Using Mobile Phone Signal Quality to Estimate Exposure to Radio Waves: A Protocol and Pilot Study
One of the core goals of the ETAIN project is to evaluate the impact of radio-frequency electromagnetic fields (RF-EMF) on human health and the environment and explore viable options for reducing exposure. This research is being conducted by a team of researchers from several EU countries. One researcher, Nekane Sandoval, in collaboration with colleagues from the ETAIN project and Swiss TPH, has co-authored the article “Determining the relationship between mobile phone network signal strength and radiofrequency electromagnetic field exposure: protocol and pilot study to derive conversion functions.” The article presents an investigation into how mobile phones can be used to estimate exposure to RF-EMF from mobile wireless communication. As part of this study, the researchers developed an app called “5G Scientist,” which tracks signal quality on phones to potentially estimate RF-EMF exposure.
Objectives
The main goal of this research was to understand the relationship between signal quality and RF-EMF exposure from mobile phone use. By identifying this link, the researchers aimed to create a method to estimate exposure levels based on the signal quality values recorded by the 5G Scientist app.
Methodology
To achieve this objective, the researchers established a measurement protocol and conducted a pilot study. Data was collected in two countries, France and the Netherlands, across various locations using different phone models and network providers. The study tested different types of phone use, including voice and video calls, as well as data streaming (see Figure 1).
Measurement locations: Measurements were taken in both urban and rural areas within each country.
Equipment: Researchers used three smartphone models with the 5G Scientist app to record signal quality. RF-EMF exposure was assessed with an exposimeter (ExpoM-RF4) for far-field sources, such as cell towers, and with special probes to measure near-field sources, such as the phone itself during use.
Procedure: A trained researcher conducted simultaneous measurements with all tools, operating the phone in various ways to monitor both signal quality and RF-EMF exposure during typical use scenarios.
Results
The study observed a relationship between signal quality and RF-EMF exposure levels:
Ambient RF-EMF exposure: When signal quality was strong, RF-EMF exposure from cell towers was higher (see Figures 2 and 3), indicating that better signal quality often correlates with elevated ambient RF-EMF levels.
Exposure from the phone: When signal quality was weak, RF-EMF exposure from the phone itself increased, showing that the phone emits more radiation in low-signal quality areas.
Conclusions
The researchers concluded that the 5G Scientist app could be a valuable tool for estimating RF-EMF exposure from both cell towers and mobile phones. Given the widespread use of smartphones, the app could facilitate large-scale data collection on exposure levels, potentially enabling the development of exposure maps across Europe. This data would also support studies on the potential health effects of mobile phone use.
Figure 1. To validate the ETAIN 5G Scientist app (in blue), we gather data using a personal exposimeter (in orange) for ambient RF-EMF exposure and special probes (in pink) to measure RF-EMF emitted by the phone.
Figure 2. This figure shows that as signal quality improves (less negative values on x-axis), ambient RF-EMF exposure in the active band used by the mobile phone base station increases (higher values on y-axis). However, individual measurement points have substantial uncertainty.
Figure 3. This figure shows that when many measurements are collected from the same site, the correlation between exposure from the cell tower and average signal quality becomes strong. This means that with enough data from app users, we can create reliable exposure maps.
Figure 4. This figure shows that when mobile phone signal quality is low (more negative values on x-axis), the exposure near the ear increases (higher values on y-axis). This happens because the phone needs to use more power to maintain the connection and mobile services. Therefore, for mobile phone users, low environmental exposure does not reduce their personal exposure.
