Do CRTs really emit harmful electromagnetic radiation?

V00D00

Golden Member
May 25, 2003
1,834
0
0
It can be harmful for your eyes if your refresh rate is set at 60hz, but the radiation won't do anything.
 

everman

Lifer
Nov 5, 2002
11,288
1
0
Originally posted by: xtknight
Then, can somebody explain what this is all about? http://www.emf-bioshield.com/emf/historique.html I don't know if this is true or not, but if it is, it sure doesn't sound good.

It's about scaring people into buying your product. You don't need a tin-foil hat.
I think there's more comming out the back of a crt than the front iirc?

edit: wow I actually looked at the item they're selling, 4 little light bulb things for $150 to stick on your monitor :Q
 

Mark R

Diamond Member
Oct 9, 1999
8,513
16
81
It depends how old your CRT is - if it is more than about 25 years old, then there may be some harmful ionising EM radiation (X-rays) emitted from the tube itself, and also from the flyback rectifier.

When it was discovered that X-rays were harmful, CRT designs were changed - tubes were made from lead glass (to provide shielding), voltages were strictly controlled (legal limit is about 27,000 V these days - before that 30-40,000 might not have been uncommon), and solid-state rectifiers no-longer emit X-rays.
 

Gibsons

Lifer
Aug 14, 2001
12,530
35
91
Originally posted by: xtknight
Then, can somebody explain what this is all about? http://www.emf-bioshield.com/emf/historique.html I don't know if this is true or not, but if it is, it sure doesn't sound good.


Imo, there's a severe lack of controls and explanations on all that data. They don't explain their data well and don't do anything to see if their effects are simply due to say, light from the crt. They don't tell you what CRT they used (maybe it's a 30 year old job). None of it looks to be peer reviewed. I suspect the apoptosis data wouldn't get past peer review without more quantitative assay. They show some (imo rather unconvincing, but I'm no pathologist) slides and state what their results are. No mention of whether they did the assessment in a double-blind study (bet they didn't) or how they controlled for variations in staining.
 

Mark R

Diamond Member
Oct 9, 1999
8,513
16
81
Yikes. I'd given their data a miss earlier as I didn't have time to read it in detail.

Well, I can see no peer-reviewed publications - just a lot of abstracts (most of very dubious quality) and conference presentations. Their 'full text' experimental reports are also very vague and short on detail - for example their Daphnia mortality experiment doesn't actually state how many Daphnia they examined, just that there was a different mortality in the various experimental groups! There is no discussion of statistics, controls or of potential confounding.

Similarly, their testicular apoptosis experiment is poorly explained and data-challenged where most important (i.e. number of cells examined, and number of abnormalities shown), no discussion about who examined the slides, and their experience - nor whether there was any double checking of these results (examining of slides is quite subjective, and there can be significant variability between one person and another). There was also no objective testing done (immunocytochemistry for apoptosis markers is now available, but might not have been at the time that experiement was performed).
 

xtknight

Elite Member
Oct 15, 2004
12,974
0
71
Originally posted by: Mark R
It depends how old your CRT is - if it is more than about 25 years old, then there may be some harmful ionising EM radiation (X-rays) emitted from the tube itself, and also from the flyback rectifier.

When it was discovered that X-rays were harmful, CRT designs were changed - tubes were made from lead glass (to provide shielding), voltages were strictly controlled (legal limit is about 27,000 V these days - before that 30-40,000 might not have been uncommon), and solid-state rectifiers no-longer emit X-rays

Oh, okay. That was just something my dad worried about. Chances are, in his day, the CRTs were very dangerous. Thanks for explaining it all.
 

xtknight

Elite Member
Oct 15, 2004
12,974
0
71
What about LCDs?

Laptops and Radiation
Another common misconception about non-ionizing radiation is that laptop computers with liquid crystal displays (LCDs) do not emit radiation. By its nature, the LCD's need for current is minuscule; therefore, an LCD emits very low levels of magnetic fields. However, LCDs emit correspondingly high levels of electric fields. An exception to this is the more popular version of the LCD, the backlit display. Backlit displays, unlike their lower resolution, lower contrast predecessors, can emit significant levels of both magnetic fields and electric fields.

http://www.noradcorp.com/2tutor.htm

[sarcasm]I think we're all going to die someday by sitting in front of our monitors :(.[/sarcasm] Honestly though, is this not like cell phones near our heads but just a little farther? I'm not trying to scare people off of their PCs, I just wondered. I used to get bad aches in the back of my neck, but ever since I started using LCDs I don't have this problem anymore. Could this be related?
 

genghislegacy

Member
Jan 21, 2005
100
0
0
yes it's harmful, but the front side is ok, just don't sit at the back of a monitor all day - the back emits much more radiation.
 

thomrk

Junior Member
Jan 11, 2005
5
0
0
Website gives the appearance of junk science. Says product counteracts EMF but that scientists can't measure such low levels, and product counteracts CRT EMF despite EMF patterns being different for each model monitor and perhaps even with placement of said monitor. Counter-EMF generation is built into some monitors, through extra winding in flyback connected to antenna positioned so emissions are exactly out of phase with flyback's other emissions.

If worried about EMF, replace CRT with LCD.
 

Spencer278

Diamond Member
Oct 11, 2002
3,637
0
0
If it was harmful then I'm sure every maker of CRT or LCD would be sued many times by now. There not being sued so there for I think they are safe.
 

SagaLore

Elite Member
Dec 18, 2001
24,036
21
81
Originally posted by: Spencer278
If it was harmful then I'm sure every maker of CRT or LCD would be sued many times by now. There not being sued so there for I think they are safe.

Nah, nobody is suing cookware manufacturers even though aluminum leeches into food which is linked to alzheimers or heated scratched teflon coating produces fumes toxic enough to kill birds.
 

Geomagick

Golden Member
Dec 3, 1999
1,265
0
76
Originally posted by: genghislegacy
yes it's harmful, but the front side is ok, just don't sit at the back of a monitor all day - the back emits much more radiation.



That's really reassuring to those who work in a high density office.

 

SagaLore

Elite Member
Dec 18, 2001
24,036
21
81
Originally posted by: George Powell
Originally posted by: genghislegacy
yes it's harmful, but the front side is ok, just don't sit at the back of a monitor all day - the back emits much more radiation.



That's really reassuring to those who work in a high density office.

Didn't you know, those cubicle walls are lead shielded! ;)
 

Calin

Diamond Member
Apr 9, 2001
3,112
0
0
Originally posted by: xtknight
What about LCDs?

[sarcasm]I think we're all going to die someday by sitting in front of our monitors :(.[/sarcasm] Honestly though, is this not like cell phones near our heads but just a little farther? I'm not trying to scare people off of their PCs, I just wondered. I used to get bad aches in the back of my neck, but ever since I started using LCDs I don't have this problem anymore. Could this be related?

I'd say it was related to using a worse position while using a CRT monitor than with the LCD. It was just hours after hours of sitting there, in a position painful for the neck muscles.

Calin
 

L00PY

Golden Member
Sep 14, 2001
1,101
0
0
Originally posted by: SagaLore
Nah, nobody is suing cookware manufacturers even though aluminum leeches into food which is linked to alzheimers or heated scratched teflon coating produces fumes toxic enough to kill birds.
Funny how myths die hard. Google it. Any evidence out there is tenuous at best.

As for Teflon fumes, it doesn't have to be scratched. Birds are very sensitive to fumes and will die at much lower exposure levels. Ever hear the expression "canary in a coal mine"? Polytetraflouethylene fumes during cooking should be the least of your concerns. Now if you wanted to complain about toxicity during the manufacturing process or their persistance in the environment, you might have a leg to stand on -- but "fumes toxic enough to kill birds" is nonsensical when talking about human risks.
 

SagaLore

Elite Member
Dec 18, 2001
24,036
21
81
Originally posted by: L00PY
Originally posted by: SagaLore
Nah, nobody is suing cookware manufacturers even though aluminum leeches into food which is linked to alzheimers or heated scratched teflon coating produces fumes toxic enough to kill birds.
Funny how myths die hard. Google it. Any evidence out there is tenuous at best.

Nice search, all of the results talk about aluminum being linked to alzheimers. What is the "myth" you're talking about? A collection of aluminum in the brain was observed in alzheimers patients, it was part of a scientific study.

Polytetraflouethylene fumes during cooking should be the least of your concerns.

Why? Canaries died in coal mines because of gas leaks which were harmful to humans as well, the birds just gave the faster warning.
 

Calin

Diamond Member
Apr 9, 2001
3,112
0
0
Canaries died when there was not enough oxygen or when the methane concentration was too big. The oxygen concentration problem was solved with the help of electric fans, and the detection of methane with Auer lamps. No longer were the canaries needed.
 

L00PY

Golden Member
Sep 14, 2001
1,101
0
0
Originally posted by: SagaLore
Nice search, all of the results talk about aluminum being linked to alzheimers. What is the "myth" you're talking about? A collection of aluminum in the brain was observed in alzheimers patients, it was part of a scientific study.
Bah. I would have thought HT would have been able to sort out the general web dross. Or seeing that those sites claiming a definitive link have little or no research to support their position. If you couldn't see the junk in the previous basic search, try this slightly revised google search. Or better yet, from that search, there's this pdf that shows that there's contradictary results for any possible Al-AD link.

Just examining the numbers highlites the implausibility of a cooking pan - AD link. Average daily intake of aluminium from using aluminum saucepans can be as low as 0.1% of your total aluminum intake for the day. Actual absorbtion of aluminum via your dietary tract may be as low as 0.01%. Depending on where you live, you might even be inhaling more aluminum than you eat.

Polytetraflouethylene fumes during cooking should be the least of your concerns.
Why? Canaries died in coal mines because of gas leaks which were harmful to humans as well, the birds just gave the faster warning.
The key was "fumes toxic enough to kill birds" doesn't mean a whole lot when talking about toxicity in humans. Canaries were much more sensitive to environmental risks and died at levels much lower than would kill humans. They indicated conditions were worsening to levels that might put humans to risk. Just toxic enough to kill birds doesn't mean that they'll kill us too. Now if were to say "fumes toxic enough to kill an ox", that would actual suggest that the fumes are bad to us too.

Also, that you were mistaken about Teflon needing to be scratched further evidenced your lack of understanding of the risks involved. What's hyped in the media is often not the thing to be most concerned about. The media is interested in "getting good print" and will rarely present the dissenting side or even the retratction with the same level of enthusiasm.
 

Jeff7

Lifer
Jan 4, 2001
41,596
19
81
Originally posted by: everman
Originally posted by: xtknight
Then, can somebody explain what this is all about? http://www.emf-bioshield.com/emf/historique.html I don't know if this is true or not, but if it is, it sure doesn't sound good.

It's about scaring people into buying your product. You don't need a tin-foil hat.
I think there's more comming out the back of a crt than the front iirc?

edit: wow I actually looked at the item they're selling, 4 little light bulb things for $150 to stick on your monitor :Q

Actually, I think a tinfoil hat would work better than the stuff that scam site is selling.
The EMF-Bioshield® protection system is made of two small spheres (or mini-bulbs) of 25 mm in diameter in neutral plastic. They contain solutions of rare earths salts with specific electromagnetic properties.
Rare Earth salt????

I'd love to get a few hundred of them. I have a nice little EMF detector right here. I have a funny feeling that it won't register a change. Of course, that's probably because it doesn't detect the quantum electro-ferrant resonant frequency phase shift that the Rare Earth Salt imprints in the outgoing EM radiation. :p

The usualy disclaimer about CRT's:
Go outside. It's more dangerous. Sunlight is electromagnetic radiation that is PROVEN to cause skin cancer. Go ahead and try it yourself. After an hour outside in the direct sun, I'll bet that you'll experience more adverse effects than you would from setting your head against your monitor for a week.


Holy farking shiznit, Batman!!!
EMF-Bioshield® System 1: US $115.00
(for screens with a diagonal dimension of up to 14"), and

EMF-Bioshield® System 2: US $140.00
(for screens with a diagonal dimension from 15" to 30").

A S&H $10.00 charge is added per set (sliding scale with multiple orders).

I'd rather have Rare Earth MAGNETS. Geez, think of how many magnets you could get for $115....Damn.
I wish I didn't have any moral values. Making money is easier that way. They're going all out to part fools and their money. At least make it $19.95, like everything else costs. :)
 

SagaLore

Elite Member
Dec 18, 2001
24,036
21
81
Originally posted by: L00PY
Originally posted by: SagaLore
Polytetraflouethylene fumes during cooking should be the least of your concerns.
Why? Canaries died in coal mines because of gas leaks which were harmful to humans as well, the birds just gave the faster warning.
The key was "fumes toxic enough to kill birds" doesn't mean a whole lot when talking about toxicity in humans. Canaries were much more sensitive to environmental risks and died at levels much lower than would kill humans. They indicated conditions were worsening to levels that might put humans to risk. Just toxic enough to kill birds doesn't mean that they'll kill us too. Now if were to say "fumes toxic enough to kill an ox", that would actual suggest that the fumes are bad to us too.

You can't sue someone if you're dead. You can if you get sick though. However not deadly it is, it's still toxic and harmful to your body.

Here's a cool Science project on aluminum and iron cookware.

The pdf you showed me is completely inconclusive, although it's a nice read. It states that for every study suggesting that aluminum may be linked, there is another study that could not confirm the results. It does not say that those studies invalidated the previous studies, just that they're still inconclusive.

Let's look at few of the things it does admit - Aluminum is known to be toxic to the nervous system, aluminum promotes aggregation of the protein fragment beta-amyloidal into the amyloidal plaques that are a hallmark of Alzheimer abnormality, studies finding the most consistent link have examined elevated levels of aluminum in drinking water and increased incidence of Alzheimer's.

On the flipside, some studies do not show elevated aluminum in the Alzheimer brain, research has failed to document a clear elevation of Alzheimer risk in individuals with occupational exposure to aluminum, there is no evidence that Alzheimer's disease is more prevalent in cultures that drink large amounts of tea (the leaves accumulate large amounts of aluminum).

So when I look at these two sets of data, my conclusion is that Aliminum is clearly risk, but scientists haven't quite figured out why. The problem is how you get aluminum into your body. Cookware, foil, soda cans, and pipes are made of elemental aluminum. Foods contain natural aluminum compounds that are compatible with our system. Concerning the statement about tea leaves: Elemental analysis of tea leaves The aluminum that is in them are another compound, not elemental aluminum.

The ignore all of this is... ignorance, or denial.
 

L00PY

Golden Member
Sep 14, 2001
1,101
0
0
Originally posted by: SagaLore
Let's look at few of the things it does admit - Aluminum is known to be toxic to the nervous system, aluminum promotes aggregation of the protein fragment beta-amyloidal into the amyloidal plaques that are a hallmark of Alzheimer abnormality, studies finding the most consistent link have examined elevated levels of aluminum in drinking water and increased incidence of Alzheimer's.
Ignorance or denial? Kind of how you deny the other half of what you quoted?

"Aluminum is known to be toxic to the nervous system" vs. "Aluminum is known to be toxic to the nervous system, but its effects differ from those of Alzheimer's disease"?

"Aluminum promotes aggregation of the protein fragment beta-amyloidal into the amyloidal plaques that are a hallmark of Alzheimer abnormality" vs "There is some evidence that in laboratory cultures of nerve cells, aluminum promotes aggregation of the protein fragment beta-amyloidal into the amyloidal plaques that are a hallmark of Alzheimer abnormality. However efforts to correlate aluminum levels with plaque density in people with Alzheimer's have been inconclusive."

That there's contradictary data suggests that there isn't a clear Al-AD link. If there were a direct link like you first suggested, it'd be much easier to identify. It's much more likely that there's a confounding factor that's not being corrected for in the experimental design. Bottom line, aluminum exposure (and especially that from pans) is not a significant risk factor. Of course it's just only the World Health Organization, the NIH, the EPA, and Health Canada that happen to agree with me. :roll:
 

SagaLore

Elite Member
Dec 18, 2001
24,036
21
81
Originally posted by: L00PY
Originally posted by: SagaLore
Let's look at few of the things it does admit - Aluminum is known to be toxic to the nervous system, aluminum promotes aggregation of the protein fragment beta-amyloidal into the amyloidal plaques that are a hallmark of Alzheimer abnormality, studies finding the most consistent link have examined elevated levels of aluminum in drinking water and increased incidence of Alzheimer's.
Ignorance or denial? Kind of how you deny the other half of what you quoted?

"Aluminum is known to be toxic to the nervous system" vs. "Aluminum is known to be toxic to the nervous system, but its effects differ from those of Alzheimer's disease"?

That fact that it's toxic to the nervous system, and the fact that the brain is mostly nervous tissue, suggests a great potential in problems with increased aluminum in the brain. It's doesn't matter that the effects are different. The article doesn't even mention what this difference is.

"Aluminum promotes aggregation of the protein fragment beta-amyloidal into the amyloidal plaques that are a hallmark of Alzheimer abnormality" vs "There is some evidence that in laboratory cultures of nerve cells, aluminum promotes aggregation of the protein fragment beta-amyloidal into the amyloidal plaques that are a hallmark of Alzheimer abnormality. However efforts to correlate aluminum levels with plaque density in people with Alzheimer's have been inconclusive."

Some and inconclusive. Whoopdie-do, let's go have some aluminum pie. The inconclusion is about specific comparisons of plaque density, and does NOT negate any of the other observations.

That there's contradictary data suggests that there isn't a clear Al-AD link.

If it were 100% clear, would we be having this argument? Science is based on emperical evidence, a lot of testing and confirmation goes into the process. It's an even harder process when dealing with organic life, especially when you have a human brain to examine across about 80 years. I am not a scientist. I am a person with common sense.

Perhaps we should start some more threads on aspartame and mercury amalgams. ;)