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AM Radio Waves May Be Harmful?
Klar writes "Wired News reports that: 'Korean scientists have found that regions near AM radio-broadcasting towers had 70 percent more leukemia deaths than those without.' The article continues: 'The study, to be published in an upcoming issue of the International Archives of Occupational and Environmental Health, also found that cancer deaths were 29 percent higher near such transmitters.' While 'their study did not prove a direct link between cancer and the transmitters', the FDA and the World Health Organization are urging more studies, especially of radio waves from cell phones."
there isn't such a thing as "AM frequencies". that's the problem - AM/FM/SBB often get mixed with VHF/HF/LF/UHF. one thing (AM/FM/SBB etc) is the method of data transmission, the other thing is the wavelength (i.e. frequency).
Cheers,
Erick
http://www.busyweather.com/
The intensity of a 1 watt cell phone within 1 meter is the same as a 50,000 watt tower 223.6 meters. Remember the intensity of radiation will vary 1/radius^2(assuming a perfect sphere)
1) Assume a cell phone antenna is 1 inch away from your head.
2) Assume a 50,000 watt AM transmitter
3) Assume a 1 watt cell phone.
4) We know radio energy diminishes from the source outward at 1/r^2.
5) The square root of 50,000 is approx 224.
So, the energy being pumped into your head by your cell phone is roughly equivalent to standing 224 times farther away from the AM transmitter than your cell phone is from your head (which is one inch).
224 inches is around 19 feet. A 1 watt cell phone pumps more energy into your head than standing 20 feet away from a 50,000 watt AM transmitter.
It pumps more energy into your head than standing 27 feet away from a 100,000 watt transmitter.
-- "A chicken is an egg's way of making another egg."
I agree. There should be a bit of clarification between AM (amplitude modulation) and the region of the electromagnetic spectrum where you tend to find talk radio. If it were all AM frequencies to blame, then this study should have taken a look at airports and commercial pilots. They commonly use AM radio for communication around 120-127 MHz.
/me Runs to the calculator...
.10 m from the phone, then the power passing through it is roughly 8 watts / m^2. (Determining the cross-sectional area of a brain and computing actual power is left as an exercise for the reader.) A 50 kW AM transmitter achieves this density of power at a radius of about 22 meters. So, if the tower is more than 22 meters high, it is safer to stand directly under it than it is to talk on a cell phone.
Well, the power spreads out at a rate proportional to the square of the radius. So, if your brain averages
Unknown host pong.
or
3. "But think of the children"
I actually worked with a group doing mobile phone testing. We found that the radio waves penetrated very deeply into the skulls of children 12 years and younger. At the time it wasn't a problem because there were very few kids of this age with mobiles.
As to whether it caused damage or not... no idea. We just did the physics.
Norman Cook's Ode to Sl
The article says AM broadcasting towers, which means very little. TV signals (at least the NTSC based broadcast over the air in the States) use an AM like signal for the Video and an FM based audio, so depending on your definition they are both a FM and AM broadcast tower. .5 - 1.8 MHz), or do they mean shortwave (I think 3-30 MHz)?
For the AM broadcasting, do they mean the broadcast band (which I think for most of the world is in the range
So what happened to the theory that the energy passing through these sources ionised the air around them, which then in turn caused particles of soot and oil to become electrostatically charged and become attracted to the ground. At least, that was one theory for power lines. The other theory was that the oil used on the power lines contained chemicals like benzene, which were known carcinogens.
Vintage computer adverts: http://www.vintageadbrowser.com/computers-and-software-ads
First it was microwave towers, then power lines, then cell phones.
and somewhere in there was police officers' higher incidence of testicular cancer in those who claimed to use their crotch as a radar gun holster.
my guess is impaired circulation, but hey....
To-do List: Receive telemarketing call during a tornado warning. Check.
This is a much more insightful comment than its parent.
In any case, the amount of power the human body absorbs from a 1500kHz AM signal is phenomenally small. The body is small compared to the signal wavelength (2m/200m=0.01 wavelength), which means it absorbs almost none of the radiated power. The only way it is likely to be a hazard is if you touch a conductor with considerable RF voltage on it. That could give you an RF burn.
A handheld cellular phone emits a maximum of 600mW, but rarely does so in an urban setting. (Remotely mounted antennas are allowed to transmit up to 3W or 4W.) The power emitted is adjusted based upon the tower's reported reception strength. Not only does this conserve battery power, but it helps reduce congestion in the cell network by keeping your signal from straying into the next cell over.
"But it's RF!" you say. So, what is it that RF does? It induces current, and mostly in a conductor the same length (or fraction of the length) as the wavelength of the signal. Now, the 350mm wavelength emitted by an 850mHz transmitter (300,000,000 m/s / 850,000,000Hz = 0.353 meters, or a half length of 0.167 meters (~6-1/2 inches) is actually pretty close to the width of the average skull, so we can assume that the skull will effectively absorb some of that energy. How much?
Interesting ... A quick trip to Google found an Amateur Radio RF Safety Calculator and I entered the following values: 600mW, 2.2dBi gain antenna, 0.1 feet from antenna and 850 mHz, and it tells me that I'm not in the "safe zone" -- I need to be 0.22 feet from the antenna. According to the FCC, the maximum permissible exposure in a controlled area is 2.84 mw/cm^2, but the cell phone is exposing me to 8.5293 mw/cm^2.
I may have to rethink my cell phone usage... :-(
John
Dude, you might be trying to be sarcastic, but not really succeeding. Malaria kills over a million people a year (only recently has AIDS surpassed it).
DDT does get used in Africa, but only after people had to pretty much beg for exceptions to the ban on using it. If they had been able to use it earlier millions of lives could have been saved. But the tree huggers don't care about that, do they?
People couldn't type. We realized: Death would eventually take care of this.
Your comment about warming indicates your age, your lack of historical knowledge, and lack of general education on the environment.
I work thrity feet from this country's best and brightest anadramous salmonid experts and less than 100 meters from the Columbia River. I am a groundwater scientist (licensed hydrologist) working on one of the world's largest radiological cleanup projects. I am over forty and have a great sense of humor.
You are a humorless fuck who thinks he has made a point.
"Rocky Rococo, at your cervix!"
Hmm maybe not. But in the UK things appear to have been a little different.
2 001/press_release_5_01.htm .
1) A 4th March 2001 report by the Sunday Times newspaper starts like this:
'Top scientists establish link
HIGH voltage power cables have been officially linked to cancer for the first time. A study shows that children living near them run a small but significant increased risk of falling victim to the disease. Sir Richard Doll, the epidemiologist who discovered the link between smoking and lung cancer in the 1960s, will this week warn that children living near electricity power lines are at an increased risk from leukaemia. He is also expected to say that there may be a link with adult cancers but that this is unproven. His work was commissioned by the National Radiological Protection Board (NRPB), the government's radiation watchdog. Doll is chairman of its Advisory Group on Non-ionising Radiation (Agnir). He has spent months analysing the results of studies on cancer among people living near power cables. It is the first time a British government body has accepted the link between cancer and power lines.'
2) You can find the actual report dated 6th March 2001 at http://www.nrpb.org/press/press_releases/archive/
First paragraph quote:
'After a wide-ranging and thorough review of scientific research, an independent Advisory Group (Chairman: Sir Richard Doll) to the Board of NRPB has concluded that the power frequency electromagnetic fields that exist in the vast majority of homes, are not a cause of cancer in general. However, some epidemiological studies do indicate a possible small risk of childhood leukaemia associated with exposure to unusually high levels of power frequency magnetic fields.'
Please note that this is a British government body!
The sibling post mentioning visible light raises a point I like.
I'll focus on the physics, however, and your misunderstanding of it. In your post you claim that, according to quantum mechanics, any energy can be ionizing radiation; this is simply not the case. You completely missed the point of quantum mechanics: that the energy states of matter are quantized.
In other words, you have to add at least as much energy as the difference between the two closest energy states for anything to happen, and moreover you have to do it with a single photon--three photons are not the same as one photon with 3x the frequency.
Read up on Einstein and his groundbreaking explaination of the photoelectric effect.