COST INTERACT CA20120 podcast - Episode 2 - Dr. Conchi Garcia Pardo

Well, thank you, Adrian, for the invitation to be on the second issue of the podcast of the action. Thank you all for inviting me to talk about this hot topic nowadays. I hope this conversation will shed light on the subject and help to solve doubts, especially for the general public.

Sure. Very basically, an electromagnetic wave is an oscillatory electric and magnetic field at the same time. Let me show you one picture to illustrate better. As I was saying, an electromagnetic field is an oscillatory electric field, this is the blue curve, which due to its oscillatory nature creates an oscillatory magnetic field, which is the red one. An oscillatory magnetic field at the same time originates an oscillatory electric field, so this continued process creates an oscillatory electromagnetic wave which propagates in a direction perpendicular to the oscillation of both fields. The rate at which this field changes with time is the frequency, which is also related to the wavelength. Depending on frequency or wavelength, in terms of safety they are the same, but when frequency increases, wavelength decreases, and when frequency decreases, wavelength increases. Taking this into account, we can look at this picture in which I have a recap of how electromagnetic waves can be classified. For low frequencies we have what we call radio waves, and on the opposite side for very high frequencies we have gamma rays. This is a simple classification but very illustrative. Electromagnetic waves interact with the human body in different ways, but the main classification is non-ionizing, when the wave has the capability to change the structure of human cells, and ionizing, meaning the wave has the capability to change the cellular structure of the body. Looking at this picture, radio waves and microwaves, which are on the lower part of the radio electric spectrum, are non-ionizing waves, while X-rays and gamma rays are ionizing waves. X-rays and gamma rays are used for medical purposes, not for communications. For cellular networks, the main phenomenon is non-ionizing. Even higher in frequency we have visible light, which is at higher frequency compared to microwaves used by Wi-Fi, AM or FM radio, and mobile communications. So we can be on the safe side because these are non-ionizing.

Yes, when focusing on radio and microwaves, the main effect found so far in literature and scientific studies is thermal heating. For the time being, no further effect has been found by experts.

Let me talk first about who establishes the restrictions and limits, and who regulates how to measure and evaluate exposure. There is an international organism called ICNIRP, the International Commission on Non-Ionizing Radiation Protection, which is a non-profit organization linked to the World Health Organization. ICNIRP regularly reviews the scientific evidence about the effect of electromagnetic fields on health, focusing on non-ionizing waves. However, ICNIRP is not a regulatory organism; it is an advisory international supranational advisor. It provides guidelines for the assessment and assurance of safety of EMF exposure. Every country is free to adopt the ICNIRP guidelines or not. Most countries do. For example, in the European Union this is not regulated by the European Commission; it is harmonized by country. Italy has different regulation compared to Spain. So it is up to the countries to establish limits according to what international organisms say and according to their own analysis. In general, there are small differences, but the most hot topic today is how to measure and evaluate exposure from mobile base stations. For this, we have different kinds of meters for evaluating the electric field or the power density. This device on the left is a spectrum analyzer which can measure in selected frequency to evaluate different base station radiation classified by service and frequency. On the right is a 3D probe which captures the entire spectrum. On the other hand, we have wideband meters that do not distinguish between technology or base station. In both cases, it is key that the personnel using these meters know how to select and configure the devices and interpret the results, because measuring the electric field is not that complicated, but it requires expertise to know what the number means.

I think EMF exposure is an engineering area but also has a health impact, so cooperation is key. I would like to remind that our work as engineers is not focused on determining if electromagnetic waves are healthy or not; that is covered by physicians who are experts in health and the human body. Physicians evaluate how electromagnetic fields affect health and up to which level they can start affecting people. In a second stage, engineers evaluate and determine if in a certain scenario with a certain configuration, the requirements established by health experts are met. So there are two phases highly connected. Another important thing is that when talking about health analysis and studies, science is not exactly as we understand it in engineering. In engineering, we are more familiar with research on algorithms, protocols, and measurement methodologies, which are usually established and proven. In medical research, it is different because you are researching with people, based on statistical observation. The scientific evidence means that a study should have enough evidence. For example, a physician's opinion on one case is not the same as a meta-analysis or systematic review that involves a large set of people over a long time, analyzing and separating the influence of different factors. We have to take care when reading health research and understand the level of scientific evidence.

Yes, as you said, I am co-leading along with Professor Luis Correa the group of EMF at interact. The main goal of our group, and all groups in interact, is to exchange research and outcomes on a particular topic, in this case EMF exposure. The objective is to foster joint collaborations and joint research on the topic to improve the quality of research through collaboration between experts. During meetings, we present results of our research and discuss from a technical perspective, and also plan joint activities, research, or dissemination. In the EMF group, we have identified a list of open challenges related to EMF exposure. Some examples are how to measure exposure in 5G, how to refine or improve measurement methodology for 5G, especially at higher frequencies or with beamforming, and how to improve estimation of joint exposure at a certain location when using several technologies at the same time. The goal of the working group is to have some outcomes in these open challenges by the end of the action, if possible through joint work and collaborations.

Well, thank you, Adrian, for your time, and thank you to the people listening. I hope I have helped clarify some critical issues today. I invite all people interested in the topic to join us, join interact, and join us in the following meetings of the EMF working group. Thank you again. See you soon, everybody.