Often we hear discussions that talk about electromagnetic pollution, but the argument is very complex in its physic field to understand correctly what it means.
So, we try to explain correctly the meaning of terminology and key issues.
Earth has always been surrounded by a natural static magnetic field, that in addition to offering wonderful natural shows like auroras, protect us from cosmic rays forming a kind of shield around the Earth.
But, in these last years, in addiction to natural magnetic field, there are other artificial magnetic fields like: electricity transport and use systems, like power lines and household appliances, or communication systems of radio, TV, phone signals. All of this caused modification (pollution) of natural magnetic field.
With the term electro smog we describe electric, magnetic and electromagnetic pollution due to electromagnetic radiation not ionizing.
The main problem of this form of pollution is, in addiction with less information, also with less reliable data that bind health damage to electromagnetic wave exposure.
If for low frequency (power lines and transformation cabins) different studies have certain results (increasing of childhood leukaemia, lymphatic leukaemia due to exposition to magnetic fields with induction higher than 0,4 μT). We cannot say the same thing about high frequencies (mobile phones, radio TV antennas, etc…) with inaccurate and not unique data.
As regard law frequency the main problem is the site of power lines: near houses or schools or places where citizens stopping in for a long time.
As regards high frequency, laws propose to identify, through zonation, suitable or not suitable areas for installations, guarantying the use of innovative technologies that can minimize exposition and provide to delocalization of radio – TV station.
Often these provisions of law aren’t performed and it is for this reason there is high electromagnetic pollution in our houses.
EFFECTS OF ELECTROMAGNETIC POLLUTION ON HUMANS
Now we speak about the most critical topic: correlation between electromagnetic pollution and possible damage on human health.
As said EMF sources are everywhere, even we stay at home we are surrounded by electromagnetic fields that may be more or less harmful for our health.
We must divide electromagnetic field in different frequency and then explain what happens, or may happen, if a person exposes himself to them.
There are two types of effects:
- Short time effects: thermic effect due to exposition to electromagnetic waves (for example waves that hit mobile phone users);
- Long-time effects: stresses that if repeated over time can cause biological damages.
We can give another definition:
- Acute or immediate effects (due to medium – high intensity exposition for a short time period);
- Delayed or chronic effects (due to law intensity exposition for a long period).
A subdivision on effects due to EMF is on its class:
- Effects induced by low frequency fields;
- Effects induced by radio frequency (RF) and microwave (MW).
Another subdivision is:
- Thermic effects: due to an increase of temperature of exposes system, caused to the energy transfer between EMF and biological tissue;
- Not thermic effect: they are not bound to the increase of temperature but they are characterized by different trouble (neoplasms, interactions with the central nervous system, etc…).
LOW FREQUENCY FIELD EFFECTS
For EMF of low frequency all the effects are specific effects like: burns, ventricular fibrillation.
For electric field value of 2 – 10 kV/m the subject notes the field (vibration of the piliferous system), for electric field above 10-20 kV/m and of magnetic field of 5 – 10 mT the effects are on visual and nervous system, muscles stimulation, etc…
In the document of National Institute for Environmental Health Sciences (Portier e Wolfe, 1998), that gives an evaluation of these effects using parameters proposed by International Agency Research on Cancer (IARC), appears that it is possible that there is a correlation between carcinogenic effect for childhood leukaemia and exposition to low frequency field at home and for lymphatic leukaemia and exposition at work for values above 0,4 μT.
On these considerations low frequency field are classified in the “possible carcinogens” class (B group of IARC).
Studies’ results argue that it is better adopt the attention value of 0,5 μT.
HIGH FREQUENCY FIELD EFFECTS
Compared with EMF for low frequency, the action of EMF between 100 kHz and 300 GH (high frequency) are more evident because the effects are acute thermic effects due to the exiting of molecules under EMF effects. The problem remains on characterization of the effect on long time period.
Biological tissue may be a conductor or a dielectric in order to EMF frequency considered.
Temperature increasing of a particular and sensible organ can cause serious biological problems:
for eyes there are coagulation phenomenal (cataracts).
Reproductive organs are sensible to the temperature increasing, they may become temporarily sterile. There are other negative effects like: blood disorders, damage to chromosomes, disorders of the cardiovascular and digestive system.
For long time effects data are insufficient, this may be a problem for the correlation of specific health effects and electromagnetic field exposition.
However these studies are a data base sufficient to justify the adoption of precautionary policies.
Due to the increase of telecommunication system there is a higher exposure to electromagnetic field produced by them.
It is recommended to use precautionary principle to define rules and strategies to minimize population exposure levels to this kind of pollution.