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A STUDY OF ENVIRONMENTAL ELECTROMAGNETIC RADIATION LEVELS

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John C. H. Wang · 1977

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This 1977 study documented baseline environmental RF radiation levels that were likely far lower than today's wireless-saturated environment.

Plain English Summary

Summary written for general audiences

This 1977 technical report by Wang examined environmental electromagnetic radiation levels from broadcast transmitters, measuring power density and field strength in real-world settings. The study focused on assessing potential radiation hazards and biological effects from RF emissions in the environment. This represents early systematic documentation of EMF exposure levels that people encounter from broadcasting infrastructure.

Why This Matters

This 1977 study represents a pivotal moment in EMF research when scientists first began systematically measuring the electromagnetic radiation we encounter daily from broadcast transmitters. At a time when FM radio and television broadcasting were rapidly expanding, Wang's work provided crucial baseline data on environmental RF exposure levels that regulatory agencies still reference today.

What makes this research particularly significant is its focus on real-world exposure scenarios rather than laboratory conditions. The power density and field strength measurements from broadcast transmitters documented in this study likely captured radiation levels that were orders of magnitude lower than what we experience today from cell towers, WiFi networks, and personal wireless devices. This historical perspective shows how dramatically our electromagnetic environment has intensified over the past five decades.

Figures from the Original Paper

Diagrams extracted from the original research document.

graphPage 4 - AI-described figure: Figure 1: Calculated Field Strength vs. Distance in the Vicinity of a Standard AM Broadcasting Antenna
p. 4 of the original PDF
graphPage 5 - Figure 2: A Comparison of Calculated and Measured Field Strengths in the Vicinity of a Standard AM Broadcasting Antenna (WTOP, Wheaton, MD, 1500 kHz, 50 kW)
p. 5 of the original PDF
graphPage 7 - Figure 3: Calculated Power Density vs. Distance for 3 Different Power Levels Used in FM Broadcasting
p. 7 of the original PDF
graphPage 9 - Figure 4: Calculated Power Density vs. Distance for 4 Different Power Levels Used in TV Broadcasting
p. 9 of the original PDF

Exposure Information

A logarithmic frequency spectrum from 10 Hz to 100 GHz showing where this study's 535-1605 kHz exposure sits relative to common EMF sources.Where This Frequency Sits on the EMF SpectrumELFVLFLF / MFHF / VHFUHFSHFmm10 Hz100 GHzThis study: 535-1605 kHzPower lines50/60 HzCell phones~1 GHzWiFi2.4 GHz5G mm28 GHzLogarithmic scale

Specific exposure levels were not quantified in this study.

Study Details

The purpose of this technical memorandum is to summarize some FCC work in evaluation of environmental electromagnetic radiation levels in selected cases and to serve as a contribution to the continuing comprehensive study of the electromagnetic environment.

Calculations and measurement data are presented. The study includes systematic investigation of biol...

Field strength calculations and measurements are presented for standard broadcast transmitters, FM t...

Exposure of the general public appears to be relatively low. Current safety standards in the U.S. are based on power densities of 10 mW/cm² and 1 mW/cm² for short-term and long-term exposures, respectively. Exposure from even the most powerful television station is several orders of magnitude less than these levels. Biological effects have been observed at levels below 10 mW/cm², but these findings must be viewed in perspective and subjected to systematic review before meaningful interpretation can be drawn.

Cite This Study
John C. H. Wang (1977). A STUDY OF ENVIRONMENTAL ELECTROMAGNETIC RADIATION LEVELS.
Show BibTeX
@article{a_study_of_environmental_electromagnetic_radiation_levels_g6436,
  author = {John C. H. Wang},
  title = {A STUDY OF ENVIRONMENTAL ELECTROMAGNETIC RADIATION LEVELS},
  year = {1977},
  
  
}
No DOI on file for this study.

Quick Questions About This Study

The specific power density and field strength measurements aren't available in the abstract, but this study documented environmental RF levels from FM radio and TV broadcast transmitters during an era when wireless technology was far less prevalent than today.
Environmental RF radiation has increased dramatically since 1977 due to cell towers, WiFi networks, and billions of wireless devices. The broadcast transmitter levels Wang measured likely represent a fraction of current environmental exposure.
As FM radio and television broadcasting expanded rapidly in the 1970s, researchers like Wang began systematically documenting baseline environmental radiation levels to assess potential health risks and establish exposure standards for the growing broadcast infrastructure.
The study examined potential biological effects and radiation hazards from broadcast transmitters, though specific findings aren't available. This research helped establish early understanding of RF exposure risks from broadcasting infrastructure before modern wireless technology emerged.
Studies like Wang's provided foundational data that regulatory agencies used to establish RF exposure limits. However, these standards were based on much lower environmental radiation levels than what exists today with ubiquitous wireless technology.