Measurement of personal radio frequency exposure in Japan: The Hokkaido Study on the Environment and Children's health

Abstract

Overview

The study investigates the increasing exposure of Japanese children to radiofrequency electromagnetic fields (RF-EMF), using a personal exposure meter (ExpoM-RF) and documenting various environmental and usage factors influencing this exposure. A group of 101 children, aged between 10-15 years and part of the prospective birth cohort "Hokkaido study," participated in this study.

Findings

• Exposure to RF-EMF was systematically recorded across a spectrum of 700 MHz to 5.8 GHz over three days.
• Exposure sources included mobile phone base stations, mobile phones, Wireless LAN, digital TV, and other specific frequency bands (2.5 GHz and 3.5 GHz TDD, 1.9 GHz TDD).
• Most significant exposure contributors were the downlink from mobile phone base stations.
• Urban residency and various usage patterns like video viewing and text messaging correlated with higher exposure levels.
• A notable association was found between higher nighttime Wireless LAN exposure and the inattention/hyperactivity subscale of the Strengths and Difficulties Questionnaire (SDQ), suggesting an indirect link to hyperactivity and internet usage behaviors.

Conclusion

The study provides essential insights into the personal RF-EMF exposure among children in Japan, indicating lower exposure rates compared to European data but significant contributions from specific sources and usage patterns. It highlights the need for further detailed studies to explore the intricate factors influencing RF-EMF exposure in children, specifically considering the possible health risks associated with high and prolonged exposure.