Swedish Public Railway Transportation Environments May Be Associated With High Exposure to Radiofrequency Electromagnetic Field (RF-EMF) Radiation

BackgroundThe increasing use of wireless communication technologies has substantially changed the radiofrequency electromagnetic field (RF-EMF) environment.Public transportation systems represent complex RF-EMF exposure environments, but there is limited information regarding maximum environmental RF-EMF levels during routine travel across different transportation settings. ObjectivesThis study aimed to characterize maximum environmental RF-EMF power density in Swedish transportation environments, including the Arlanda Express, Stockholm Central Railway Station, the Stockholm subway system, and intercity railway travel between Stockholm and Örebro. MethodsBroadband RF-EMF measurements were performed using a Safe and Sound Pro II exposimeter for at least 2 minutes at each measured point. ResultsRF-EMF exposure showed substantial spatial and temporal variability across all investigated environments.The highest maximum power densities were consistently recorded at Stockholm Central Railway Station, where repeated measurements at ground level exceeded the instrument's upper measurement limit (>2,500,000 µW/m²).Subway measurements showed considerable variability, with localized maximum values exceeding 200,000 µW/m².Lower levels were generally observed during railway travel between stations, although high RF-EMF power density occurred on some railway sections.Exposure levels during travel varied according to location, network conditions, and transportation environment. ConclusionsPublic transportation environments, particularly major railway stations, can represent locations with high maximum power density levels.The measured levels were below current exposure limits recommended by the Federal Communications Commission (FCC) and International Commission on Non-Ionizing Radiation Protection (ICNIRP), which are based on protection against established thermal effects and do not incorporate non-thermal biological effects.However, the measured levels substantially exceeded the precautionary exposure levels recommended in the EUROPAEM EMF guideline 2016 for Wi-Fi exposure during daytime of 10 µW/m 2 , for nighttime 1 µW/m 2 , and for sensitive persons 0.1 µW/m 2 to protect against non-thermal effects.Future studies combining broadband measurements, frequency-selective analyses, and personal dosimetry are needed to better characterize individual exposure during modern daily travel.