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Wireless Technology: A review of the Science. How Do we Prove Causation? 1.Temporal Relationship 2.Strength of the Association 3.Dose-Response relationship.

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Presentation on theme: "Wireless Technology: A review of the Science. How Do we Prove Causation? 1.Temporal Relationship 2.Strength of the Association 3.Dose-Response relationship."— Presentation transcript:

1 Wireless Technology: A review of the Science

2 How Do we Prove Causation? 1.Temporal Relationship 2.Strength of the Association 3.Dose-Response relationship 4.Consistency of the association 5.Biologic plausibility 6.Consideration of alternate explanations 7.Experimental evidence 8.Specificity 9.Coherence

3 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

4 The Electromagnetic Spectrum

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6 Safety Code 6 Limits: The “What” and the “Why” RF LimitsWhole BodyHeadTrunk Controlled Environments 0.4 Watts per kg8 Watts per kg20 Watts per kg Uncontrolled environments 0.08 Watts per kg1.6 Watts per kg4 Watts per kg

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8 Comparison of measured RF fields with Wi-Fi RF activity being measured or calculated Maximum time- averaged power density (W/m²) Median time- averaged power density (W/m²) Laptop not communicating with Wi-Fi, measured directly next to Wi-Fi access point 0.0070.000012 Laptop uploading/downloading file, measured 1 metre away from laptop Wi-Fi card 0.0010.000016 Laptop uploading/downloading file, average of measurements taken at different distances from laptop 0.040.00006

9 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

10 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

11 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

12 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 Conclusions


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