FREQUENT QUESTIONS ABOUT RADIATION
What is electromagnetic radiation (EMF)?
By the term electromagnetic radiation, scientists mean the transfer of energy in the form of electromagnetic waves, ie electric and magnetic waves that propagate simultaneously in space at the speed of light. The different types of electromagnetic radiation are distinguished from each other depending on the frequency or wavelength of the propagating wave. Frequency is measured in Hz (oscillations or cycles per second).
Are there many types of electromagnetic radiation?
Although most people associate electromagnetic radiation with technology and electronic devices, electromagnetic radiation is a natural phenomenon. For example, sunlight or heat emitted by a hot body are forms of electromagnetic radiation. Of course, electromagnetic radiation is also X-rays, radio waves or the signal of mobile phones. What differentiates them is the energy they carry and how easily material obstacles can pass through. The figure shows the full range of electromagnetic radiation. The higher the frequency of a radiation, the more energy it carries.
In which cases do we have exposure to electromagnetic radiation?
We are surrounded by natural sources (earth electromagnetic field, sunlight, etc.) or artificial sources (mobile phones, electrical appliances, etc.) emitting electromagnetic radiation, so our exposure to it is daily.
Is electromagnetic radiation dangerous?
The answer is yes and no. It depends on the type of electromagnetic radiation, its intensity and the time of exposure of an organism to it. Sunlight is not dangerous and thanks to it we can see the world around us. However, as we all know it can be harmful in the summer months after prolonged exposure to it. X-rays and radioactivity on the other hand are dangerous radiation even in short-term exposure because they have a lot of energy and easily enter our body and are called ionizing radiation. Radio waves (radio, wireless, etc.) carry small amounts of energy and are considered safe for organisms.
In addition, the degree of danger depends on the body that receives the radiation. An adult and an infant have different tolerances. For this reason, it is easy to see why ultrasound (sound waves that do not charge at all) are used instead of X-rays for doctors to monitor the condition of the fetus in the pregnant woman's abdomen.
Which are the conseguences of the "dangerous" radiations?
There are two main ways electromagnetic radiation can affect an organism.
The first is the increase in temperature of the part of the body that receives the radiation. Remember that electromagnetic radiation carries energy. When a body receives this energy it is converted into heat in the body's cells. Prolonged rise in cell temperature can cause problems with normal functioning. This mode of action mainly involves non-ionizing electromagnetic radiation such as sunlight or radio waves.
Ionizing radiation such as radioactivity and X-rays due to their very high energy and penetration, enter the cells and can immediately cause serious damage to the function of organisms such as mutations in genetic material, destruction of enzymes, etc. We all know that radioactivity is extremely dangerous and exposure to it is prohibited. X-rays are also used sparingly by doctors and when appropriate, to limit patients' unnecessary exposure to them.
Are there exposure limits to electromagnetic radiation?
Yes, exposure limits to electromagnetic radiation have been set. Of course, they vary depending on the type of radiation and the age of the person. For strong radiation such as radioactivity, exposure to them is completely prohibited, unless it is done for therapeutic reasons by specialized doctors (radiotherapy). For other types of radiation, so-called non-ionizing radiation, international safe exposure limits have been set by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). Based on the ICNIRP limits, each state adopts national case law setting the permissible radiation exposure limits. In Greece, Law 3431/2006 imposes restrictions on the conditions for the installation of transmitting antennas, setting 70% of the ICNIRP limits as ceilings, while if at a distance of less than 300 meters there are nurseries, schools, nursing homes, or hospitals, the levels Exposure to the public is prohibited to exceed 60% of the ICNIRP limits. In Greece, the body responsible for control and accreditation is the Democritus Hellenic Atomic Energy Commission.
Is the electromagnetic radiation emitted by mobile phones or other household appliances (cordless phones, cordless routers, microwave ovens) ultimately dangerous or not?
the answer is yes and no. Before you continue, consider that even sunlight can be dangerous when the exposure to it is long lasting especially during the summer months. Mobile phones emit non-ionizing radiation, which is generally considered safe for limited exposure. However, do not forget that the manufacturers themselves recommend not to use the device for long hours in direct contact with the head, to use cables or Bluetooth, and to limit the use of mobile phones by children as much as possible. Also , home appliance manufacturers that emit E / M radiation recommend that cordless telephone bases and wireless routers not be placed near beds and bedrooms.
Is radiation from mobile phones and base stations radioactive?
Electromagnetic radiation from mobile phones and mobile base stations has nothing to do with radioactivity. It belongs to the non-ionizing radiation, ie the radiation that is impossible to cause ionization of the molecules and to break chemical bonds.
What physical quantities define the intensity of the radiation emitted by a mobile base station?
There are three physical quantities that describe the intensity of electromagnetic radiation:
- electric field strength (V / m)
- magnetic field strength (A / m) and
- power density (W / m2).
Mobile Telephony Base Stations - Shouldn't the Limits Be Respected?
Limits must be respected. A prerequisite for a product to enter the market is to meet certain specifications, including compliance with radiation limits. The SAR standard has been introduced for mobile phones, but only for thermal effects caused by electromagnetic radiation.
What about Mobile Antennas or High Voltage Lines?
In this case, too, there are limits that must be met in order to install a mobile telephony antenna - the law determines the shortest possible distance from residential areas. Of course, the limits and distances depend on the power and frequency at which the antenna transmits. These limits are stricter when sensitive population groups: schools, kindergartens, hospitals, etc, are within a short radius.
Greek Legislation Reference Levels in various frequency ranges as they result in a reduction rate of 70% and 60% of the ICNIRP limits for equivalent flat wave hip density (P).
| Frequency Area |
70% | 60% | Applications |
| Ρ (μW / m2) | Ρ (μW / m2) | ||
| 10-400MHz | 1,400,000 | 1,200,000 | FM radio, TETRA communications, VHF broadcasts, etc. |
| 600 MHz | 2,100,000 | 1,800,000 | UHF TV shows |
| 800 MHz | 2,800,000 | 2,400,000 | |
| 900 MHz | 3,100,000 | 2,700,000 | GSM-900 mobile telephony |
| 1800 MHz | 6,300,000 | 5,400,000 | GSM-1800 mobile telephony |
| 2-300GHz | 7,000,000 | 6,000,000 | UMTS mobile telephony, microwave links, satellite communications |
Is the radiation from high voltage lines and electrical appliances the same as that from mobile base stations?
at the transmission and distribution lines of electricity, electric and magnetic fields are created that do not have the form of an electromagnetic wave and change in the frequency of 50Hz (low frequency), similar to the fields created in the environment of all electrical devices connected to the electrical network. The electromagnetic radiation emitted by mobile phone systems is in the form of an electromagnetic wave and varies with a high frequency of 700 MHz and above. This results in electric and magnetic fields from high voltage lines and electromagnetic fields in the mobile antenna environment having different physical properties and different biological effects. That is why their measurement and study requires separate and different instruments.
Are we safe?
No one can answer this for sure. For three main reasons:
Α. First, these limits were introduced taking into account only the thermal effects of radiation on organisms. In recent years, more and more scientists and experts are revising the prevailing view that low-frequency radiation causes only thermal effects in organisms. There is growing scientific evidence that long-term exposure to low-frequency radiation could cause other problems. For this reason, the World Health Organization has classified low-frequency electromagnetic radiation as a "potentially carcinogenic" agent. Before rushing to dispose of your mobile phone, note that the coffee and exhaust gases of car internal combustion engines belong to the same category. However, many international scientific organizations and bodies recommend that lower exposure limits be observed, given that low-frequency E / M radiation can have other effects besides rising temperatures. For example, BIOINITIATIVE, an international collaboration of biosafety scientists, has set safe limits of 3-6μw / m2 , while the German Building Biologists Association, one of the most authoritative and recognized internationally in matters of electromagnetic safety, recommends following the instructions in the table below.
| No worries | Minimal concern | Serious concern | Excessive anxiety |
| & lt; 0.1μW / m2 | 0.1μW / m2 to 10μW / m2 | 10μW / m2 to 1000μW / m2 | & gt; 1000μW / m2 |
& nbsp;
Β. The second reason why you can not be sure if you are safe from electromagnetic radiation is that there are no long-term statistics on the effects of electromagnetic radiation on humans . This is due to the fact that only in the last 20 years low frequency electromagnetic radiation (mobile phones, cordless phones, wireless internet) have entered our daily lives.
Γ. Third, compliance with the limits set by the ICNIRP and followed by national governments is not always possible due to the lack of thorough controls or due to the ignorance and indifference of citizens who choose to live or work near strong sources of radiation. > The example in the picture is revealing. Would you live in this house or send your children to a school under high voltage cables?
What can I do to be safe about radiation and electromagnetic charges?
First, follow the advice and instructions of home appliance and mobile phone manufacturers. With regard to mobile telephony antennas or PPC high voltage lines, you can ask for a measurement of the radiation received by your space from a special workshop. If the urban planning rules have been observed and the antennas are legally licensed, the most it is possible that the radiation you receive is within the permissible limits set by law.
What if the measurements show that the official radiation limits have been exceeded or if I wish to follow more strict limits that the proposed ones?
The solution in this case is to shield your space with special protective materials that will eliminate the percentages of electromagnetic radiation entering your home. The shielding is done by a special workshop and its effectiveness is confirmed by a new measurement of electromagnetic radiation after installation . Shielding is a relatively economical process and does not require special construction work (consits for example on applying specific special paint on your external/internal walls, protective transparent films on the windows, special curtains, electrical grounding equipment etc). The inconvenience would be as much as painting some walls or changing some windows.
Having implemented a radiation shielding in my space, will my mobile still be able to receive a good signal in my premises?
All though following a radiation shielding process will drastically cut the signal, your cell phone will be able to catch enough signal in order to operate. Consider that a cell phone needs only 0.1 μW / m2 to have a full signal, that is, as much as the safest value set by the SMB.
What is the specific absorption rate (SAR)?
Been exposed to electromagnetic radiation, a quantity of this energy is absorbed by our body. Specific Absorption Rate (SAR) expresses the power absorbed per unit mass of the body. The average full-body SAR expresses the average value of energy absorbed throughout the body, and the SAR on the head and torso, as well as the extremities, refers to the local absorption in these limbs. For reference mobile phones use the local SAR for the head area and in the case of base stations the average full body SAR.
What does the absorption of energy by the human body depend on?
A person's exposure to electromagnetic radiation results in the absorption of part of it by the human body. The amount of energy absorbed depends on the intensity and frequency of the radiation, but also on factors such as weight, body height, under what conditions the exposure took place such as direction of radiation, distance, duration, whether the exposure is local or full body as well as the age and condition of the person children, pregnant, elderly
