Measurements of Radio-Frequency Electromagnetic Field Levels in EXPO2025 Osaka, Kansai, Japan.

In this study, we investigated radio‑frequency electromagnetic field (RF‑EMF) levels at the Expo 2025 Osaka, Kansai, Japan, a large‑scale international event that attracted approximately 26 million visitors during the event period. Spot and portable measurements were conducted for broadcast, 4G, 5G, and ISM bands in both indoor and outdoor environments. The observed E‑field strengths remained below the reference levels specified in the Japanese Radio Radiation Protection Guidelines, with the maximum E-field strength corresponding to 0.4% of the guideline limits. The RF‑EMF levels measured at the venue were comparable to those measured in typical urban areas and consistent with findings from similar studies conducted overseas. These results confirm that the level of RF‑EMF exposure during high‑density public events in Japan remains below regulatory limits and exhibits behavior trends similar to those observed in ordinary urban environments.