Demystifying EMF
Electromagnetic radiation or electromagnetic fields (EMF) are ubiquitous in our environment and onerous to avoid. EMF occur both naturally (e.g., visible light from our sun) and artificially (light from an LED; communication waves for AM/FM radio, smartphones, and Wi-Fi routers; x-rays for medical examinations; gamma-rays emitted from a thermonuclear reaction; etc.). A significant portion of the artificial EMF created is invisible to the human eye — humans cannot “see” it in the traditional sense. But like visible light is to a person affected by blindness, just because we can’t see artificial EMF doesn’t mean it’s not present.
A person who is blind can still feel (physically observe and measure) the warmth of visible light radiation emitted from our sun even though they cannot see it via their eyes. Humans routinely interact with and feel the effects of invisible, natural EMF light every day. We can receive a sunburn from ultraviolet (UV) light or a heat burn from infrared (IR) light even though we can’t see these forms of EMF. Humans are blind to UV and IR EMF as well as any other form of EMF that isn’t visible light. However, our experience with UV and IR demonstrates that even though we cannot see a specific form of EMF, we can still be affected.
Understanding this fundamental concept is critical to comprehending EMF. It increases our awareness that even though one cannot see artificial EMF, we understand that our bodies are still being exposed and that radiation from EMF sources might be affecting us in ways we might not fully understand.
Driven by Moore’s Law and the convergence of advanced wireless communications (e.g., 5G), connected devices, cloud computing, streaming services (e.g., Netflix, Disney+, AppleTV+), declining hardware costs, government priorities, and incentivizing market forces, humankind is constructing a civilization that’s being seamlessly woven together with EMF at a Cambrian rate. The World Health Organization (WHO) issued the following statement:
At this point, and rightfully so, the reader might be confused about what visible light, 5G, Stranger Things, LED light bulbs, and dental x-rays all have in common with EMF? It’s not intuitive and unless you’ve taken a college-level course or two in physics, it can be pretty overwhelming. To summarize, it all has to with the energy particle known as the photon, how nature and humans manipulate or control it, and how it interacts with our bodies.
For the remainder of this discussion, your author will present a high-level explanation of light waves and photons and promises not to perform any math and to only present easy-to-understand equations. Additionally, Rules-of-Thumb will be provided to equip the reader with quick reference guides to understand, assess, and navigate the complex and rapidly changing EMF world we live in.
All forms of electromagnetic radiation or EMF are light waves. Various sources can produce different kinds of light, but they all have the following intrinsic characteristics:
1. Light waves carry at minimum one mass-less energy particle called a photon. This is known as a quantum of energy, or the minimum unit of energy a light wave can carry in a packet.
2. The photon(s) travel at the speed of light in a vacuum, and will not stop until they interact with something else in the universe.
3. The energy, wavelength, and frequency of a light wave are all related.
All the possible types of light waves, or EMF, in the universe exist on a spectrum which is known as the electromagnetic spectrum:
Humans are most familiar with light waves in the ‘visible light’ range, but visible light is only a sliver that shares the same spectrum as the light emitted from other sources such as a Wi-Fi router or an x-ray machine. Signals from a Wi-Fi router are commonly, and correctly, referred to as EMF, but technically visible light is EMF as well — they are all light waves.
Why is it then that we can only see visible light with our eyes and not other forms of light? It’s due to the different frequencies at which a photon is traveling in one light wave compared to another, and the fact that humans have evolved, for survival reasons, an optical sensor that is highly advanced and specifically tuned to the visible light range.
It was quite handy for our ancestors to be able to see a lion via a photon (from the sun) bouncing off the lion and entering our eye. This photon strikes the retina in the back of our eye, and the optic nerve sends a signal to our brain advising that we best take precautionary measures to avoid death. Whereas, being able to see the cosmic microwave background (CMB) radiation wasn’t as useful so natural selection optimized for the former.
A photon gets created as a result of an event in the universe. Such events can occur in nature or be artificially generated. For an example of a natural event, let’s take a look at an (overly) simplified example.
In our sun, under enormous pressure, two hydrogen atoms fuse together to create one helium atom (for brevity, the intermediate steps are omitted). The process is called nuclear fusion, and in the fusion process, a minuscule amount of mass from the original two hydrogen atoms is lost and converted to energy so that the resulting helium atom weighs less than the original mass of the two hydrogen atoms.
The first law of thermodynamics dictates that mass has to be conserved and, in fact, it is. The loss of mass is converted to energy and is released by the helium atom. Ultimately, this fantastic process releases photons in a spherical flux pattern from the sun (picture a balloon getting blown up). These photons will travel through space at the speed of light until they arrive on Earth where they can enter our eye, be absorbed by an object (e.g., dirt, wall, or plant), or bounce off the Earth and continue on their journey in space. The fact that mass is equivalent to energy and can be converted between the two forms was introduced by Einstein in his famous equation:
Photons can be artificially generated as well. For example, Thomas Edison invented the lightbulb which emits visible light and thus photons. By passing an electric current through a particular wire filament, located inside the bulb, electrons are excited in the filament and they release energy in the form of photons. These photons are what we see with our eyes.
Similarly, if we pass current through two ends of, say, a communications antenna (essentially two wires) in an alternating manner, an electric field is created that excites electrons in the wires which causes them to emit photons. These photons, and the light waves they produce are what our smartphones “see” which is precisely the mechanism that enables them to work (send and receive data via light waves).
The difference between the light waves that our eyes sees and that smartphones see is related to the frequency of the photon. When a light wave is created, a photon particle is emitted from a light source that propagates through space with an alternating electric and magnetic field (both in phase) that oscillates like a wave at a specific frequency.
The photon acts both as a wave and a particle, which is known as the wave-particle duality. For more on this topic, reference the short-form videos here and here by the Public Broadcasting Service (PBS).
Rule-of-Thumb #1: To determine what kind of light wave you’re dealing with, simply identify the frequency and look it up on the electromagnetic spectrum (see figure above for scale).
Example #1: A light source emitting photons at 1 MHz (10⁶ Hz) is a radio wave.
Now that we’ve established what light waves are and how photons are created, let’s introduce the elegant equation that allows us to easily determine the energy of any light wave given only its frequency.
This straightforward relationship tells us that the energy of any light wave is equal to its frequency times a constant (Planck’s Constant). This equation also allows us to work backward to determine a photon’s frequency given its energy (just rearrange the variables).
Rule-of-Thumb #2: To change the type of light wave a source emits (if permitted by the device), either increase or decrease the frequency of the wave to slide along the electromagnetic spectrum (see figure below).
Example #2: Increasing the frequency of a light source which emits photons in the IR range will produce visible red light as you slide along the electromagnetic spectrum.
Rule-of-Thumb #3: Wavelength is inversely proportional to the frequency (see figure below). If the frequency increases, then the wavelength decreases and vice versa.
Example #3: The mathematical relationship can be viewed here.
Rule-of-Thumb #4: To determine which light wave has more energy for a single photon, simply look at the frequency — the energy is proportional to frequency. If the frequency of a light wave increases, then the energy increases as well and vice versa.
Example #4: If light wave A is a radio wave and light wave B is an x-ray, then light wave B has higher energy because its frequency is higher.
It’s useful to categorize the electromagnetic spectrum into two categories: ionizing and non-ionizing radiation (light wave/EMF). This distinction matters because ionizing radiation carries enough energy per photon (quantum) to destroy the bonds that hold together human DNA. The WHO provides this explanation:
Rule-of-Thumb #5: Ionizing frequencies are all frequencies above the visible light frequency.
Example #5: Gamma-rays are a form of ionizing radiation, radio waves are non-ionizing.
Below is a non-comprehensive list* of light waves that individuals are routinely exposed to in the United States (U.S.).
AM Radio Broadcasting: 535–1.705 kHz
FM Radio Broadcasting: 88–108 MHz
2G/3G Networks: 850–1900 MHz (AT&T, Verizon)
4G-LTE Networks: 700–2300 MHz (AT&T, Verizon)
Wi-Fi Routers: 2.4/5 GHz
5G** Networks: 30–300 GHz
Visible Light***: 430–770 THz
*Reference the U.S. Frequency Chart for additional details regarding how the radio spectrum is allocated in the U.S.
**5G technology is currently in development and is only being introduced in select regions. It is also referred to as “millimeter wave” technology which refers to the wavelength of light waves with frequencies between 30 and 300 GHz. For more information on 5G/millimeter wave technology, reference the video and article by the Institute of Electrical and Electronics Engineers (IEEE).
***This is not a radio frequency like the others listed. It’s a familiar reference frequency range for comparison.
Inserting the list of frequencies above into the Planck Equation, we can readily rank the photon energy levels of each non-ionizing EMF wave.
The above ranking of non-ionizing EMF is useful, but it doesn’t tell the entire story. To better understand, it’s common to measure how much energy a surface (e.g., a person’s body) is exposed to over a given time. Energy per unit time is power:
Power output by our devices, like a smartphone or Wi-Fi router, can vary. For example, a smartphone that’s connected to a nearby communication tower periodically checks in with that tower to make sure it’s connected. This way it can receive and transmit data on-demand with low latency. This check-in is a digital “handshake” that smartphones and devices routinely make. If a smartphone cannot find a tower, then it might amplify its signal to increase its power to reach and maintain a connection with the tower.
To simplify this concept drastically, assume it takes only one photon per second to connect to a tower, and that the smartphone sends one photon per second in all radial directions equally. If the smartphone cannot connect, it might send two photons per second, then three, then four and so on until it completes the “handshake.” It’s a similar concept to how someone slowly increases the amplitude of their voice when speaking into a microphone “can you hear me?” to confirm the other party can.
Although the above is a gross oversimplification, it’s useful to understand how increasing the number of photons we transmit per second increases the power. If our phone is in our pocket, then increasing power means our body is being exposed to more photons per second, thus more energy per second (higher power).
To continue our example, let’s dig into how photons are emitted from a light source. In the above, we assumed a smartphone emits one photon per second in all radial directions equally. Let’s call it a million photons, each with their own swim lane. Visualizing this as a balloon expanding with the smartphone in the middle, we can see the surface area of the balloon is increasing and thus the photons are passing through the balloon surface with increasing space between them (distance to the nearest photon’s swim lane). The measure of how many photons pass a given surface area per unit time is call intensity or “brightness.” It’s equal to the power divided by the surface area.
Another way to visualize intensity is to image your smartphone is a candle. When you’re close to the candle, the light source is bright. As you walk back the candlelight will dim, the brightness (intensity) will decrease even though the candle didn’t change. Same goes for your smartphone, but instead, the smartphone antenna is the light source. When you’re close to the source it’s bright, the intensity is high, and your body is exposed to a higher amount of energy per unit time per unit surface of your body (on the side that’s facing the smartphone antenna).
Rule-of-Thumb #6: Intensity is inversely proportional to the radius (distance) squared. Light intensity decreases as the radial distance between your body and the light source increases.
Example #6: If you double the radial distance between yourself and a given light source (candle, smartphone, Wi-Fi router, etc.), the intensity decreases by a factor of 4. Triple the distance and the intensity decreases by a factor of 9 and so on.
To reinforce the significance of accounting for power and intensity, let’s compare UV light to microwaves. The UV light has a higher frequency than microwaves and thus the energy of a single UV photon is higher than that of a single microwave photon (Rule-of-Thumb #4). Additionally, UV light is ionizing and microwaves are non-ionizing (Rule-of-Thumb #5). At this point, it would be correct to say a single photon from UV light is more dangerous than a single photon from a microwave. However, as discussed, the energy level doesn’t tell the entire story.
Consider walking outside and remaining in the sun for one minute in full exposure before returning indoors. Next, consider having your hand exposed to the inside of a microwave for one minute. The effect from the former would be negligible while the latter would be severe. This is due to power and intensity. Microwave ovens are specifically engineered to boost the power of microwaves and concentrate their intensity on the contents placed inside. The reason we’re not harmed by these powerful, intense microwaves is that the oven is wrapped (shielded) with a Faraday cage, which blocks all EMF.
The purpose of this article was to provide the reader with a baseline, physics-level understanding of EMF and a reference point to move forward from. Your author hopes this goal has been achieved. If at this point, the reader understands the following concepts, then they should be well-equipped to engage in future EMF discussions:
1. The following terms are synonymous: EMF, electromagnetic radiation, light
2. For all forms of light, the only thing that changes is the frequency of the light wave oscillations. Energy and wavelength are directly related to frequency.
3. Ionizing and non-ionizing radiation are separate categories of EMF delineated by the visible/UV light frequency range.
4. Although the energy of a light wave is important to identify, one must also understand the power (energy per unit time) and intensity/brightness (power per unit surface area) to properly assess.
For those concerned with non-ionizing EMF exposure, below are a few zero-cost techniques to control the EMF sources in our home:
Please see below for additional reference information on EMF:
The WHO maintains a site with comprehensive information relating to their EMF Project.
The American Academy of Dermatology (AAD) lists their guidelines regarding vitamin D and UV light.
The U.S. Federal Communications Commission (FCC) has a page dedicated to answering questions related to Radio Frequency Safety.
Update: The author has published an article titled “IR Saunas and 5G: Comparing EMF Exposure” which pertains to the topics discussed herein.
Demystifying EMF
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