Cell phone, cell towers and other Electromagnetic waves in our lives

Cell phone, cell towers and other Electromagnetic waves in our lives

What are the risks of living next to a new cell tower, or of using your cell phone a lot? Many in the area are asking these questions as new cell towers go up. In response to questions like these from Bob Weingarten, Marti Gross and others, let me give a mini lesson on what is and isn’t known about the interactions between electromagnetic waves and our body’s physiology, and how you might measure your exposure if you wish. And I’ll close with a bit about radon, the greatest radiation risk in our lives and homes.  But first I must review a little physics with you.

Electromagnetic radiation (EMR) consists of waves of energy travelling at the speed of light emitted from a source like the sun, a magnet, or commonly from various machines (eg. flashlight, radio tower, xray machine, computers, TV sets, nuclear bombs). The waves have both a photon and a magnetic component, which oscillate in phase with each other perpendicular to their direction of travel. Both components contain roughly equal amounts of energy measured in Gauss units (more later) and can be transferred to a body, animate or inanimate, directly in their path (line of sight usually but those with long wave lengths like FM radio waves can bend over and around hills too). They can be blocked by some barriers, generally less well the higher frequency they are; generally the higher the frequency the more energy the waves contain, so gamma waves are very difficult to block at all. The energy transferred is primarily heat at frequencies less than ultraviolet light; but at higher frequencies more and more molecular and cellular ionization occurs, knocking molecules and atom parts out of kilter, like pool balls with a “break” shot. And one final important point: the power of the source, exposure time, and distance all make a huge difference to level of exposure.  The first two are obvious and the energy from EM radiation decreases logarithmically as you move away from the source; so, for instance, a 50 Gauss unit exposure next to the sources decreases to 7 Gs 100 ft, away and 1.8 Gs at 200 ft.

All this may seem too mysterious; but look at this table for some EM radiation forms you may recognize. The examples are listed by increasing potential risk.

 

Source

Frequency in Hertz units (cycles/second)

Energy in Gauss units if primarily magnetic

Earth magnetic field (as detected with a compass)

 

0.5 Gauss

Refrigerator magnet

 

50 Gs touching

Radio, FM

100 MHz (VHF)

1 Gs touching

Computer/TV screen

400 MHz (UHF)

20 mGs/hr@4 in

3 mGs@3 ft

Cell phones

2+ GHz

5-10mGs@tight, 0.5 @2in

Microwave oven

3-30 GHz

250mGs@4 in

13mGs@3 ft

Powerlines/cell towers

1-300 GHz

Varies by distance and output

Visible light

10 -100 million GHz

Photons

Ultraviolet light

100 000 million Ghz

Photons

Xrays

Million million GHz

Radiation

Radon

10s of million million GHz

Radiation

Gamma rays

Million billion GHz

Radiation

mGs = milligauss, Gs = gauss, Hz = hertz, KHz=kilohertz, MHz= Megahertz, GHz=Gigahertz. Prefixes: milli= 1/1000, kilo = x1000, Mega =  x1 million, Giga= x1 billion. UHF = ultra high frequency; VHF = very high frequency

The magnetic energy component (measured in Gauss units) of these waves tends to predominate in lower frequency zones and the photon/particle radiation energy (measured as RADs) in higher ionizing frequency sources.  Rads are a measure of ionizing radiation at the source. The average person in the US gets about 400 milliRems of ionizing radiation per year. REMs (Roentgen-equivalent-man) are estimates of the effect of RAD doses in humans.  Low doses of ionizing radiation are something we are well adapted to; humans evolved in the presence of radiation and have well developed mechanisms for repairing cell damage from it.

Non-ionizing radiation is generally thought to be safe. However, as with most things in nature, it’s designation is arbitrary and all EMR carries some ionizing particles down the spectrum, hence the concerns with those designated non-ionizing.  Although most studies find no effect, there are some tantalizing epidemiologic studies that suggest cell phone use tight to one’s head and brain for extended periods (over 1 hr at a time) may be increasing brain glioma cancer rates in those users. Many research studies are pursuing this in rats and people. PET scans show changes in glucose metabolism in the brain just beneath a cell phone after 50 minutes of continuous use. This suggests the EMR may be re-orienting the atoms and molecules in the brain, much like an MRI machine does to generate a medical image. I’ve seen gliomas in 2 young women who were intense cell phone users, for what that’s worth. So, I urge everyone you know to avoid such use; this is especially important now that many people no longer have land lines. It is unclear if in-ear Blue Tooth devices help.

Beyond that, epidemiologic research over 30 year has failed to find cancers or leukemia/lymphomas increases in people living close to high voltage power lines. I couldn’t find a similar study about cell towers, but the risks should be similar since their EMR outputs are on the same order of magnitude.  There are also many anecdotal reports of EMR sensitive individuals, who suffer a variety of subjective discomforts when exposed to low energy radiation. Many companies try to sell ineffective devices with fraudulent protection claims. I doubt there’s much there to worry about. If you are concerned, I’d buy a $30 gaussmeter at Home Depot and measure EMR in milliGauss’s wherever you put your head/body for extended periods of time. If the total is in 100s of thousands, try to increase your distance from the sources; if the total is under a few thousand, you are probably better off worrying about Radon.

Ionizing sources of radiation are a much greater concern. Radon is a colorless, odorless, naturally occurring radionuclide that exists in soils and seeps into the air. Maine has a lot of radon in its rock and soil. It is a breakdown product of natural uranium and radium and emits ionizing radiation (alpha particles) into house basements and well water. The tighter the house is insulated, the more radon accumulates, especially in winter. The danger from radon in water is that it enters the air we breath by our showers and water boiling. Because the concentration of radium that generates radon is highly variable in soils, so is the concentration of radon—two houses side by side can have vastly different levels. You must test your house when you move in and every 5-10 years to protect yourself.  Levels under 2picocuries/L in air and over 4000picoCuries/L in water need attention. Prolonged exposure clearly increases lung cancer rates, even faster if you smoke. Don’t wait until someone gets cancer to test. It costs <$50 to do both air and water. Buildings can be made safe, and all should be tested and remediated if necessary.

General principles to diminish your exposure to any radiation: increase your distance from the source, decrease your exposure time, and block it with effective barriers if it is an ionizing radiation.

Relative Contribution Of Various Sources To The Average Annual Dose

Dan Onion, MD, MPH

Mt Vernon Health Officer

dkonion@gmail.com, 293-2076

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