Many of my friends in Fairfield, Iowa, are in an uproar right now about a new cell-phone tower that, unlike the existing two towers on the outskirts of town, is near homes and a few blocks from an elementary school. Here's some of the existing press about the controversy:
I first heard about the controversy when I passed through Fairfield a few weeks ago. My friends who picked me up at the train station made a good case for their opposition to the tower. Don't get me wrong, I think there are good reasons to oppose cell phone towers in one's neighborhood: they're ugly, and they're not good neighbors.
Of course, the site in question is right next to the railroad tracks, which carry some 18 trains a day, and in my experience are uglier and much, much worse neighbors than any tower. Anyone who lives within half a mile of the tracks is already demonstrating a high capacity for tolerating ugliness and bad neighborliness. There are also several electrical substations in town, which are also ugly and bad neighbors, but they've been there for decades so no one pays them any mind.
Where I disagree with the protestors is about the possible health effects. The only mechanism anyone can suggest for health effects is the radio-frequency radiation (RF) put off by the antenna, a kind of electromagnetic field (EMF). New-age philosophy aside, EMFs are scientifically measurable with instruments, so my question for my friends was, if you're so concerned about exposure, shouldn't you get a meter and actually measure the EMFs in your home, in the existing school building, and at the foot of a cell tower? Maybe there are other sources of EMFs already in your environment that are far more concerning, such that the cell tower's contribution to your exposure is not significant.
I know Fairfield well enough to know that this was a rhetorical question, but after asking it a handful of times, I started to wonder, why don't I get a gauss meter and measure some EMFs, so I can show the data to other people? I just got curious.
Turns out, they're quite affordable. Here's the one I got: http://drgauss.com/ -- I found it for $35 including shipping. Note that the sales pitch makes it sound like EMFs are quite harmful. The instruction manual that comes with the device has some similarly alarming claims, but also has a disclaimer saying that the company does not endorse any of those claims! In other words, they're good enough for the sales team, but not for the guys who write the documentation!
On a side note, the company's other Web site, http://safelevel.com, discredits the stick-on "radiation shields" that many Fairfielders attach to their cell phones, saying, "Other devices that stick to the phone and claim to reduce fields are can actually interfere with reception and cause the phone to emit higher fields than necessary (the phone adjusts its output according to reception quality)." (emphasis added) But I digress.
Anyhow, right after the disclaimer is an introduction that says, "You have purchased a meter that will allow you to detect and measure two very different types of fields." (emphasis added) "The first one is the radiation emitted from mobile phones. It is commonly known as Radio Frequency (RF) radiation. The second ... is that generated by electrical current. These fields are known as Power Frequency Electromagnetic Fields ... and are also known as Extremely Low Frequency (ELF) Electromagnetic Fields (EMFs)."
OK, so RF from mobile phones is "very different" from ELFs, being at a higher frequency. But the meter doesn't distinguish! It has two scales on its face, but it doesn't give any indication which one to read! That's a frustration. If only I hadn't just been told that they were very different, I wouldn't mind so much.
So I read on... turns out that the RF the meter was designed to measure was the kind produced by analog phones, and that digital phones (CDMA, PCS, GSM) produce far less radiation over a much wider spectrum for a fraction of the time of their analog counterparts, such that it is nearly impossible to measure the RF output of a modern digital phone. In fact, after telling you how to do a "bench test" of your phone, the manual admits, "...the meter's readings are not conclusive. Proper measurements of RF radiation from mobile phones require the use of professional equipment costing thousands of dollars." (emphasis added)
As I understand it, exposure to an EMF has three facets: quality, quantity, and duration.
Quality is the frequency of the transmission. Some cell phones (notably the newer, digital ones) operate in the microwave part of the spectrum, and that in itself alarms some people because of the connotation to cooking food, but only a very small range of frequencies will cook food, and the many other uses of microwaves operate outside that range. Other appliances, as the meter's manual pointed out, are more likely to radiate at the frequency of the AC power they use, which is much much lower than microwaves.
Quantity is the strength of the field, which is what the meter measures, and which decreases inversely with the square of the distance. So a cell phone antenna 80 feet off the ground would have to be broadcasting at 6400 times the power as a handset one foot away to be more damaging to one's health. Or sticking to what we can measure, standing 10 feet away from a poorly-shielded appliance would be 1000 times less harmful (presuming for the moment that it is harmful) than standing a foot away.
Duration is a tougher nut to crack, and the one my friends fell back on in our discussions: even if the fields are weak, they say, and even if they are in a harmless part of the spectrum, surely it can't be good to be exposed to them all day long, in one's home or school. Which is why I bought the meter in the first place: maybe we and our kids are already being exposed to fields all day long in our homes and schools, and we just don't know it!
The meter is easy to use, with a light and sound that come on when the probe measures more than the recommended 2 milliGauss threshold. The tricky part is that it measures 3-D fields in one dimension, and the fields are amorphous and wiggly, so you have to measure several times to be sure where the 2 mG threshold lies.
Here are a few of the more notable fields I found in our home.
|source||2 milliGauss threshold ("safe" distance)|
|electric stove, on high||5 feet from burner|
|refrigerator, running||5 feet from sides, 1 inch from front|
|power strip for entertainment center||4 feet|
|microwave oven, running||2 feet from sides and top, 1 foot from front|
|microwave oven, standby||1 foot from sides and top, 1 inch from front|
|media center PC||1 foot from back of case|
|miscellaneous power adapters||1-2 feet|
|fluorescent tube light||3 feet from ballast|
|compact fluorescent light||1 inch from ballast|
|Sleep Number Bed pump, running||2 feet from pump|
|laptop computer (LED backlight), running||2 inches from keyboard|
|LCD computer monitor (fluorescent backlight)||3 inches from center of screen|
|LCD TV (fluorescent backlight)||2 inches from back of case|
|cell phone, standby or making call||1 inch from side facing away from head|
|Bluetooth headset, standby||
1 inch from side facing head
I hope you find this useful! Comments welcome!