Introduction to EMFs


This page last updated September 7, 2016.

The topic of EMFs is vast and, unfortunately, rather complicated. I will attempt in this introductory article and the separate articles that I have written on each type of EMF to educate you on the basics, on where each type of EMF occurs, how it affects human health, what we consider to be the safe exposure guidelines for each type, and what we do about them to mitigate their possible influence on your health.

To begin with, all EMFs have an electric field component, the "E" in EMF, and a magnetic field component, the "M" in EMF. They are related but they are not the same.

That includes any EMF you will see me discuss on this website or that you read about in other articles on the Internet. What differentiates them one from another is what frequency they occur at.

It gets a little complicated, but electric fields and magnetic fields are present wherever AC, or alternating current, electricity is present. That could be in the form of electricity on power lines and on wires inside houses (circuits in walls and the cords we plug in). It can also involve radio transmitters, where electricity is sent out into the air as wireless transmissions.

The electric field component and the magnetic field component emit out into the air from power lines, circuits in walls and power cords. These two fields come out of a cord or line or wire at right angles to each other.

The following image, from, shows this three-dimensional configuration where the electric and magnetic fields come off the power line, circuit, cord or wireless transmitter at right angles to each other:

The important thing to know is whether those two fields are synchronous, or coupled, with each other or not. If they are coupled, then they rise and fall together. If you have one, you have the other. If you measure one, you can calculate the other.

However, for electricity in certain frequencies, you can have the opposite condition where they are not coupled. In that case, you can have one but not the other. You can measure one type of EMF and think you have measured all EMFs, but if you don’t have a meter to measure the other type of EMF, it could be present, harming your cells, without you knowing it.

The point at which electric and magnetic fields become coupled is when you are within what is known as the far field. That is the distance that three or more wavelengths of the particular frequency travel out from the source, be it a wire or a radio transmitter. This can be seen in the following image, from Wikipedia's article on Near and Far Fields:

Within the near field, however, the electric and the magnetic field components are completely uncoupled and can be separate from one another. You need separate meters to measure each one.

Now, let's review the wavelengths for the four common types of EMFs that people encounter in their daily lives. The first two are from house wiring and power lines from the electric utility. Those would be the AC electric fields from house wiring, and AC magnetic fields from house wiring. Those are our first and second types of EMFs among the four that we recognize.

The reason they are considered separately is because the frequency that electricity on house wiring and on power lines, which is the same thing, oscillates at is 60 Hz (Hertz), or 60 cycles per second. That frequency has an astonishingly huge wavelength for one wave of 3,100 miles! That means that the distance that the electric field component and the magnetic field component of 60 Hz electricity emanating off a wire takes to complete one wave is the distance from California to New York. Assuming it starts at the zero crossing point in California, that wave is not cresting to the upward pointing peak of the sine wave until it reaches Denver, and it isn't dipping below the zero crossing point until it reaches the Midwest. Obviously the strength of the field dissipates within a few to several feet from the wire, but the shape of the sine wave does not change much at all over many miles. Three times that distance, to get you into the far field, would then be the circumference of the entire earth.

Thus, for all practical purposes, with house wiring and the electricity from power lines (same thing), we never get into the far field.

That means, when we measure the "EMFs" from house wiring and from power lines, if we use only a Gauss meter and see that the level is low, or it is high and we make it low (if we can), that does not mean we have identified and removed all EMFs. We have only identified and dealt with the "M" of the EMF, the magnetic field. Click on the link for my Article on Magnetic Fields, accessed from my Articles on EMFs page here, to read a detailed description of their cause, their health effects, and how we mitigate them.

We still have the "E" of the EMF to deal with, and that is the AC electric field. This field comes off unshielded, plastic-jacketed Romex electric circuits in walls and floors and plastic jacketed AC power cords that we plug in, extending into a room up to six to eight feet from walls and from those cords. They rob you of a good night’s sleep and drain your energy when you put your hands on a keyboard of a computer that has an ungrounded plug. I explain the identification and mitigation of electric fields in my Article on Electric Fields on my website, accessed from the Articles on EMFs page here.

The third type of EMF is radio frequencies. They are produced close to our body and in our homes from the transmitters in wireless devices, such as cell phones, tablets, laptops, routers, and cordless telephone handsets and their base units. Wireless frequencies enter our homes from outside sources such as smart meters, cell antennas, airport radar, and radio and television broadcast towers.

One potential health effect from radio frequencies comes from long term, close range exposure to the the heating effect of the carrier wave in the microwave frequency at 700 MHz (MegaHertz), 800 MHz, 900 MHz, 1,800 MHz, 1,900 MHz, and 2,400 MHz and 5,800 MHz. These are the frequencies that the FCC has given to industry to use for unlicensed low power transmitters that we use in our every day lives. This means, you don’t need an FCC license to operate a radio transmitter in the form of your cordless telephone base unit and handset or your router and laptop in your house.

These last two frequencies are also known as 2.4 GHz (GigaHertz) and 5.8 GHz. They are the predominant frequencies of Wi-Fi. Smart meters typically use 900MHz to broadcast their beacon signal and their data, and they will use 2.4 GHz for the Zigbee Home Area Network (HAN) that will be activated at some point on most smart meters, allowing them to communicate with your appliances in your kitchen and laundry room.

In the frequency range used by wireless transmitters, the wavelength of the sine wave for one wave is within the human dimension. At 900 MHz, the wavelength for one wave is 13 inches. For Wi-Fi at 2.4 GHz, the wavelength is 5 inches. Thus, the far field for a smart meter transmitting its Neighborhood Area Network (NAN) beacon signal and data signal begins roughly three times the wavelength, which would be three times 13 inches, or roughly three feet from the smart meter.

Thus, we recommend that anyone measuring smart meters with the radio frequency detectors that most people typically use take their measurements at three feet and beyond for accuracy. This is because the electric field portion and the magnetic field portion of the transmission have not coalesced into a stable wave until they reach three wavelengths, or the far field.

One important distinction when measuring radio freqeuncy EMFs is that we do not measure magnetic nor electric fields separately, because they are all coupled (when we are in the far field). Instead, we measure what is known as the power flux density, or PFD. That is measured in milliWatts per centimeter squared, or mW/cm2, as the FCC does, or in microWatts per meter squared, or µW/m2, as we and countries outside the US do. This is discussed in detail in the section, The FCC Versus the Rest of the World, in my Article on Radio Frequency EMFs, accessed from my Articles on EMFs page here.

Considering that all of our radio frequency detectors come with far field meters as standard equipment, we need to not pay attention to readings we get within the near field. So measure smart meters at three feet and beyond, if the primary frequency is at 900 MHz, which most of them are. When measuring Wi-Fi transmitters (routers, laptops, tablets), you can get as close as 15 inches and still get accurate readings. Within that distance, however, you are within the near field and your numbers will not be accurate.

You can purchase near field antennas for some radio frequency detectors, if you want to measure the actual reading close to the source. However, to us, it doesn’t really matter so much how high these numbers go when we are showing them to clients, because they are all way too high for human health. Whether you smoke half a pack of cigarettes a day or two packs, it doesn’t matter. It’s all cigarettes. Everyone needs to go to hardwired alternatives to wireless devices as much as possible.

The fourth type of EMF, so-called "dirty electricity" (DE), is generally defined as the harmonic frequencies in the 2,000 to 100,000 Hz range, or 2 kHz (kiloHertz) to 100 kHz. These are produced by dimmer switches, by the switched mode power supply transformers found in the bases of compact fluorescent lamps (CFLs) and LEDs, and by variable speed motors, such as new energy-efficient furnaces, among other devices. Photo voltaic (PV) solar panel inverters also create dirty electricity as a by-product of stepping low voltage DC (direct current) electricity produced by the panels up to 120 Volt AC (alternating current) electricity for use by the grid.

Smart electric meters have switched mode power supplies to step down the 120 Volts that enter them to power the circuit boards that they contain, and hence also create dirty electricity (although some brands, notably Itron, appear to have filters that prevent DE from emerging onto circuits into the house, according to studies I have conducted of Itron smart meters in Southern California).

Dirty electricity frequencies have a fundamental frequency and harmonics of that frequency. The strength of each succeeding harmonic decreases as the frequency of the harmonics gets higher or faster. The fundamental frequency and its harmonics are carried as additional, faster frequencies that literally ride on top of the 60 Hz sine wave of AC electricity in circuits, plastic cords and outside power lines. They can be seen with an oscilloscope and spectrum analyzer as faster frequencies superimposed upon the slower 60 Hz sine wave of electricity produced by the power company.

The electric field component and the magnetic field component of dirty electricity harmonic frequencies both emit off circuits, cords and power lines into the room and outdoor air, and they affect our health. Some people are particularly sensitive to them. Dirty electricity is discussed in more detail in my article on Dirty Electricity EMFs, accessed from Articles on EMFs here.

We generally only measure the electric field component of dirty electricity when we use a Stetzer or Greenware microsurge meter. The units displayed on these two meters are variations of electric field strengths. To measure the magnetic field component, which is also there, one must use an oscilloscope and spectrum analyzer.

One of my building biology colleagues, Michael Schwaebe in Encinitas, California north of San Diego, is doing extensive research on dirty electricity and the meters and filters we use to measure and mitigate it. He is discovering some surprising findings that are not what we had expected. His research is discussed in his talk at the building biology conference in Seattle, held in July 2015. That talk, along with other presentations given at that conference, are available from the building biology website on the Conference Videos page here.

Thus, we have four types of EMFs, each with their own frequency. All have electric and magnetic field components. These are measured differently, with separate meters, such as from house wiring and electric power lines. The EMFs from wireless transmitters are measured as a composite number, the power flux density. Dirty electricity is typically measured with a plug-in meter that measures the electric field component of the dirty electricity within the range of each meter.

I realize this is all quite confusing, but those of who are really interested in mastering and understanding EMFs need to re-read the information presented above, as well as similar articles by others on this topic, several times over several sittings.

Once you understand the basics, you can then understand more easily how each type of EMF differs from the others and how you and we measure and mitigate them. Follow the links to the separate articles that I have written on each type of EMF, again accessed from the Articles on EMFs page here.

Hopefully this introduction will make it somewhat easier for you to understand what you read in those separate articles.

To return to the main Articles on EMFs page, click here.

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