PhD Dragan Poljak, Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture, Split
Electromagnetic fields of electronic communications networks and impact on human beings and the environment
Ionizing radiation contains sufficient amounts of energy to break atoms, that is, to break the chemical bonds and release electrons and create electrically charged particles – ions. Ionizing radiation, depending on the dose or degree of irradiation, may have a harmful effect on biological systems.
Ionizing and non-ionizing radiation is separated in the electromagnetic spectrum, and the delimitation of these two phenomena is at frequencies of approximately 1015Hz.
In short, regarding non-ionizing radiation, it can be said that low frequency fields due to large wavelengths do not have thermal effects on humans, that radio waves in higher parts of the spectrum, because their wavelengths are comparable to the body, penetrate the organism and warm up the tissue. High frequency fields in the 5G frequency range do not penetrate the body much, but they mostly remain on the body surface, so the power density absorbed on the body surface can be associated with local surface heating.
It is entirely up to biomedical scientists to connect the temperature increase on the surface of the body (due to absorbed strength) with possible consequences for human health.
On the other hand, at GHz frequencies, especially over 6 GHz, the depth of field penetration into tissues is low, so SAR is no longer an appropriate measure for determining the absorption of energy in the body. In this case, the absorbed power density of the electromagnetic field is much more appropriate as the dosimetry size. The correlation of the average absorbed power density (caused by the outer intrusion field) on the body surface with the surface temperature rises is the basis for guidelines in protecting people against the radiation of 5G generation devices.
So instead of warming tissue inside the body due to penetration of the electromagnetic wave, the radiation effect of the 5G system is local heating on the surface of the body.
The rigorous mathematical definitions of the absorbed power density on the body surface have been set up and the so-called thermal factors that local temperature rises on the body surface with the absorbed power density on the body surface are the main mission of the international IEEE working group, which has been working on it for a year now, and of which I am a member. Several official publications are being prepared, which will present the group's work in prestigious journals.
What are the differences in the work and EM radiation of modern wireless communications (e.g. Wi-Fi, Bluetooth, mobile communications)?
In the case of new 5G services, it is necessary to implement a large number of densely installed base stations operating in the area of millimeter waves (in the GHz frequency range), since the radiation of 5G systems is shorter in range. The consequence of an increased number of radiation sources is the accumulation effect in the absorption of electromagnetic energy, i.e. the additive effect on tissue heating (dominant effect of high frequency fields). On the other hand, the dosimetry of the incident field in previous mobile communication systems (2G/3G/4G) was carried out using relatively simple procedures, both experimental and computer dosimetry. Considering the exceptional complexity of the upcoming mobile communication 5G systems, it is clear that the sophistication of mathematical models will become an indispensable item considering that radiation sources are complex MIMO antenna systems whose radiation diagrams depend on the desired capacity and speed of data transmission, and are focused on the end user and, moreover, change with regard to the target user. This points to the inevitable fact that stochastic modelling of radiation sources in the form of 5G systems will become a necessary step in the assessment of realistic levels of incident fields to which human is potentially exposed.
Are there certain precautions and how to apply them?
Precautionary measures mainly consist of adherence to safety guidelines prescribing different types of restrictions, which can in principle be divided into limits on quantities generated in the body due to the impact of external fields and consequently restrictions on external fields. Finally, these measures, for each specific case, are reduced to a certain safety distance from the radiation source depending on the declared power of the antenna system and taking into account the relative position of the source in relation to the human, for example whether the human is in the direction of the maximum of the main beam of the radiation diagram.
Studies on the harmfulness and impact of 5G mobile communications networks
The international body whose guidelines for the protection against non-ionizing radiation are followed by the majority of EU members is the International Commission on Non-Ionizing Radiation Protection (ICNIRP).
Guidelines prescribed by the ICNRP (ICNIRP Guidelines for Limiting Exposure to Electromagnetic Fields (100 kHz to 300 GHz)) published in March 2020, in summing up the findings available from recent biomedical literature regarding the assessment of harmfulness to the health of non-ionizing fields, say: the only documented adverse health effects caused by exposure to radio-frequency electromagnetic fields are nerve stimulation, the changes in cell membrane permeability and the effects of temperature increase.
It should be stressed that these are updated guidelines constituting the amended ICNIRP document of April 1998.
It should also be stressed that there are biomedical scientists who dispute the ICNIRP conclusions, usually arguing that it is necessary to take into account the non-thermal effects and long-term exposure to fields. As I have already pointed out, only biomedical scientists are relevant for some answers, and the multidisciplinary working groups are, in my opinion, necessary to answer a number of questions related to non-ionizing radiation.
Are there studies on the impact of 5G networks on human organisms and their harmfulness?
The issue of potential harmfulness of this type of radiation should be addressed to biomedical scientists. In principle, the existing dosimetry studies and protective guidelines in a way covered the entire part of the electromagnetic spectrum that is significant for non-ionizing fields, i.e. frequencies below 300GHz. However, it should be noted that in recent decades low frequency bands have been of particular interest related to the analysis of powerlines and transformer stations, and high frequencies, concerning the analysis of GSM and UMTS systems. In this regard, the above-mentioned SAR size was widely used in terms of the power averaged over mass and consequently local tissue heating. Since, at GSM frequencies wave penetrates into the organic matter, SAR is averaged over the control volume. On the other hand, since surface effects occur at 5G frequencies, instead of penetration into a biological object, SAR is no longer used in terms of the analysis of these phenomena, but the density of absorbed power. In particular, to protect humans from heat effects, local SAR is averaged on a volume of 10 g, while the latest thermal impact studies suggest the use of averaged area of 1 cm2 to 4 cm2 (depending on frequency range) for absorbed power density. Correlation of surface temperature rise with the average absorbed power density represents the basis for guidelines in protecting people from 5G radiation, i.e. for conducting appropriate biomedical studies. Overview and critical review of a number of recent studies related to potential field harmfulness in the GHz frequency range is available in the previously mentioned updated ICNIRP guidelines.
There are really different studies. A large number is of a statistical-epidemiological character, which means that it is difficult to establish a causal link between exposure to fields of certain frequencies and possible health problems. In these studies there are several aggravating factors. First, it is not possible to perform experiments on live humans along with the development of theoretical models, and the extrapolation of experiments on animals or phantoms (dolls made of materials whose electrical properties correspond to humans) is very often difficult to implement. Secondly, it is very difficult to eliminate other agents that could be responsible for initiating some diseases in humans in order to clearly isolate only the impact of nonionizing radiation.
In my opinion, the relevant study of the impact of the 5G radiation on the human body must have a multidisciplinary character and must necessarily include the following activities:
5G and COVID-19
Ban of 5G networks and impact on technological development
Personally, I do not like to use the adjective “harmful” or “dangerous” for any technology, because everything is a matter of correct use, and in case of exposure to radiation, the question of the dose is relevant… If we speak about the influence of electromagnetic fields on people then we can talk about field levels, i.e. electrical or magnetic fields strength, density of electromagnetic waves to which people are exposed and which can potentially generate certain biological effects. Clearly, we have to consider other significant parameters of non-ionizing radiation such as frequency, distance of source from the human body, position in relation to the source of radiation and, of course, time of exposure to radiation. So, let me simplify a bit; the question of harmfulness in general simply does not have an unambiguous answer, but it depends on a number of factors. For example, you can ask yourself if consuming alcohol or sunbathing on the beach is harmful. Of course it is, if an enormous quantity of alcoholic beverages is consumed in a short period of time or sun is consumed daily in the middle of the summer from 10 a.m. to 3 p.m. without protective cream. On the other hand, a glass of wine after a meal or sunbathing after 6 p.m. in the summer is unlikely to harm health.
Once again, the levels of fields and other relevant dosimetry sizes must be compared with the limit values prescribed by relevant domestic and international legislation.
In order to return to the initial question, I point out once again that a serious and systematic work of multidisciplinary teams is necessary to answer this question, but not only of a scientific-research character, but also of an indispensable and educational character in terms of lectures, organizing public meetings and panels, writing popular brochures, participating in radio and TV shows, writing texts for portals, all in terms of better informing which is rightfully sensitized for this issue, as is usually the case when new technology is introduced into the society.
- What types of electromagnetic radiation do we distinguish and can you briefly explain them?
Ionizing radiation contains sufficient amounts of energy to break atoms, that is, to break the chemical bonds and release electrons and create electrically charged particles – ions. Ionizing radiation, depending on the dose or degree of irradiation, may have a harmful effect on biological systems.
Ionizing and non-ionizing radiation is separated in the electromagnetic spectrum, and the delimitation of these two phenomena is at frequencies of approximately 1015Hz.
In short, regarding non-ionizing radiation, it can be said that low frequency fields due to large wavelengths do not have thermal effects on humans, that radio waves in higher parts of the spectrum, because their wavelengths are comparable to the body, penetrate the organism and warm up the tissue. High frequency fields in the 5G frequency range do not penetrate the body much, but they mostly remain on the body surface, so the power density absorbed on the body surface can be associated with local surface heating.
It is entirely up to biomedical scientists to connect the temperature increase on the surface of the body (due to absorbed strength) with possible consequences for human health.
- What kind of electromagnetic radiation do networks of mobile communications transmit?
- Does EM radiation of 5G mobile communications networks differ from those of previous generations (e.g. 4G, 3G, 2G) and what is their impact on the human organism and the environment?
On the other hand, at GHz frequencies, especially over 6 GHz, the depth of field penetration into tissues is low, so SAR is no longer an appropriate measure for determining the absorption of energy in the body. In this case, the absorbed power density of the electromagnetic field is much more appropriate as the dosimetry size. The correlation of the average absorbed power density (caused by the outer intrusion field) on the body surface with the surface temperature rises is the basis for guidelines in protecting people against the radiation of 5G generation devices.
So instead of warming tissue inside the body due to penetration of the electromagnetic wave, the radiation effect of the 5G system is local heating on the surface of the body.
The rigorous mathematical definitions of the absorbed power density on the body surface have been set up and the so-called thermal factors that local temperature rises on the body surface with the absorbed power density on the body surface are the main mission of the international IEEE working group, which has been working on it for a year now, and of which I am a member. Several official publications are being prepared, which will present the group's work in prestigious journals.
What are the differences in the work and EM radiation of modern wireless communications (e.g. Wi-Fi, Bluetooth, mobile communications)?
In the case of new 5G services, it is necessary to implement a large number of densely installed base stations operating in the area of millimeter waves (in the GHz frequency range), since the radiation of 5G systems is shorter in range. The consequence of an increased number of radiation sources is the accumulation effect in the absorption of electromagnetic energy, i.e. the additive effect on tissue heating (dominant effect of high frequency fields). On the other hand, the dosimetry of the incident field in previous mobile communication systems (2G/3G/4G) was carried out using relatively simple procedures, both experimental and computer dosimetry. Considering the exceptional complexity of the upcoming mobile communication 5G systems, it is clear that the sophistication of mathematical models will become an indispensable item considering that radiation sources are complex MIMO antenna systems whose radiation diagrams depend on the desired capacity and speed of data transmission, and are focused on the end user and, moreover, change with regard to the target user. This points to the inevitable fact that stochastic modelling of radiation sources in the form of 5G systems will become a necessary step in the assessment of realistic levels of incident fields to which human is potentially exposed.
Are there certain precautions and how to apply them?
Precautionary measures mainly consist of adherence to safety guidelines prescribing different types of restrictions, which can in principle be divided into limits on quantities generated in the body due to the impact of external fields and consequently restrictions on external fields. Finally, these measures, for each specific case, are reduced to a certain safety distance from the radiation source depending on the declared power of the antenna system and taking into account the relative position of the source in relation to the human, for example whether the human is in the direction of the maximum of the main beam of the radiation diagram.
Studies on the harmfulness and impact of 5G mobile communications networks
- Are there any studies on the effect of mobile communications radiation on the human organism so far?
The international body whose guidelines for the protection against non-ionizing radiation are followed by the majority of EU members is the International Commission on Non-Ionizing Radiation Protection (ICNIRP).
Guidelines prescribed by the ICNRP (ICNIRP Guidelines for Limiting Exposure to Electromagnetic Fields (100 kHz to 300 GHz)) published in March 2020, in summing up the findings available from recent biomedical literature regarding the assessment of harmfulness to the health of non-ionizing fields, say: the only documented adverse health effects caused by exposure to radio-frequency electromagnetic fields are nerve stimulation, the changes in cell membrane permeability and the effects of temperature increase.
It should be stressed that these are updated guidelines constituting the amended ICNIRP document of April 1998.
It should also be stressed that there are biomedical scientists who dispute the ICNIRP conclusions, usually arguing that it is necessary to take into account the non-thermal effects and long-term exposure to fields. As I have already pointed out, only biomedical scientists are relevant for some answers, and the multidisciplinary working groups are, in my opinion, necessary to answer a number of questions related to non-ionizing radiation.
Are there studies on the impact of 5G networks on human organisms and their harmfulness?
The issue of potential harmfulness of this type of radiation should be addressed to biomedical scientists. In principle, the existing dosimetry studies and protective guidelines in a way covered the entire part of the electromagnetic spectrum that is significant for non-ionizing fields, i.e. frequencies below 300GHz. However, it should be noted that in recent decades low frequency bands have been of particular interest related to the analysis of powerlines and transformer stations, and high frequencies, concerning the analysis of GSM and UMTS systems. In this regard, the above-mentioned SAR size was widely used in terms of the power averaged over mass and consequently local tissue heating. Since, at GSM frequencies wave penetrates into the organic matter, SAR is averaged over the control volume. On the other hand, since surface effects occur at 5G frequencies, instead of penetration into a biological object, SAR is no longer used in terms of the analysis of these phenomena, but the density of absorbed power. In particular, to protect humans from heat effects, local SAR is averaged on a volume of 10 g, while the latest thermal impact studies suggest the use of averaged area of 1 cm2 to 4 cm2 (depending on frequency range) for absorbed power density. Correlation of surface temperature rise with the average absorbed power density represents the basis for guidelines in protecting people from 5G radiation, i.e. for conducting appropriate biomedical studies. Overview and critical review of a number of recent studies related to potential field harmfulness in the GHz frequency range is available in the previously mentioned updated ICNIRP guidelines.
- What makes the study professionally and scientifically relevant?
There are really different studies. A large number is of a statistical-epidemiological character, which means that it is difficult to establish a causal link between exposure to fields of certain frequencies and possible health problems. In these studies there are several aggravating factors. First, it is not possible to perform experiments on live humans along with the development of theoretical models, and the extrapolation of experiments on animals or phantoms (dolls made of materials whose electrical properties correspond to humans) is very often difficult to implement. Secondly, it is very difficult to eliminate other agents that could be responsible for initiating some diseases in humans in order to clearly isolate only the impact of nonionizing radiation.
In my opinion, the relevant study of the impact of the 5G radiation on the human body must have a multidisciplinary character and must necessarily include the following activities:
- Internal dosimetry; part of the study relating to so-called multiphysics, encompassing electromagnetic and thermal modelling of the body.
- Dosimetry of the incident field; the engineering part of the study dealing with the calculation and measurement of external fields to which human is exposed.
- Biomedical aspects; part of the study relating to mechanisms for correlation mechanisms of external fields and the human body and consequential biological effects such as tissue heating, i.e. skin and eye surfaces in the case of 5G systems. At the very least, a serious overview of the relevant biomedical existing literature should be carried out if it is not possible to conduct own studies.
- Legislation - part of a study that discusses irradiation limits based on relevant national/international legislation. This aspect requires knowledge of laws, regulations and appropriate standards for the calculation and measurement of electromagnetic fields inside and outside the human body.
5G and COVID-19
- According to your knowledge, is there any connection between the use of 5G technology and the outbreak of COVID-19?
Ban of 5G networks and impact on technological development
- Do you think 5G technology should be banned and what are the possible consequences of such a ban?
Personally, I do not like to use the adjective “harmful” or “dangerous” for any technology, because everything is a matter of correct use, and in case of exposure to radiation, the question of the dose is relevant… If we speak about the influence of electromagnetic fields on people then we can talk about field levels, i.e. electrical or magnetic fields strength, density of electromagnetic waves to which people are exposed and which can potentially generate certain biological effects. Clearly, we have to consider other significant parameters of non-ionizing radiation such as frequency, distance of source from the human body, position in relation to the source of radiation and, of course, time of exposure to radiation. So, let me simplify a bit; the question of harmfulness in general simply does not have an unambiguous answer, but it depends on a number of factors. For example, you can ask yourself if consuming alcohol or sunbathing on the beach is harmful. Of course it is, if an enormous quantity of alcoholic beverages is consumed in a short period of time or sun is consumed daily in the middle of the summer from 10 a.m. to 3 p.m. without protective cream. On the other hand, a glass of wine after a meal or sunbathing after 6 p.m. in the summer is unlikely to harm health.
Once again, the levels of fields and other relevant dosimetry sizes must be compared with the limit values prescribed by relevant domestic and international legislation.
In order to return to the initial question, I point out once again that a serious and systematic work of multidisciplinary teams is necessary to answer this question, but not only of a scientific-research character, but also of an indispensable and educational character in terms of lectures, organizing public meetings and panels, writing popular brochures, participating in radio and TV shows, writing texts for portals, all in terms of better informing which is rightfully sensitized for this issue, as is usually the case when new technology is introduced into the society.