7 questions about electromagnetic fields - Pieuvre.ca

7 questions about electromagnetic fields – Pieuvre.ca

Electromagnetic fields have been a cause for concern for several years. To better discern what is true from what is false, the rumor detector summarize here what you need to know about them.

1) What is an electromagnetic field?

Every atom in the Universe is made up of at least protons and electrons. These particles have an electrical charge (positive and negative, respectively). And any charged particle produces an electric field. In the case of the electron, the electric field corresponds to the force with which one electron repels another in a precise place.

When charged particles move, as in the case of an electric current, they create a magnetic field. A changing magnetic field can also generate an electric field.

In other words, magnetic and electric fields are intimately linked and form electromagnetic fields. As they propagate through space, these fields take the form of waves.

2) What are the sources of electromagnetic fields?

Therefore, electromagnetic fields are present everywhere on our planet and in the cosmos. Just think of the magnetic field that surrounds the Earth or the electric fields generated in the atmosphere by storms. Furthermore, any form of matter emits electromagnetic radiation. This is, among others, the case of the soil and the human body.

With modern technologies, for a century and a half there have been artificial sources of electromagnetic fields, whose frequencies are much lower than those we can find in nature: transmission lines, appliances and electric currents in our homes. Radio or television antennas, wireless Internet routers, cell phones, microwave ovens also fall into this category.

3) How do we measure the energy level of waves?

Therefore, the movement of an electromagnetic field has the form of a wave. These waves are often illustrated as meandering lines with a “peak” and a “trough”. Sometimes we speak of “wavelength”, which is the distance between two “peaks”, sometimes of “frequency”, which is the number of “peaks” per second. Therefore, the shorter the wavelength (the distance between two peaks), the higher the frequency.

You should also know that the higher the frequency of an electromagnetic wave, the higher its energy level. This separates electromagnetic radiation into two categories.

High frequencies: At the higher end of the spectrum, we find so-called “ionizing” radiation, such as ultraviolet rays, X-rays, and gamma rays. According to the National Institute of Public Health of Quebec (INSPQ), only these have enough energy to break down organic molecules such as DNA.

Low frequencies: At the other extreme, there are non-ionizing types of radiation. This term means that the waves included in this portion of the electromagnetic spectrum do not have the necessary energy to “ionize” atoms and molecules, that is to say “break” their chemical bonds: their influence is rather linked to the heat they emit (“the thermal effect “). We find in this category radio frequencies (such as 5G), microwaves and light that we can all see. It is this low energy level that makes this type of radiation considered harmless to health.

Electromagnetic Waves - Infographic 2

4) Does intensity vary with distance?

Also, remember the WHO, the electromagnetic field decreases rapidly when you move away from it. In this regard, it should be noted that, in the case of electrical appliances, as soon as one is more than 30 cm away, the intensity of the field is much lower than the established standards to avoid thermal effects.

Also, the intensity of electromagnetic radiation from radio or TV antennas, wireless Internet routers, or microwave ovens is relatively low compared to that from cell phones or cordless phones, notes the INSPQ. In fact, the exposure is higher with these devices since they are worn close to the body.

5) Has exposure to electromagnetic fields increased?

The WHO also explains that exposure to electromagnetic fields has gradually increased over the last 20me century due to the growing demand for energy and technological advances. However, the INSPQ pointed out in 2016, the arrival of new mobile phone technologies in recent years would not have contributed to increasing exposure to radio frequencies, compared to the arrival of the first systems in the 1980s “that have increased significantly.” In addition, according to another INSPQ document, specifically dedicated to 5G, the arrival of the latter should not significantly change exposure to radio frequencies, since the technology is based on a multiplication of antennas that will emit, over short distances, waves of much smaller frequency. intensity.

6) What are the known effects of exposure to electromagnetic fields?

It should be remembered that after decades of research on the subject, the main biological effect of electromagnetic fields has been measured. in the human body, it is thermal in nature, in other words, heat.

When the intensity of exposure is very high, these fields could increase body temperature, according to the International Commission on Non-Ionizing Radiation Protection (ICNIRP). If the exposure is very localized, it could cause pain and burns. In addition, Italian researchers who have studied the risks for workers of being exposed to electromagnetic fields, point out that the heat could also cause the appearance of cataracts in the eyes.

However, at low exposure levels like those we are exposed to on a daily basis, the heat generated is not enough to cause this type of damage, ICNIRP notes.

The National Institute of Public Health of Quebec (INSPQ) also points out that we are well aware of the effect of radiofrequencies when levels are very high. This knowledge has been used by regulatory agencies to set limits. However, the radiation produced by the technologies that surround us is much lower than the permitted limits.

In its 2016 document, the WHO also notes that low-frequency electromagnetic fields are generally too weak to affect health. “During the last 30 years, about 25,000 scientific articles have been published on the biological effects and medical applications of non-ionizing radiation… Current data does not in any way confirm the existence of health effects resulting from non-ionizing radiation. exposure to low intensity electromagnetic fields. »

INSPQ acknowledges, however, that some scientific uncertainty remains regarding the possible long-term effects of cell phones. For example, a study published in 2020 by the United States National Toxicology Program found that high-dose radiofrequency exposure was associated with the development of tumors in rats. However, these results are not necessarily applicable to humans, as the level and duration of exposure were significantly higher than when using a phone.

7) Did the fear of electromagnetic fields start before cell phones?

If we go back to the 1980s, we can attribute this fear to two authors, who were interested in power lines. The epidemiologist David Savitz, author of the first study, in 1987, raising the possibility of an increase in the rate of cancers in children, and above all, the American journalist Paul Brodeur. The latter made this topic his battle horse until 1992 and published several texts affirming the existence of an association between power lines and leukemia in children.

All subsequent public health studies would show that there were no more leukemias in the neighborhoods located near the power lines. Even David Savitz acknowledged that the data obtained after the publication of his study allowed turning the page.

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