How 5G networks are reshaping our exposure to mobile phone radiation

Rural cell phone users face higher radiation levels despite fewer cell towers, study finds

BARCELONA — When it comes to mobile phone radiation, living in a city with abundant cell towers might actually reduce your exposure. This seemingly paradoxical conclusion emerges from new research examining how 5G technology is changing our electromagnetic environment across urban and rural landscapes.

Switzerland, an early adopter of 5G technology in Europe, provided an ideal testing ground for this research. After introducing new frequency bands in 2019, including the crucial 3.5 GHz band used by 5G networks, the country became perfectly positioned to study how these advanced networks influence our daily exposure to electromagnetic fields.

Modern 5G networks employ sophisticated antenna systems that function quite differently from previous cellular technologies. These systems, called massive Multiple-Input Multiple-Output (Ma-MIMO) antennas, can direct focused beams of signal precisely toward users’ devices. Consider it like a spotlight following an actor on stage rather than flooding the entire theater with light. This targeted approach, known as beamforming, marks a significant shift from older cellular networks that broadcast signals more uniformly across wide areas.

The research team, part of Project GOLIAT, collected measurements across two major Swiss cities (Zurich and Basel) and three rural villages (Hergiswil, Willisau, and Dagmersellen). In their baseline measurements, taken with phones in airplane mode, they found that exposure levels increased with population density. Rural villages experienced average exposure levels of 0.17 milliwatts per square meter (mW/m²), while the cities of Basel and Zurich recorded higher averages of 0.33 and 0.48 mW/m² respectively.

“The highest levels were found in urban business areas and public transport, which were still more than a hundred times below the international guideline values,” says study senior author Martin Röösli, a researcher at the Swiss Tropical and Public Health Institute, in a statement.

When researchers simulated intensive data usage by downloading large files repeatedly, exposure levels increased significantly to averages of 6-7 mW/m². This increase was particularly noticeable in urban areas, where 5G networks use beamforming to direct stronger signals to active devices.

The most compelling findings emerged during tests of maximum upload speeds, where devices continuously sent large files to the network. During these tests, exposure levels reached an average of 16 mW/m² in cities but jumped to 29 mW/m² in villages. This unexpected result occurs because phones in rural areas must work harder to maintain connections with distant cell towers.

“We have to keep in mind that in our study the phone was about 30 cm away from the measuring device, which means that our results might underestimate the real exposure,” says study lead author Adriana Fernandes Veludo. “A mobile phone user will hold the phone closer to the body and thus the exposure to RF-EMF could be up to 10 times higher.”

“Environmental exposure is lower when base station density is low. However, in such a situation, the emission from mobile phones is by orders of magnitude higher,” This creates what Veludo describes as a paradoxical situation. “This has the paradoxical consequence that a typical mobile phone user is more exposed to RF-EMF in areas with low base station density.”

As this research expands beyond Switzerland’s borders to nine more European nations, scientists will track how different approaches to 5G implementation affect electromagnetic exposure levels. Their findings will help inform the ongoing debate about optimal cellular network design and its implications for public health.