An Analysis Of Radiofrequency And Microwave Absorption Data With Consideration Of Thermal Safety Standards
Richard A. Tell · 1978
The analysis identifies a resonance frequency range of 10 MHz to 1000 MHz where whole-body thermal loads can exceed the basal metabolic rate several times over at the current U.S. safety standard.
Plain English Summary
The report analyzes existing radiofrequency and microwave absorption data to examine frequency-dependent tissue heating and determine exposure field intensities linked to thermal loading on the whole body and specific tissues in adults and infants. A baseline absorption factor of 1 W/kg, equivalent to the adult basal metabolic rate averaged over total body mass, is used for comparison. In the 10 MHz to 1000 MHz range, absorption can produce whole-body thermal loads several times the basal metabolic rate at the present U.S. safety standard.
Why This Matters
Individual organs have metabolic rates that differ widely from the whole-body average, with heart muscle at 33 W/kg, brain at 11 W/kg, kidney at 20 W/kg, liver at 6.7 W/kg, skeletal muscle at 0.7 W/kg, and skin at 1 W/kg. A theoretical whole-body RF/MW heat load of 1.4 W/kg could raise head core temperature by up to 0.2°C and muscle temperature by up to 1.5°C.
Finding
A method of specifying safety standard limits based on the electromagnetic field energy density rather than the plane wave, free-space equivalent power density is presented. The analysis reveals a particularly important resonance frequency range, 10 MHz < f <1000 MHz, in which RF and MW absorption may lead to whole body thermal loads several times the whole body basal metabolic rate for exposures equal to the present safety standard in use in the United States.
In their words
“A method of specifying safety standard limits based on the electromagnetic field energy density rather than the plane wave, free-space equivalent power density is presented. The analysis reveals a particularly important resonance frequency range, 10 MHz < f <1000 MHz, in which RF and MW absorption may lead to whole body thermal loads several times the whole body basal metabolic rate for exposures equal to the present safety standard in use in the United States.”
Exposure Details
- SAR
- 1 W/kg
Exposure Context
This study used 1 W/kg for SAR (device absorption):
- 2.5x above the Building Biology guideline of 0.4 W/kg
Building Biology guidelines are practitioner-based limits from real-world assessments. BioInitiative Report recommendations are based on peer-reviewed science. Check Your Exposure to compare your own measurements.
Where This Falls on the Concern Scale
Show BibTeX
@article{an_analysis_of_radiofrequency_and_microwave_absorption_data_with_consideration_o_g4531,
author = {Richard A. Tell},
title = {An Analysis Of Radiofrequency And Microwave Absorption Data With Consideration Of Thermal Safety Standards},
year = {1978},
}