Cell phone radiation question

The subject of cell phones and cancer seems to resurface every so often. What I don’t understand is by which mechanism do proponents of the dangers of cell phones say that the radiation affects the body?

As I understand it (and I might not understand it well) the radiation is already there: EM waves carrying the signal of thousands of cell phones, tv and radio are flying through us 24/7, 365. In my mind all a cell phone is doing is picking up the (non-inozing!) radation that is already there, no? Is the cell phone amplifying the signal in some way, and if so, is it to a level above what you’re experiencing all around you anyway? And if so, how is this type of radiation supposed to be affecting our body?

It’s not the signals being received that are of concern, but rather the signals being transmitted, which are relatively intense. Still, there’s never been a study that conclusively links cellphones to cancer.

The concern at radio frequencies is thermal effects. See specific absorption rate .

>In my mind all a cell phone is doing is picking up the (non-inozing!) radation that is already there, no?

As beowulf said, it’s what your phone transmits that is the problem. To go a little further, you could imagine signalling people with flashlights, and there might be people shining flashlights all over the countryside. What you are more interested in is if you have your own flashlight, whose light is very bright right at the front of the flashlight, can the very bright light right there do some kind of harm? Like, hurt your eye if you hold the flashlight up to your eye and turn it on.

The electromagnetic radiation is beig created by all these things. Your cell phone is one of the sources. It’s not like cell phones use existing radiation that is flying around. They create their own.

I saw this yesterday and was surprised that nobody opened a thread, as it contradicts ‘current understanding’. cite

Is this fuel for the fire and the re-opening of the debate, or a poor study? The Independent article suggests that it has not yet been peer reviewed.

Here’s a current SDMB thread on this topic.

It’s not a new study (but a meta-analysis), it doesn’t show the cause and effect the headlines suggest, it has not been peer-reviewed, it exaggerates, and it is offered by someone who is out to prove his point of view. In short, junk science.

Thanks. I suspected as much. And I don’t know how I missed the other thread!

To wit, electromagnetic radiation disperses spherically, so EMR at twice the distance is only 1/8 as intense. So the signal at your head when you’re talking on the phone is pretty huge when compared to the signal strength when it reaches a cell tower.

I can’t say whether that means it’s dangerous.

Slight hijack: What about bluetooth? If I use my in-the-ear bluetooth headset and my phone is on my hip, am I minimizing the radiation problem (while still using my phone which I must)?

Absolutely, though I don’t think a problem exists, you are certainly radiating your brain much less with a BT headset.

Yeah, but if* radiation from the cell phone is a concern, you’d want to keep it away from rapidly dividing cells in your body. One of the factors for how vulnerable a given tissue is towards damage from radiation exposure is its metabolic rate. Similiarly, errors in the genetic codes caused by radiation are more likely to remain uncorrected, if the damage occurs while the cell is dividing. So, some of the tissues that are a high concern for radiation damage are: bone marrow (in the sternum and the femurs mostly, IIRC) , where red and white blood cells are produced; and the testes, where sperm are produced. Oddly enough - the brain/skull really doesn’t have all that much high reproductive rate tissues. And from what I recall of my rad health physics days, the head has a much higher limit for safe exposure levels than, say, the waist.

So, moving the source of your highest radiation exposure from your head to your waist just doesn’t seem like it would be a very useful exchange.
*an assumption I’m willing to make for the purpose of this argument, but not one that I believe has been proven to be of concern.

I can’t swear to it, but I believe that this concern is for ionizing radiation. Feel free to correct me if I am wrong.

FWIW,
Rob

It’s certainly true that I’m going on my experience with ionizing radiation. I am highly skeptical of cancer risks from non-ionizing radiation, and I can’t claim to have a serious knowledge of the theories of how it is supposed to damage cells and cause cancers. I will say that I’d be shocked to hear that relatively stable, low-metabolic rate cells like brain cells are more at risk than the high metabolic rate cells I’d mentioned earlier.

Totally agree that the entire discussion is hypothetical at best. I, also, do not believe that there is a radiation danger, either from the cell phone or from the bluetooth. I probably should have used “minimize” rather than “mitigate” since the latter suggests some negative effect.

Here’s another take on the news:

I would say that the treatment of this non-story is an indictment of the news media. Unfortunately, it is typical. Scare headlines are their stock in trade; careful, sensible analysis is not.

Dipole radiation (where most of the energy is going) falls as 1/R[sup]2[/sup]. So twice the distance means 1/4 the intensity.

You didn’t get to the reason - although the BT headset is also a transmitter, its signal has to reach only as far as the BT receiver on your hip. The transmit power is very low. The cell phone’s transmit signal back to the cell tower has to reach maybe a few miles, which requires significantly more power.

>To wit, electromagnetic radiation disperses spherically, so EMR at twice the distance is only 1/8 as intense.

Dipole or not, dispersing radiation delivers some power density to the surface of the sphere it is dispersing through, and the area of that sphere, or of a certain constant angular fraction of it, varies as r^2, not r^3. The issue is that what matters is how much power is falling on how much surface area at the target. EMR at twice the distance is 1/4 as intense.