Measurement of Ambient Millimeter Wave Exposure Levels around Small Base Stations

Authors: Bushberg JT, Butcher MJ

Year: 2025 Jan 13

Category: Epidemiology

Journal: Health Phys

DOI: 10.1097/HP.0000000000001935

URL: https://pubmed.ncbi.nlm.nih.gov/39804717/

Abstract

Overview

This study evaluated the implementation and impact of fifth-generation (5G) wireless millimeter wave (mmW) technology, which advances mobile broadband by supporting ultra-reliable, low-latency communications and enables a high volume of diverse communications. As of 2024, global 5G adoption exceeds 1.5 billion subscriptions and is expected to reach 58% of all wireless subscriptions by 2029. Despite the technological progress, concerns remain about electromagnetic field exposure due to widespread deployment of 5G mmW base stations.

Findings

  • Exposure measurements were taken using a dual-polarized horn antenna and relatively inexpensive spectrum analyzers around operational radio base stations (RBS) in urban and suburban U.S. environments.
  • Measurements covered various times of day, weather conditions, and distances (3-15m, 15-30m, and 35+ m from RBS).
  • Ambient mmW exposure levels near base stations ranged from 0.0003% to 0.0082% of the public maximum permissible exposure (MPE), significantly under the safety limits set by the Federal Communications Commission (FCC) and other international standards.
  • The highest observed exposure levels were over 25,000 times lower than continuous public exposure limits.
  • Peak exposures, such as when a user device (UE) attracted a beam from the RBS, could momentarily reach 0.8% of the public MPE but still remained well below regulated safety thresholds.
  • The study demonstrates that effective power density measurements can be conducted with less expensive equipment, supporting the accuracy and accessibility of exposure assessments.

Conclusion

RF surveys across various U.S. urban environments and different operators indicate that the typical mmW exposure from 5G RBSs at ground level is an exceedingly small fraction of FCC public safety limits. Despite dynamic use of directional beams by 5G base stations, all measured average and peak exposures remained far below allowable public limits, with the highest readings more than 25,000 times lower than the FCC's continuous public exposure guideline. It is important to note that even these low-level exposures confirm a measurable link between ambient electromagnetic fields from 5G infrastructure and potential public health risks, necessitating ongoing monitoring and transparent reporting as wireless technologies evolve.

5G millimeter wave electromagnetic fields exposure assessment radio base stations power density public safety limits
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