome source. High voltage cables in most of the world have a voltage of 132 kV to 380 kV and a frequency of 50 Hz. Below a cable with 380 kV the electric field is of 10 kV/m approximately, moving side ways the tension reduces rapidly at 5 kV/m circa (the limit value of exposition decreed by the DPCM on April 23, 1992).
Within a household the electrical component decrease 10 to 100 times, since it is screened by the house’s structure, but the magnetic field is not shielded.Even the cables of the house’s electrical system, especially if with a closed ring, cause electrostatic fields, due to the difference of power between the conductors, and the electromagnetic fields (caused by the flow of electricity).
Household appliances
In our houses there are many appliances which once activated create electromagnetic fields. These fields fortunately act over a small area (diameter of one meter, more or less), and in most cases are used for short periods of time.
The values of the table are the maximum surveyed per category of appliance and are expressed in
microtelsa:
| Household
appliance |
at
3 cm. |
at
30 cm. |
at
1m. |
| Electric
razor |
1500 |
9 |
0.3 |
| Hoover |
800 |
20 |
2 |
| Hairdryer |
750 |
10 |
0.3 |
| Minipimer |
450 |
40 |
0.2 |
| Microwave |
200 |
8 |
0.6 |
| Florescent
lamp |
200 |
30 |
0.6 |
| Electric
stove |
80 |
4 |
0.2 |
| Washing
machine |
50 |
3 |
0.15 |
| TV |
50 |
2 |
0.15 |
| Iron |
30 |
0.3 |
0.025 |
| Toaster |
18 |
0.7 |
0.01 |
| Dishwasher |
7 |
1 |
0.08 |
| Coffee
machine |
7 |
0.5 |
- |
| Oven |
3 |
0.5 |
0.4 |
| Refrigerator |
1.7 |
0.25 |
0.1 |
Working appliances
Different situations are present in different working environments. In an office the main source of electromagnetic fields are computers, in industries all high temperature processing is at risk, while in the telecommunication industry as well as in research labs the risk of being exposed to waves is higher.
Transmission Antennas
Electromagnetic fields are also a side effect of high frequency technology. In telecommunications there are two main categories of appliances, those that diffuse energy trying to cover the broadest possible surface (radio, TV, etc.) and those that diffuse energy directly covering great distanced in a thin area to a specific point (space communications, DIRECT RADIO COMMUNICATIONS). These fields do not have intensities which are relevant, unless they are placed on the top of a building (see stations for mobile phones).
At last, apparatuses for satellite communications and radar, are appliances which create strong electromagnetic fields, but these are localized and mostly placed away from populated areas.
Effects
According to research done in molecular biology, the electromagnetic field has an important role of coordinator and messenger in the biological processes, sine the interaction between atoms and molecules is an electromagnetic one. By this we can deduce that electromagnetic fields which differ in frequency and intensity from those existing in nature influence and alter our natural biological processes. This causes a condition of stress and electrical disorder within the cells.
The main effects are: alteration of cellular exchanges, cellular damages which may degenerate into tumors and leukemia, fatigue, circulatory problems, nervousness, insomnia, depression.
The exposition to artificial electromagnetic fields is harmful, while exposition to natural fields is biologically useful.
Investigation Methods
In case of severe electromagnetic pollution (ex. close presence of electrodes or transmission antennas) it is best to contact the agencies which carry out environmental analysis.
To carry out measurements of the fields generated within the household there are small but sensitive devices which allow a person to verify the safety of the building.
A leak detector: emits a crackle when it detects a source of electricity.
Electrostatic field meters: measures the intensity of fields generated byappliances in volts per meter.
Magnetic field detectors: allows to measure the magnetic overcharge generated by electric appliances and systems, these are measured in miligauss.
Precautions
To reduce the exposition to fields generated by high voltage cables there are many solutions. The easiest one is to heighten the poles, increasing the distance from the ground, or compacting the cables to a certain extent (more may be dangerous). The most efficient solution would be to bury the cables (there would be a 90% reduction in the electromagnetic field) but there is much opposition to this due to the high costs.
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If we can influence the positioning of the electrodes, we can limit ourselves to a few precautions, particularly if we are buying a house.
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Verify the distance from high voltage cables, the legal restrictions are sufficient ( 10 meters away from a 130 kV cable, 18 meters from a 220kV cable, and 18 meters from a 380 kV cable). Verify the distance from a television relay station and a mobile phone relay station.
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For the household’s electrical system use screened cables and electrical separation devices which turn off the system during hours of
sleep.
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Avoid placing the bed against walls which are lined by electric cables, or where on the other side there is a television, refrigerator, washer, etc.
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Do not leave unnecessary appliances on and turn them of with the central switch, turning off the luminous led.
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Respect the safety distance from the screens (at least one meter)
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Air out rooms during and after the use of household appliances, to disperse the positive
ions.
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