Wireless Technology:
A review of the Science
How Do we Prove Causation?
1.
2.
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4.
5.
6.
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9.
Temporal Relationship
Strength of the Association
Dose-Response relationship
Consistency of the association
Biologic plausibility
Consideration of alternate explanations
Experimental evidence
Specificity
Coherence
What is WiFi?
• Originated as a marketing term for wireless computer
technology, “Wireless Fidelity”, or “WiFi” as a play on
“Hi-Fi”
• Radiofrequency (RF) energy is a form of
electromagnetic energy generated by a source
transmitter and emitted in waves
• Radio and TV broadcasting, cell phones, emergency
radio communications, weather radar and satellite
communications all use RF energy
The Electromagnetic Spectrum
Safety Code 6 Limits:
The “What” and the “Why”
RF Limits
Whole Body
Head
Trunk
Controlled
Environments
0.4 Watts per kg
8 Watts per kg
20 Watts per kg
Uncontrolled
environments
0.08 Watts per kg
1.6 Watts per kg
4 Watts per kg
Comparison of measured RF fields with
Wi-Fi
RF activity being measured
or calculated
Maximum timeaveraged power
density (W/m²)
Median timeaveraged power
density (W/m²)
Laptop not communicating with 0.007
Wi-Fi, measured directly next to
Wi-Fi access point
0.000012
Laptop uploading/downloading
file, measured 1 metre away
from laptop Wi-Fi card
0.001
0.000016
Laptop uploading/downloading
file, average of measurements
taken at different distances
from laptop
0.04
0.00006
Outcome Research
• Review of cellular and animal studies in 2009 found no
evidence of genotoxic effects of RF
• Some cellular studies provided evidence that gene
expression is affected at RF exposure levels close to
current safety limits but it is possible that small
temperature elevations may have accounted for some of
the observations
• Little evidence of cellular effects of RF fields below
current safety limits
• Would be of interest to study modulation patters and
intensity variations corresponding to actual mobile
phones
Outcome Research
• Review of clinical human trials found no evidence for an
association between reported symptoms of
electromagnetic hypersensitivity and exposure to EMFs
• Results from epidemiological studies do not provide
sufficient evidence to support a clear association
between mobile phone use and an increased risk of
cancer
Conclusions
• Research on potential health effects from exposure to
radiofrequency energy is an active field of investigation
• Given inconsistent results, it is possible to cherry pick
the results of individual studies to support a variety of
opinions
• Using a “weight of evidence” approach is more useful for
informing policy making than reliance on individual
studies
Conclusions
• There is general agreement that the exposure limits in
Health Canada’s Safety Code 6 are protective
• Recently published literature demonstrates that Wi-Fi RF
exposures are far lower than with cell phone use
• It is unlikely that all controversies will be resolved even
after decades of additional research