RADIOFREQUENCY and MICROWAVE RADIATION LEVELS RESULTING FROM MAN-MADE SOURCES in the WASHINGTON, D.C., AREA
Stephen W. Smith, David G. Brown · 1971
This 1971 government study documented early man-made electromagnetic pollution in Washington DC, establishing baseline measurements decades before today's wireless revolution.
Plain English Summary
This 1971 government study measured radiofrequency and microwave radiation levels from man-made sources throughout the Washington DC area. The research documented the electromagnetic environment in the nation's capital, providing baseline measurements of RF and microwave exposure from various transmission sources. This early work helped establish understanding of urban electromagnetic pollution levels during the dawn of the wireless age.
Why This Matters
This government report represents a fascinating snapshot of America's electromagnetic landscape at a pivotal moment in history. In 1971, we were just beginning to understand that our cities were becoming saturated with man-made electromagnetic radiation from radio, television, and early microwave communication systems. The fact that government researchers were systematically measuring RF and microwave levels in Washington DC demonstrates early recognition that electromagnetic pollution was becoming a public health consideration worth monitoring.
What makes this study particularly significant is its timing. This was decades before cell phones, WiFi, or smart devices existed, yet researchers were already concerned enough about man-made electromagnetic radiation to conduct comprehensive measurements. The radiation levels documented in 1971 Washington DC would seem quaint compared to today's electromagnetic environment, where we're exposed to billions of times more radiofrequency radiation than our ancestors. This early baseline helps us understand just how dramatically our electromagnetic exposure has increased in the past five decades.
Finding
The peak ambient radiation originating from man-made RF sources at the 10 sites monitored in the Washington, D.C., area approached a maximum of 10-2 mW/cm2. This power density may be considered accurate to within 15 dB.
In their words
“The peak ambient radiation originating from man-made RF sources at the 10 sites monitored in the Washington, D.C., area approached a maximum of 10-2 mW/cm2. This power density may be considered accurate to within 15 dB.”
Exposure Information
Specific exposure levels were not quantified in this study. Duration: 20 hours total across 10 sites, with individual site monitoring varying from 8 to 37 hours
Study Details
To determine typical levels of radiofrequency and microwave radiation resulting from man-made sources in an urban environment
Mobile radiation monitoring equipment was used to measure man-made radiation levels from 20 Hz to 10...
The highest levels measured (approximately 10-2 mW/cm2) originated primarily from AM broadcast tower...
The peak ambient radiation originating from man-made RF sources at the 10 sites monitored in the Washington, D.C., area approached a maximum of 10-2 mW/cm2. This power density may be considered accurate to within 15 dB. If high-powered, low-duty-cycle, pulsed radar signals are considered abnormal and excluded from the totals, the maximum was more nearly 10-3 mW/cm2; and if one is concerned only with average exposure, the maximum would fall even lower. The average background thus is at least two to three orders of magnitude less than any published U.S. recommendation for exposure to RF radiation. Almost the entire power density measured at the monitored sites could be attributed to individual or a combination of commercial broadcasting and high-powered radar installations in close proximity to the test site (i.e., within 1 mile). It is recommended that no further broadband environmental surveys be carried out at this time unless prior calculations indicate their need. Individual AM and FM radio and VHF, UHF, and radar transmitters, however, should be closely monitored to determine exposure levels at populated sites in proximate areas.
Show BibTeX
@article{radiofrequency_and_microwave_radiation_levels_resulting_from_man_made_sources_in_g6572,
author = {Stephen W. Smith and David G. Brown},
title = {RADIOFREQUENCY and MICROWAVE RADIATION LEVELS RESULTING FROM MAN-MADE SOURCES in the WASHINGTON, D.C., AREA},
year = {1971},
}