Assessment of Electromagnetic Radiation Intensity from Smartphones in Video Communication Mode

Introduction. In the 2020s, the issue of participants' exposure to electromagnetic radiation during video conferencing (VC) has become increasingly important. The widespread use of these services is primarily due to coronavirus pandemic‑related self‑isolation. Other reasons include the mobility of students and employees, the proliferation of remote and hybrid work arrangements, and lower prices for mobile devices with video capabilities. This transformation can be demonstrated through the following example. Prior to the pandemic, a well-known free solution existed. During the time of self-isolation, six new products with similar functionality were added to the market. Later, two more appeared [1].

Since 2019, hardware and software terminals, server systems, cloud services, and smartphone applications have been used to make video communication more accessible. Yandex Telemost, VK Calls, MTS Link, and Max are the leaders in the Russian segment of online communication.

Non-ionizing electromagnetic radio waves that occur during VC can cause local heating of tissues. The question of how harmful this is requires comprehensive research. The authors of this article found out, that publicly available publications did not consider the massive use of video content on mobile devices, which led to the hypothesis that electromagnetic radiation (EMR) from smartphones is amplified in modern VC scenarios. Considering this, it is advisable to investigate the effect of Wi-Fi on the EMR values, as this particular issue has not been addressed in the literature. However, there are studies that assess the effects of mobile phones on the human body during conversation, that is, when using the device for its intended purpose. Nikitina V.N. and Vtornikova N.I. note the increased thermal effect of electromagnetic radiation, which is unfavorable for humans [2]. First of all, the adverse effect affects the brain [3], visual and auditory analyzers, and the thyroid gland [4]. According to some reports, direct contact of a mobile phone with a person's head causes a risk of long-term consequences and increases the likelihood of brain tumors [5], Alzheimer's disease, and early dementia [6].

Khorseva N.I. [7] notes fatigue, significant deterioration in performance indicators, sensorimotor reactions, fatigue, and cognitive functions in children and adolescents due to the use of mobile communication devices. Belpomme D. and Rakhmanin Yu.A. prove that mobile phones are the cause of changes in neurodevelopment and neurobiological behavior [8], as well as memory disorders, learning difficulties, attention problems, and behavioral issues in children [9].

Direct contact of the device with the human head clearly explains the identified negative effects on the nervous system and analyzers. However, there are other, non-obvious dependencies that require further study. Thus, the use of mobile phones for more than four hours per day affects the reproductive performance of both men [10] and women [11].

Thus, it can be argued that researchers' attention has been focused on studying the risks associated with using a mobile phone while talking without headphones, with the device in contact or near contact with the head. However, the situation where the user is engaged in video conferencing has not been considered, and the EMR has not been determined for such cases. As part of this study, we have attempted to address this gap by conducting a survey for the first time and subsequently proposing safety recommendations. To our knowledge, no similar surveys have been conducted before. The aim of this research is to determine the level of electromagnetic radiation emitted by smartphones during video communication sessions over the mobile internet and Wi-Fi networks.

To achieve this goal, we have set the following tasks:

— determination of the maximum and average values of electromagnetic radiation (energy flux density, EFD) at a distance of 0 cm and 15 cm from the top and bottom speakers of two devices (smartphones) during video calls;

— assessment of the impact of Wi-Fi usage on the EMR value;

— identification of points with the highest electromagnetic radiation levels in smartphones.

Materials and Methods. The level of electromagnetic radiation emitted by smartphones was measured using a PZ-41 device, which included three antenna converters: AC-1, AC-2, and AC-3. High-frequency electromagnetic field was converted into a constant voltage that was then applied to a measuring device. This device processed information and displayed the parameters of the electromagnetic field on a screen. The manufacturer of this device is Special Design Bureau PiTON, located in Nizhny Novgorod.

It should be noted that Russian mobile operators operate in subscriber ranges from 790 MHz to 2700 MHz. 4G (LTE) mobile data transmission standards use a frequency of 2600 MHz [12]. When using Wi-Fi technology, the operating frequency is 5150–5850 MHz.

Figure 1 illustrates the operation of the PZ-41 device for evaluating the EFD at frequencies of 2450 MHz and 5150 MHZ, measuring both maximum and average values during a 1-minute exposure.

EFD was measured at the Fire Safety Department of Civil Defense Academy of the Ministry of Emergency Situations of Russia on a laboratory bench simulating a work surface with a scale-coordinate paper attached. The smartphone was attached to a dielectric tripod in an upright position (MG 4.3.2501–09¹), and the measuring device with an antenna was attached to a special holder. The antenna of the PZ-41 was located at a distance of 0 and 15 cm from top and bottom speakers of the smartphone (Fig. 2).

Two mobile devices of different telecom operators, of the same year of manufacture, were tested. Each of them was in operation for 2.5 years.

Specifications of device No. 1:

— iOS operating system (iPhone 14 Рro);

— iOS version — 26.3.1(a);

— device memory capacity — 128 GB;

— telecom operator — Tele2.

Specifications of device No. 2:

— Android operating system (Samsung Galaxy A35 5G);

— version — Android 14;

— device memory capacity — 128 GB;

— telecom operator — MTS.

Smartphones were tested:

— without enabling Bluetooth and NFC modules (always);

— with the Wi-Fi module running (mentioned separately) and with Wi-Fi disabled.

The video was transmitted using the Yandex Telemost service. The product of the Russian company, Yandex, has been operating on iOS and Android platforms since the summer of 2020.

To create a permanent live video conference, a training video with sound was played on tablet (device 3). The content was transmitted from smartphone 1 to smartphone 2 using the internet. Devices 1 and 2 were located in different rooms. During the experiment, we simulated the interference of people moving around and making gestures near the phone. Such cases were marked with * in the table. Data received through a poor internet connection was marked with #.

When using Wi-Fi, the distance from the router was not more than 10 meters, taking into account the obstacle in the form of a reinforced concrete wall.

We considered the hypothesis of increased EMR during smartphone operation in video communication mode. To assess its validity, we measured the EMR of devices in call mode without turning off Wi-Fi.

There were small EFD values in the talk mode, especially at a distance of 15 cm. The data collected was important for comparing EFD results with video call mode.

Research Results. Tables 1–4 show the results of measurements of EFD_max and EFD_avg in video call mode at two control points — at a distance of 0 cm and 15 cm from the top and bottom speakers of smartphones at a frequency of 2450 MHz. The tables present five EMR values according to the order of measurements. Measurements 1–5 were conducted on the same day and in the same order.

Table 5 summarizes the average values for the five measurements presented in Tables 1–4, as well as the difference between the EFD values recorded for iOS smartphones and Android. This difference was defined as the quotient of dividing a larger value by a smaller one. It is important to note that the iOS indicator was found to be higher in almost all experiments compared to that of Android.

The results support the hypothesis that there is an increase in electromagnetic radiation during video calls on a smartphone. This research fills a gap in our knowledge in this area. It opens up the possibility for further studies to explore and understand more about EMR radiation while using smartphones for video conferencing, online gaming, virtual and augmented reality, etc.

An important finding of the study is a significant reduction in electromagnetic radiation when using Wi-Fi technology for video communication on a smartphone. This can be attributed to the characteristics of communication via Wi-Fi, as the short range of the router means that the smartphone does not require a powerful transmitter.

Conclusion. The principle of “protection by distance” has been experimentally confirmed: when you move away from a smartphone by 15 centimeters, electromagnetic radiation decreases. This means that there is a safe way to make video calls. We recommend using gadget holders to create distance between the person and the device. Do not wear the device on your body or lean against it during a video call, and make sure to remove it at least 15 centimeters from your body.

For different models of mobile devices, high EMR values were found at different points, which could be explained by the design features of smartphones. For an iOS device, the bottom speaker was found to have high values, while the top speaker was found to have high values on the Android platform. Users should study the design of the device to form their own safety rules. Further research is needed to build the EMP fields of personal mobile communication systems.

It has been proven that, due to the characteristics of the transmitter, a failure in the internet connection can lead to an increase in energy flux density. This should be communicated to users.

The results obtained are of practical importance and offer promising prospects for future research. They may include:

— construction of fields of spatial distribution of the energy flux density from a smartphone in video communication mode,

— conducting similar measurements with other smartphone models,

— development of recommendations for safe operation,

— introduction of EMR norms during remote communication using smartphones.