Personal Radio Frequency Electromagnetic Field Exposure Among Swiss Adolescents in the 5G Era

Introduction The rapid expansion of wireless technologies, including 5G, has introduced complex radiofrequency electromagnetic field (RF-EMF) exposure patterns, yet real-world data on personal exposure in adolescents remain limited. This study, conducted within the HERMES3 (Health Effects Related to Mobile Phone Use in Adolescents) cohort, aims to characterize personal RF-EMF exposure among Swiss adolescents. Methods A subsample of 143 adolescents participated in a personal measurement study between June 2023 and January 2025. Participants carried a personal exposimeter (ExpoM-RF4) for ca. 72-hours, to collect Geographic Positioning System coordinates and exposure data from 35 frequency bands. During this period, participants were asked to fill-out an electronic activity diary. Following data quality control, frequency bands were categorized by source and analyzed descriptively. Results Mean and median daily total RF-EMF levels of 0.09 mW/m 2 and 0.06 mW/m 2 , respectively, were measured. WiFi/Bluetooth contributed most to total exposure (35 %), followed by broadcast (31 %), uplink (19 %), downlink (10 %), time division duplex (4 %), and Digital Enhanced Cordless Telecommunications (0.7 %). Across environments, average RF-EMF exposure was highest in transport systems (0.47 mW/m 2 ) and lowest at school (0.08 mW/m 2 ) and home (0.07 mW/m 2 ). Conclusion Despite widespread 5G deployment, overall personal exposure among adolescents remains similar to pre-5G levels, with variations mainly reflecting user behavior and network density. However, this should not be interpreted as a direct causal estimate of the independent effect of 5G deployment. WiFi/Bluetooth was the main contributor to daily personal exposure. Personal measurements underestimate exposure contributions from sources emitting close to body.