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  Reply # 1408038 16-Oct-2015 19:40
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Talkiet:
nunz: [snip]

Rf does do stuff - that's why they have defined safe limits. If it wasnt considered some kind of harmful we wouldn't have safe limits imposed on it - they dont impose safe limits on clean drinking water, breathing air, etc.

RF does have some effect.  however long term, low level exposure to kids who are more susceptible - like I asked - anyone know of any studies or has any thoughts on the fact there are now 60-180 radiating devices within detectible distance of kids, 30 hoursper week?

At the very least schools should be teaching basic health and safety stuff like dont put laptops on your knees, put it on a tray or even better, on a desk.


But you're not right here either...

Water is lethal in high doses - and I'm not being clever and talking about drowning or having a massive icecube smack you in the head.

http://www.compoundchem.com/2014/07/27/lethaldoses/

There are _MUCH_ better things for schools to teach than to frighten children with things that the broader scientific community is very comfortable about. Now if new research or methods change the prevailing commonly held and supported position then I'll change my mind... (obref: https://www.youtube.com/watch?v=HhGuXCuDb1U )

Cheers - N



I never suggested teaching kids to be afraid - although putting a laptop on your leg will give you a bad burn if you are not careful - its also bad for laptop as it tends to block air inlets.

The reason they don't teach lethel does of water is the chances of doing that in one dose without puking your guts out are pretty high. In fact you ar emore likely to rupture than die from toxic effect.

They do however define safe EMF levels for equipment  - because there is obviously some level of possible EMF that could be practically given that is dangerous.

Re laptops and trays:
http://www.webmd.com/skin-problems-and-treatments/news/20101004/laptop-risk-toasted-skin-syndrome
https://www.tumblr.com/search/laptop%20leg%20burns
http://mieuxprevenir.blogspot.co.nz/2013/05/skin-conditions-from-using-notebook-on.html




nunz

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  Reply # 1408041 16-Oct-2015 19:51
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nunz:
Sideface:
nunz: ...  There are some people who cant be in rooms or areas with RF, cell phones, Cell phone towers etc - it gives them headaches, ringing in the ears, sight issues, migraines etc etc. Scientifically proven. ...


This is all news to me.

Can you give us the "scientific proof" / reference ?


http://onlinelibrary.wiley.com/doi/10.1002/bem.20247/abstract

https://en.wikipedia.org/wiki/Electromagnetic_hypersensitivity   ...



From the above reference as cited by you :

Electromagnetic hypersensitivity

"The reported symptoms of EHS [Electromagnetic Hypersensitivity] include headache, fatigue, stress, sleep disturbances, skin symptoms like prickling, burning sensations and rashes, pain and ache in muscles and many other health problems. ... However, there is no scientific basis to link EHS symptoms to electromagnetic field exposure."

"The majority of provocation trials to date have found that self-described sufferers of electromagnetic hypersensitivity are unable to distinguish between exposure and non-exposure to electromagnetic fields, and it is not recognized as a medical condition by the medical or scientific communities. Since a systematic review in 2005 showing no convincing scientific evidence for its being caused by electromagnetic fields, several double-blind experiments have been published, each of which has suggested that people who report electromagnetic hypersensitivity are unable to detect the presence of electromagnetic fields and are as likely to report ill health following a sham exposure as they are following exposure to genuine electromagnetic fields ..."

You are asking some very good questions:

How much EMF exposure is "safe"?  ... for adults? ... for children?

From my reading on this controversial topic, most people who have suffered alleged long-term damage due to EMF exposure were symptom-free at the time of their exposure(s) - which makes the epidemiology even harder to interpret.






Sideface


 
 
 
 


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  Reply # 1408042 16-Oct-2015 19:51
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nunz: [snip]

They do however define safe EMF levels for equipment  - because there is obviously some level of possible EMF that could be practically given that is dangerous.


And that's where I don't necessarily agree with you.

There might be other reasons to put warnings on things. After all McDonalds warn people that coffee is hot, Toaster manufacturers and curling iron makers warn people not to use them in the shower and the companies that sell packaged peanuts put honking great warnings on packets of peanuts that THEY MAY CONTAIN PEANUTS.

In many, many, many cases the published safe levels of [many things] are several orders of magnitude different from levels where any measurable real world effect would be apparent.

I believe that the "safe levels" of many things, including EMF constitute useless knowledge UNLESS all the constraints, assumptions and worst case scenarios, safety margins etc are also included in the warnings - and they never are. You have a number, with NO CONTEXT. That's just not useful.

Maybe (and I'm making this up) the safe EMF levels for lets say Wifi, are based on the assumption of a transmitter, locked at full power, strapped to the head of a 1 year old child 24*7... Now with the multitude of (assumed) factors there, explain how ANYONE could possibly get a useful actionable bit of information out of that for a home situation, where the transmitter is often at low power, inhabited by only teenagers and above, who aren't even there most of the day. I'm also going to assume they don't strap the transmitter to their head most of the time - at least since texting overtook phonecalls.

Cheers - N




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  Reply # 1408044 16-Oct-2015 20:09
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The discussions on EMF are similar to the EMF type studies done on Trasnformers, sub stations and power lines. most of it was rubbished but more and more studies showing strong correlations between high voltage powerlines, transformers and substations - especially in children

Powerlines- again an EMF source.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2247309/
http://www.tandfonline.com/doi/abs/10.1080/10428190802441347
The research fluctuates but interestingly there seems to be a correlation not in the first round of exposed subjects but the children of exposed subjects and/or the ability to inhibit cancers being reduced rather than cancer promotion per se.




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  Reply # 1408047 16-Oct-2015 20:23
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If you are concerned you can get one of these .....




DRZ  Smarterer


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  Reply # 1408052 16-Oct-2015 20:39
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nunz: The discussions on EMF are similar to the EMF type studies done on Trasnformers, sub stations and power lines. most of it was rubbished but more and more studies showing strong correlations between high voltage powerlines, transformers and substations - especially in children

Powerlines- again an EMF source.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2247309


The 95% confidence intervals all include 1 in other words there is no difference in risk. (1989 is a very old study)

A.



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  Reply # 1408054 16-Oct-2015 20:42
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NHI reference on emf and cancer.

http://www.cancer.gov/about-cancer/causes-prevention/risk/radiation/magnetic-fields-fact-sheet

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  Reply # 1408074 16-Oct-2015 21:53
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As you're aware radiation levels are subject to an inverse square law, and this is why on your roof at Lincoln (or aboard ships) you have 'safe' or 'restricted' zones.
And putting this in context; because it helps with your 60 units in a room scenario; imagine that I ask you to stand next to, and wide-eyed, looking directly into a 100watt light bulb.It would cause your eyes irreparable damage after a short period of time. But stare at that bulb from a metre away and the damage will be les permanent.
Put 60 bulbs in the room and that's unlikely to change as the total light is not from a single point source, and you're at varying distances from all sources.

As an aside:
In a previous life I did find I was sensitive to EMF and could tell within a short time of walking into a room if there was an active RF source operating. Maybe there was an association with an RF burn I'd got from holding a live coax onto an antenna for a short time (150megs @ 25watts). Not to be wished on anyone.
Whatever the cause of my sensitivity ithers didn't have it.

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  Reply # 1408081 16-Oct-2015 22:33
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Those 60 Wifi client devices in 1 room won't all be transmitting at the same time. Even if they all tried to transfer data at the same time. The speed will be really slow. As they all have to take turns using the limited bandwidth. So 60 devices won't mean 60X the radiation of 1 device. (Compared to that 1 device transmitting continuously). And also all of the laptops will probably be downloading far more data than uploading. Which means most of the RF radiation will be coming from the Wifi Access point. Which will be high up on the ceiling or wall. Not right next to 1 of the kids. And my understanding of how laptops are constructed, The Wifi aerial is inside the top of the screen. So placing the laptop on your knees won't make much difference to your RF exposure.

And haven't bothered reading any of the above linked stuff. But do those studies have proper control groups? As kids who have lower RF exposure are probably outside more. Getting exercise, And probably have better diets. Im assuming here that RF exposure means time spent using laptops / tablets / cellphones / playing computer / video games ect. And guessing that parents who allow their kids to spend all their time using electronic devices on average probably don't make sure their kids get enough exercise ect. As kids electronic device usage will be heavily influenced by the parenting style of the kids parents. So any study author will have to be careful that they are actually measuring RF exposure. And not indirectly exercise, diets or anything else that will definitely affect health.





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  Reply # 1408085 16-Oct-2015 23:09
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As PeterReader says.. "Here we go again..."

One point I thought of was that realistically most NZ Primary classrooms are around 30 kids (not 60?), and the majority of Primary Schools don't have 1:1 devices for students..

I think that if EMF exposure was a legitimate concern then electronic devices as we know them today would not be as successful as they are. You can just put on your tinfoil hat :)

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  Reply # 1408088 16-Oct-2015 23:37
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It's very easy to prove conclusively something that is common.
It's very difficult to prove conclusively something that is very uncommon.
It's impossible to prove conclusively something does not cause something very uncommon. We say there is no evidence that X causes Y.

I personally would channel my worries on more common causes of cancers.

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  Reply # 1408089 16-Oct-2015 23:47
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There is some evidence that prolonged mobile phone usage is linked to higher rates of brain cancer in children

1. This is not enough to prove that X causes Y.
2. It is not possible to prove because you have to randomly get some kids and make 1 group use phones and make the other not use phones for a period of say 10 years.
3. Mobile phones are used very close to the brain.
4. Wifi is not used very close to the brain/genitals/etc
5. I am no scientist and cannot translate the equivalence of strength of EMF of mobile phone vs wifi device vs wifi router.

6. I would channel my worries on more common causes of problems in children.

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  Reply # 1408101 17-Oct-2015 04:39
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Sugarloaf probably has many thousands x the power of a WiFi AP

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  Reply # 1408103 17-Oct-2015 06:51
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nathan: Sugarloaf probably has many thousands x the power of a WiFi AP


sugarloaf is 64 kW, a unifi UAP-LR is 500mW, so about 128 thousand times more

to the OP, find and read NZS 2772.1:1999, it contains all the info you need to know about Radiofrequency fields - Maximum exposure levels - 3 kHz to 300 GHz

gzt

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  Reply # 1408169 17-Oct-2015 11:35
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Ministry of Health study:

"All exposures were very low compared with the public exposure limit in New Zealand Standard 2772.1:1999 Radiofrequency Fields Part 1: Maximum exposure levels 3 kHz – 300 GHz. The maximum exposure averaged over six minutes was equivalent to 0.024% of (ie, about 4000 times lower than) the reference level specified for the public in that Standard, and generally, in a classroom with a WiFi access point mounted on the wall, time average exposures were less than 0.01% of the limit (10,000 times lower). In classrooms without an access point, exposures were lower still.

Time average exposures measured 30 cm from a laptop were generally less than 0.001% of the reference level. The results indicate that the duty cycle of devices is typically less than 0.005 (ie, the devices transmit for a total of less than 18 seconds in every hour). "

http://www.health.govt.nz/publication/snapshot-study-wifi-in-schools

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