A validation study in Environmental Research tested whether the ETAIN 5G Scientist app, built by an EU-funded project on electromagnetic fields and planetary health, can turn measurements from ordinary smartphones into reliable maps of radiofrequency exposure from mobile networks. Researchers walked routes in Utrecht and Basel with both the app and a reference exposimeter and compared the two.
Agreement was strong for 4G in both cities and for combined 4G and 5G estimates in Utrecht, but only moderate in Basel, where 5G was detected in nearly half the grid cells. The authors conclude that the app can produce validated exposure maps at scale. This study tests the finished maps; another article from the same team examines the step before, how closely the app's raw signal readings track frequency-selective exposure.
Quotes
"The ETAIN 5G Scientist app, developed within the ETAIN (Exposure To electromAgnetic fIelds and plaNetary health) project uses citizen science smartphone data to produce calibrated RF-EMF exposure maps for 4G/5G networks at 25 × 25 m2 spatial resolution across Europe. As of 2026, the app had collected over 19 million measurements globally."
"4G LTE exposure estimates correlated strongly with measured exposure in both Utrecht (rs = 0.87, 95% CI: 0.80-0.91, N = 127) and Basel (rs = 0.71, 95% CI: 0.63-0.78, N = 214; both p < 0.001)."
"The combined 4G LTE and 5G NR exposure estimates correlated strongly in Utrecht (rs = 0.88, 95% CI: 0.81-0.92; 19.7% of grid cells with 5G NR detection) but showed moderate correlation in Basel (rs = 0.41, 95% CI: 0.29-0.53; 45.3% of grid cells with 5G NR detection)."
"Sensitivity analyses showed map reliability stabilised at five or more observations per grid cell and improved when data from at least two network operators were combined."
"These results demonstrate that the ETAIN 5G Scientist application can produce validated, spatially continuous RF-EMF exposure maps at scale. The approach is well suited for characterising exposure trends as mobile networks continue to evolve."
Location
📍 Netherlands, Switzerland
📍 Utrecht
📍 Basel
Citizen science-based mapping of radiofrequency electromagnetic field exposure in Europe: A proof-of-concept validation study
Baruah et al. (2026) Environmental Research Journal Level 2ⓘ
