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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 FCC study documented baseline environmental EMF levels before the wireless revolution transformed our electromagnetic landscape.

Plain English Summary

Summary written for general audiences

This 1977 FCC technical report studied environmental electromagnetic radiation levels from broadcast transmitters, measuring field strength and power density across different locations. The research was part of early efforts to document baseline EMF exposure levels in communities near radio and television broadcasting facilities. This work helped establish measurement protocols that would inform later EMF exposure guidelines.

Why This Matters

This 1977 FCC study represents a critical piece of early EMF exposure documentation, conducted during an era when broadcast transmitters were the dominant source of environmental radiofrequency radiation. What makes this research particularly significant is its timing - it captured baseline exposure levels before the explosion of wireless technologies that would dramatically increase our daily EMF exposure. The reality is that environmental radiation levels measured in 1977 were likely orders of magnitude lower than what we experience today from cell towers, WiFi networks, and countless wireless devices.

The science demonstrates that understanding historical exposure baselines is crucial for assessing how dramatically our electromagnetic environment has changed. While this study focused on broadcast transmitters, today's cumulative exposure from multiple sources creates a fundamentally different radiation landscape than what existed when this research was conducted.

Figures from the Original Paper

Diagrams extracted from the original research document.

graphPage 4 - Figure 1: Calculated Field Strength vs. Distance in the Vicinity of a Standard AM Broadcasting Antenna
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)
graphPage 7 - Figure 3: Calculated Power Density vs. Distance for 3 Different Power Levels Used in FM Broadcasting
graphPage 9 - Figure 4: Calculated Power Density vs. Distance for 4 Different Power Levels Used in TV Broadcasting

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. The objectives of this program are to determine what effects electromagnetic radiation has on living organisms under different conditions of exposure, to assess the potential hazards with reference to realistic exposure environments, and to establish a sound scientific basis for appropriate remedial and/or control measures which appear warranted.

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

Field strength calculations vs. distance for different radiated power levels are shown for AM broadc...

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

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_g5663,
  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 study measured field strength and power density levels from broadcast transmitters in various environmental locations. This included documenting electromagnetic radiation exposure from radio and television broadcasting facilities across different community settings.
This research captured baseline environmental EMF levels before cell phones, WiFi, and modern wireless technologies existed. It provides crucial historical context showing how dramatically our electromagnetic environment has changed over the past 45 years.
ERMAC (Electromagnetic Radiation Management Advisory Council) was involved in this early FCC effort to systematically document environmental electromagnetic radiation levels. The council helped establish measurement protocols for assessing broadcast transmitter exposure in communities.
Environmental radiation levels in 1977 were likely orders of magnitude lower than current exposure from multiple wireless sources. Today's cumulative EMF exposure from cell towers, WiFi, smartphones, and IoT devices creates a fundamentally different electromagnetic landscape.
The study helped establish standardized protocols for measuring field strength and power density from broadcast sources. These early measurement techniques became foundational for later EMF exposure assessment methods and regulatory guidelines still used today.