I came across an interesting paper today and thought of this thread immediately. The article is:
Wi-Fi and Health: Review of Current Status of Research, Foster, Kenneth R.[SUP]*[/SUP]; Moulder, John E.[SUP]†, [/SUP]Health Physics, Issue: Volume 105(6), December 2013, p 561–575
It is focussed on Wi-Fi and in particular to do with wifi exposure in schools. It does however summarise the findings ambient RF exposure measurements from multiple sources, i.e. FM, TV, DECT phones, wifi, mobile base stations and other mobile phone users. In broad terms wifi has the lowest exposure levels and mobile phone uplink from other people making phones calls (the exposed person is not making the phone call) has the highest.
It also mentions that wifi levels in a class room with mixed use was limited by the capability of the wired network behind the routers to carry the data. It also made the point that wifi networks have protocols in place so that only one device transmits at any one time.
Millimeter wave scanners used in Australia are advertised as having exposure
to less electromagnetic energy than from a short mobile phone call
http://www.arpansa.gov.au/pubs/factsheets/029is_airportscreening.pdf
Anyway, as per the health part of the title of the paper in Health Physics there is a detailed outline of the effects of RF exposure. It makes for very interesting reading.
The paper tells us that there have been a vast number of studies into possible biological effects since the 1950s and even earlier. Exclude from the database are studies from the former soviet union and warsaw pact countries.
The possible biological effects of RF energy have been investigated by numerous investigators since the 1950s or even before, and now a massive literature exists on the subject. The IEEE ICES database (
http://ieee-emf.com/studysearch.cfm) currently lists 4,408 studies of varying relevance covering the range 300 kHz–300 GHz, going back to the late 1950s
The authors state:
The overwhelming consensus of these reviews is that present evidence does not show the existence of health hazards from exposures below present limits (ICNIRP or IEEE).
It is pretty unequivocal.
They do talk about the classification in 2011 by the International Agency for Research on Cancer of RF as a "possible" human carcinogen, group 2B.
According to the decision rules employed by IARC, this indicates some level of suspicion of carcinogenicity with insufficient evidence to conclude that RF fields are “probable” (group 2B) or “known” carcinogens (group A). The IARC decision was based on “limited evidence” for human carcinogenicity based on epidemiology data, “limited evidence” from long-term animal studies, and “weak mechanistic” evidence (Baan et al. 2011).
So there is limited evidence for carcinogenicity in humans and animals and there is
weak evidence of a mechanism for an effect.
Onto the question of mechanism for effect, the mechanism for effect has been study since the early 20th century. Which pretty much deals with the claim that RF radiation effects are too new to understand the full consequences.
The biophysical mechanisms of interaction between RF energy and biological systems have been studied intensively since early in the 20[SUP]th[/SUP] century. Classic studies by physicists and biophysicists such as Peter Debye (1884–1966) (on electrically induced forces on molecular dipoles), K. S. Cole (1900–1984) (on electrical properties of cells at RFs to study membrane characteristic), and Herman Schwan (1915–2005) (on interactions between RF fields and tissues and cells to address a variety of scientific and health-related issues) provided the theoretical understanding of the interaction of RF fields with biological systems.
The only unequivocal mechanism for
bioeffects of RF energy at realistic exposure levels in the low-GHz frequency range involves heating of tissue
Non-heat related mechanisms for effect have been established and explored theoretically.
However, quantitative analysis shows that very high field levels (which would be very hazardous thermally) would be needed to produce biologically observable effects through these mechanisms.
So to cause a non-heating effect also requires a heating effect. You'll get burnt from the RF before other effects can be observed via other mechanisms. Other mechanisms are also ruled out because the theories do not produce quantitative predictions or because the perturbations produced at realistic exposure levels would be swamped by random thermal agitation.
I'll leave it to the authors to summarise about a mechanism:
“Impossibility” arguments are difficult to sustain in biology; but the lack of a generally-accepted mechanism by which low-level (below ICNIRP and IEEE limits) RF fields in the GHz frequency range could produce biological effects, after many years of sustained efforts to uncover such mechanisms, makes it increasingly unlikely that any mechanism will be found.
The authors then go on to talk about the effects of wifi exposure and in particular note the weakness of the studies and the inconsistent results.
They make an interesting statement that is equally applicable to internet concerns about the health effects of airport body scanners:
Nevertheless, despite the apparent weaknesses of the studies, the reported effects from Wi-Fi exposures have been invoked widely on the Internet to justify claims of hazard from the technology, even as they have been given little weight in risk assessments by health agencies and expert groups.
The lack of a mechanism for harm and the general lack of studies showing an effect for other RF exposure makes me conclude that body scanners are the next unfounded internet worry.
Hi
I've found this thread very interesting and you obviously have professional knowledge on the subject.
You've made the above quote, or words to the same effect, a number of times, always about lack of coughulative effects of RF at low freq. But what about the case of numerous repeated exposures increasing risk? As in: if you go through these scanners 5 times a day every day you would incur a (?? statistically significant ??) higher risk of an adverse effect?
I'm not arguing against your position - just asking about repeated doses rather than coughulative effects.
Personally, I don't give a toss about full body scanners - just another necessary inconvenience. But an absolute blanket 'no exection' rule (if that's hat comes about) would be ludicrous IMHO.
A coughulative effect really is about multiple exposures for ionising radiation. The coughulative effect would cover the situation of going in 5 times a day. But as per the above quick summary there is a lack of a mechanism for effect for RF exposure. (beyond thermal effects).
Sample AFF with no advertisements? More..
