Get Smart about Energy™


by Bob Spofford – Energy Chair, Sustainable San Rafael

An electromagnetic field exists any time electrons are in motion. If those electrons move back and forth in a regular manner (i.e. oscillate) they create electromagnetic waves that propagate through space at the speed of light (which isn’t surprising, since light is an electromagnetic wave.) Man didn’t invent electromagnetic radiation. It pours out of every star - - not just as visible light, but in a very wide range from radio frequencies (thus radio astronomy) and all the way up beyond visible light to X-rays and gamma rays. This is important, because it means that humans evolved in an environment that included a lot of electromagnetic radiation (from the sun) and that we are adapted to certain kinds of radiation hitting us and passing through us with no harm.

That brings us to the spectrum. Every electromagnetic wave has a frequency, which is the speed, in cycles per second (aka Hertz, “Hz”) at which the electrons creating that wave are vibrating back and forth.

Here’s a picture of the complete spectrum of electromagnetic radiation

Because all these waves are traveling at a constant speed (the speed of light), each frequency translates to a specific wavelength, which is the physical distance from one peak of the wave to the next one. The higher the frequency, the shorter the wavelength and vice verse.

The lowest frequency used for any normal kind of radio signaling is around 30,000 Hz, which means a wavelength of 10,000 meters – over 6 miles. The highest communication frequency in use is up around 300 GHz (300 thousand million cycles per second) with a wavelength of about 1 millimeter (.04 inch.)

Why is this important? The wavelength of a signal determines how it interacts with something it hits as it travels through space. The range above (6 miles to .04 inch) represents the limits within which we can build an efficient receiving antenna, in which electrons can vibrate back and forth in response to the incoming waves.

However, electromagnetic radiation goes up to far shorter wavelengths. When you get up to X-rays and gamma rays, the wavelength is so short that it’s more practical to treat them as beams of particles. Visible light is interesting in that it’s at a wavelength where it acts as both a wave and a particle, and understanding this laid the foundations for a lot of modern physics (but we don’t want to go there.)

There’s one more key dimension to any electromagnetic radiation, and that’s its signal strength or power. This is a measure of a signal’s ability to make something happen . . . to do work. It’s expressed in lots of ways, often watts per square meter or microwatts per square centimeter, but the important thing is that it declines with the square of the distance from the source. This is known as the inverse square law, and it dates back to Isaac Newton. So, say your laptop is sitting one foot from your WiFi router, and it’s receiving a signal strength of 1.0 (the units don’t matter.) If you now move it two feet away from the router (double the distance) the signal it receives drops by a factor of 4 to a strength of 0.25. And if you were to move it 10 feet away, the signal strength would be just 1% of what you had back at one foot.

The inverse square law becomes a key factor in evaluating possible danger from signals. For example the low-band TV stations on the Mt. Sutro tower (channels 2, 4 and 5) each transmit with a power of 1 million watts (They’re aimed out toward the horizon, so the people near the tower are not blasted with anything like that.) Out here in San Rafael, 15 miles away, the inverse square law means that the power from one of those stations is down to around 0.003 watts, not something to worry about.

So, enough with the physics, what’s the health story?

There are two clearly-recognized heath issues with electromagnetic radiation. These have been studied at great length since the 1930s.

The first is ionizing radiation. This is where very short wavelength waves are able to knock electrons off of molecules creating ions (charged molecules.) These in turn can cause all sorts of nasty biological effects. The lowest frequency that can cause ionization is ultraviolet, which can result in sunburn and skin cancer. They go up from there through X-rays, gamma rays and the particles from radioactive decay, all of which can cause burns, radiation sickness, cancer and more.

The key thing is that these are all in the realm of particle-type behavior, and the key factor is that the particles have to have an energy of a few electron volts (or more) to cause damage. Below this energy level they are harmless. This has to do with quantum effects and the ability to knock electrons loose.

This is where a lot of misunderstanding occurs about cumulative exposure. If you are exposed to ionizing radiation, you may not notice any effects at first, but small amounts of cell damage build up over time until cancer or some other awful effect appears. That’s why safety measures around X-ray machines and nuclear plants are mainly based on limiting cumulative exposure.

Conversely, if the energy level of radiation is below the ionization threshold, it doesn’t cause any damage, cumulative or otherwise. You can be exposed to it for a long long time, and nothing will happen. For example, a fluorescent bulb gives off a small amount of UV radiation, but the energy of those waves/particles is very low. You could stand under that bulb a lifetime and not get a sunburn, let alone skin cancer. (Again, this is because ionization is fundamentally a quantum phenomenon.)

The second health issue is dielectric heating. Many molecules, including water, are electric dipoles, meaning they have a positive charge on one end and a negative one on the other. In the presence of an electromagnetic wave, they try to twist one way and then the other as the positive and negative waves pass by. If those waves are powerful enough, the water molecules actually spin at a high rate of speed creating a lot of heat. Thus, in a microwave oven your coffee gets hot and your broccoli steams.

This takes a lot of power. A typical home microwave delivers about 700 watts of electromagnetic energy to the cooking space. There’s nothing magic about a particular frequency when it comes to this type of heating. Home microwaves have standardized on 2.45 gigahertz because several of the electronic components have to be built for a specific frequency. Some large industrial microwave ovens use a lower frequency near the very bottom of the microwave range. In fact, any frequency can cause this kind of heating with enough power behind it. If a tower worker at Mt. Sutro accidentally climbed in front of the antenna when one of those million-watt TV channels was on the air, he could get cooked to death (it has happened.)

However, it’s important to understand that this heating hazard has nothing to do with ionizing radiation. The wavelength of the radiation in a home microwave is around five inches. This is gigantic compared to any kind of molecule. Trying to knock an electron off a molecule with a 5-inch wave would be like trying to pick a lock with the Goodyear blimp.

Historically, science didn’t worry about cumulative exposure to radio heating. Nobody would hang around in radiation strong enough to burn you, and all the other radiation in the environment was at very low levels, like the .003 watt TV signal in San Rafael.

Then came the cell phone. Suddenly, millions of people were walking around with a transmitting antenna up against the side of their head. The early cell phones put out as much as 3.6 watts. Modern ones are mostly 1 watt or under. They operate at frequencies in the low to mid microwave band (mainly 800GHz and 1900 GHz.)

It wasn’t long before anecdotal reports of health symptoms started to pop up, and simple physics said that a cell phone transmitting by your ear would produce a very, very small heating effect in the brain near the ear. Some serious scientists hypothesized that very long-term exposure to this micro-heating effect could produce some kind of cellular damage or other health effect, and studies were launched to see.

Many such studies have been conducted over the years, and the results have been ambiguous at best. True believers on both sides are convinced the research supports their view. (And, that the studies which support the other side are fatally flawed.) You can spend weeks on the internet reading these studies and still not find a clear conclusion. My personal view is that if there were any serious health effects, they would have jumped out of this research somewhere. We’ve been using these phones for over 20 years, and several billion people is a pretty good sample size. If there’s anything to worry about, I think we would have seen it in things like public heath statistics on brain cancer or hearing loss or something, and we haven’t. (The National Cancer Institute, part of US NIH, reports that the rate of all brain cancers actually decreased between 1990 and 2002, from 7.0 to 6.4 cases per 100,000 persons. ) However, I accept that some science-respecting people believe otherwise.

The reason for the focus on cell phones is that the radio transmitter in a smart meter is quite similar to a cell phone. It operates on 900 MHz at a power of 1 watt or less. On the other hand, it is usually much, much farther away from your brain. A 1-watt cell phone 1 inch from your brain would is 1,296 times stronger than a 1 watt smart meter 3 feet away (and it’s 14,400 times stronger than one 10 feet away and 57,600 time stronger than one 20 feet away.) This is the inverse square law in action.

Back in 2005, as they were gearing up for the smart meter launch, PG&E hired two widely-respected experts on RF energy – Richard A. Tell and J. Michael Silva – to analyze the potential RF exposure from the meters. These are available at The following table shows examples of RF Fields Commonly Found in the Everyday Environment in Relation to SmartMeter™ System Operation.

That’s pretty much where established science leaves off and speculative theories begin. The people opposed to smart meters haven’t been arguing that the danger is recognized things like ionizing radiation or tissue heating. Rather, a lot of them express a sort of generalized fear that there’s just “too much radiation” in our environment, and the smart meter is one more log - - perhaps one log too many - - on the fire. They fear that some day we’ll discover a health problem from the cumulative affect of all this low level radiation around us.

I have several problems with this line of thinking:

1. If there is something going on, the big culprit will have to be the cell phone, since the radiation exposure there is so much higher than all the other sources. Compared to cell phones, the smart meter isn’t a “log” on the fire, it’s more like a broom straw. So we should keep looking at the cell phone research, but in 20+ years, not much to be worried about has emerged.

2. They don’t really propose a mechanism by which this unspecified damage might occur, so they can’t tell us what facts would change their mind. This makes it well-neigh impossible for the PUC or any other fact-based body to say “here’s the proof you want that these things are safe.”

3. They keep coming back to the possibility of cumulative exposure to a number of low level radiation sources, and drawing parallels to things like cigarettes, which people once were told were safe. However, cigarettes and other cumulative risks are like ionizing radiation. There are chemicals in cigarette smoke that damage cells from the first exposure, and that damage then accumulates with repeated exposure until symptoms appear. Plus, the epidemiological connection between smoking and cancer was crystal-clear as soon as people started looking at the statistics.

We’ve been working with radio waves for over 100 years, and we’ve been walking around in them since the dawn of time, and we haven’t discovered any such pernicious effect from the kind of waves coming off the smart meters.

Beyond the cumulative exposure worries, there are people advancing a bunch of ideas that are just pure speculation (to use the polite word.) Their common thread is that there is something unique about the radiation from a smart meter – because it is attached to house wiring or transmits in pulses – that makes it a much greater health threat than other devices radiating at the same frequency and power. (Fact check: computer WiFi, garage door openers and modern cordless phones all use the same frequencies and pulsed signal structure.)

These claims of unique dangers are posited in very sketchy terms by writers who seem to have little understanding of the underlying science, so I have to guess at the supposed basis for them. As best I can determine, they seem to be borrowing – and misunderstanding – little snippets from ionizing radiation, the propagation of electrical noise and the mathematics of square waves. Until I see a more complete explanation for one of these theories that makes sense in terms of known science, I have to treat them as wishful thinking. However, the proponents are quite certain that their wishful “theory” alone is grounds to reject smart meters entirely.

My understanding of the Precautionary Principle is different. We can’t “prove” that anything is absolutely safe. That would require certainty of an absence of something, which no one can deliver. (There’s probably a long word for that in Philosophy courses.) The precautionary principle requires that if someone can advance plausible, specific reasons why a product might be harmful, we should hold back until we meet some reasonable level of proof that this isn’t the case. My interpretation of “plausible” in this context means that the feared threat, even if highly improbable, is at least consistent with known science. Otherwise, I could propose banning cotton clothing based on my personal theory that wearing cotton for 40 to 50 years makes your gut grow, your hair turn gray and your eyes go bad. (After all, there’s certainly a correlation.)

So far, the claims I’ve seen that the radiation from a smart meter is somehow “special” do not pass this test.

So, my net takeaway on the health issue is, yes, there’s always the distant possibility that some solid evidence connecting cell phones and health risks will emerge even after all these years. However, even if that happened, we’d have to question whether devices like smart meters, with thousands of times less radiation exposure than phones, are a danger.


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