Say goodbye to your cables, because wireless charging is quickly becoming ubiquitous. But there are many unanswered questions around wireless charging and EMF. Are wireless chargers safe? How do they work, and how much radiation"Radiation" in the context of Electromagnetic Fields (EMF) refers to the process by which energy is emitted and transmitted through space or a material medium in the form of electromagnetic... More do they emit? That’s what we’re going to explore in this post.
How Wireless Charging Works
Wireless charging lets you charge devices without having to plug them in to any cables.
For wireless charging to work, you generally need two elements: a transmitter (like a charging pad or a stand) that’s connected to a power"Power" in a scientific context refers to the rate at which work is done or energy is transferred. In simpler terms, it's how fast something is using energy. For example,... More outlet, and a receiver (built into a phone or phone case, for example). The idea is that you just need to sit your device on top of the charging station and – voila! – the battery will automatically start to recharge.
While smartphones and tablets immediately spring to mind, they’re far from being the only devices that use this technology. Wireless charging has been or is being developed for kitchen appliances, power tools, medical devices (like implants), vehicles, drones, and much more.
So how does wireless charging work? Let’s look at that first, in simple terms, as it’ll help us navigate the question of whether wireless charging is safe.
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Inductive vs Resonant Charging
Up until recently, most wireless charging has been based on the process of induction. This is known as inductive charging.
With inductive charging, a transmitter coil in the charging base station connects to a receiver coil in the device. The electrons inside the transmitter coil flow around inside it, generating a magnetic fieldIn the context of electromagnetic fields (EMF), the term "field" refers to a region in space where electric and magnetic forces are exerted. An electromagnetic field is generated by electrically... More (this is known as electromagnetic induction). This magnetic field causes electrons to flow around in the receiver coil, generating the electricity that charges the device’s battery.
Inductive charging only works when there’s direct (or nearly direct) contact and correct alignment between the charging pad and the device.
A variation of this is called resonant charging. The basic technique of induction is much the same, but resonant power transfer uses a more complex design to tunnel energy"Energy" is a fundamental concept in physics, often described as the ability to do work or cause change. In everyday terms, it's what is needed to move things, heat them... More from one coil to another (this type uses magnetic resonance). The upshot of this is that the device and charging pad don’t need to be so closely coupled (i.e., they don’t need to be touching), as the power can be transmitted across a greater distance.
Resonant charging uses a higher frequency"Frequency" in the context of electricity, Electromagnetic Fields (EMF), and wireless communication, can be thought of as the number of times something happens in a second. Specifically, it refers to... More (around 6.78MHz, while inductive charging uses a low frequency of 112kHz to 250kHz).
Radiofrequency Wireless Charging
Though the inductive types of wireless charging are the ones you’ve probably heard about the most, there’s another emerging type: RF (or radiofrequency) wireless charging.
This next generation of wireless charging tech uses radio waves instead of induction to charge devices. This means the device can charge from a much greater distance from the transmitter, with no line of sight needed. Using RF waves means these types of transmitters are always on and always transmitting EMF radiation across larger distances and through walls and other objects.
There are two main types of RF wireless charging: near-field and far-field. Imagine far-field as being like a WiFi router. It beams a signal all around and if you’re close enough to it, your device can pick up the signal and start charging. A downside of this is that there’s a lot of power fall-off with distance, so charging is not efficient. Near-field works better but you need the device to be closer (think of a box or drawer that you drop your device into so it can charge).
Different Wireless Charging Standards
These different types of wireless power are relevant to consumers because they form the basis of the main wireless charging standards that the majority of the tech is built on.
The standard you’ve most likely heard of is Qi (pronounced “chee”).
Qi is an evolving standard developed by The Wireless Power Consortium. It’s backed by hundreds of big-name companies including Apple, Philips, Samsung and Google. Qi is specific to mobile computing devices (the consortium has other, higher-power standards for other types of devices) and uses inductive charging in the range of 5-15 watts.
The other major standard you might hear about is AirFuel, formerly known as Rezence. The AirFuel Alliance are continuing to develop both resonant and radiofrequency wireless charging (called AirFuel Resonant and AirFuel RF respectively). These both use a higher power transmission frequency than Qi and can charge multiple devices at the same time.
Emerging wireless power platforms you may hear about such as Energous WattUp and Humavox ETERNA are built based on the AirFuel RF standard.
Wireless Charging Safety
So now you have a bit of background on what wireless charging is and how it works. The next big question is naturally, is it safe?
The short answer is, we don’t know. Because, as is generally the case with new types of wireless tech (case in point: 5G), there’s been no real testing into the health effects – especially long term.
If we get to the crux of it, though, here’s what you should be aware of. All types of wireless charging create an electromagnetic field (EMF). And if we look at the compelling body of research into the effects of EMF, it’s growing increasingly clear that EMF radiation is not safe.
Since wireless charging presents yet another type of EMF radiation that we’re exposing ourselves to, its safety is most certainly in doubt.
The Unknown Health Risks of Wireless Charging
Here’s the thing. We are increasingly surrounded by radiation from wireless devices everywhere we go, and at every moment in our lives. That’s a trend that keeps on continuing, and has already led many (including the World Health Organization) to issue warnings about the risks to human health.
The shift to wireless power, however, represents an order-of-magnitude leap in the amount of EMF radiation that inundates our bodies.
Wireless charging has already been rolled out across various coffee chains and restaurants, including various Starbucks locations and hundreds of McDonalds restaurants in 17 countries. It’s being designed into new car models. Apple’s Airpods Pro already come with wireless charging, as do Samsung’s latest Galaxy earbuds. In fact, the Wireless Power Consortium says that the number of Qi-enabled devices being shipped out daily already surpassed 1 million back in 2018.
It’s yet another EMF-emitting technology being released to the market without any testing whatsoever on its real risks to human health. As Engadget wrote in an article about Haier incorporating wireless charging into home appliances like dishwashers:
“Wireless charging is a little bit more convenient than plugging your device in, but was picking up a microUSB lead ever that much of a chore in the first place?…Then there’s the question of if it wouldn’t be damaging to health in the same way that people have raised concerns about living next to electrical substations?”
It’s a valid question. Especially with the ramping up of the Internet of Things (IoT) leading to a multiplication of internet-enabled devices. Now imagine if all of those were charging wirelessly as well. That’s an unprecedented level of EMF in our environment.
How Much Radiation is Emitted by Wireless Chargers?
One point often made by the wireless charging consortiums and developers is that the frequency and power of wireless chargers is very low. This is mostly true, especially of the Qi standard.
Here’s a statement from the website of the largest supplier of Qi-compatible wireless chargers, Powermat, who already have 12,000 Charging Spots, 3.2 million cars and over 500 million smartphones all using their technology:
The electromagnetic field created by a wireless charger is insignificantly little, no more than a home or office WiFi network. Rest assured that you can safely wirelessly charge your mobile device on your night stand and on your office desk.
The problem with this statement is that your home or office WiFi network is far from safe. Take a recent study out of Japan, for example, which found that exposing human sperm to WiFi for just two hours significantly increased their death rate and lowered their motility. Or that pregnant women exposed to higher rates of EMF radiation from cell phones and WiFi have triple the miscarriage rates.
Comparing wireless charging to WiFi as an argument for its safety? Hardly compelling.
And that’s not to mention the countless other diseases and negative health effects caused by EMF exposure.
On top of that, the radiation from wireless chargers is in addition to all the other EMF bouncing around in your home and office. So the effects are cumulative.
All of this said, the different standards and the products that use them are not all equal. Some emit stronger and higher frequency radiation than others. Let’s see how they test in the real world.
The Difference Between Qi and Resonant EMF Levels
At a past edition of CES (Consumer Electronics Show) in Las Vegas, I had the opportunity to measure chargers using both the Qi and Airfuel Resonant (then Rezence) standards. What I found were big differences in emissions from these two technologies.
The wireless chargers I measured in 2016 based on the Qi standard emitted, at max, 3 milligauss (mG). And when no phone was touching the charger, the emissions were effectively 0 (meaning, when nothing was being charged, the charger emitted nothing, which is a great feature). I measured multiple devices based on the Qi standard, from different manufacturers, and found the same results. And, as expected, the power of those emissions diminished significantly with distance. A few inches away, and you’re already under 1mG.
Then I measured emissions from Resonant chargers, and the results were far more concerning. In stark contrast to the Qi chargers, the chargers I measured using resonant technology emitted at least 100 mG. I say ‘at least’ because 100 mG is the max measurement on the Trifield meter I brought with me.
Even more troubling, I measured that same reading whether any devices were charging or not. In other words, the wireless chargers I measured based on the Resonant standard emitted at least 100 mG all the time, whether or not they were actually charging anything.
100 mG is 100x the maximum exposure recommended by the BioInitiative Working Group. So, these Resonant chargers were emitting 2 orders of magnitude above the exposure recommended by this group of international scientists based on their review of thousands of peer-reviewed scientific studies. It really is a massive level of EMF emissions in the ELF (extremely low frequencyDefinition and Characteristics Extremely Low Frequency (ELF) refers to the lower end of the electromagnetic (EM) spectrum with frequencies from 3 Hz to 300 Hz. This range lies below the... More) range of the spectrum.
I did reach out to both Qi and Airfuel Resonant (then Rezence). The latter did not reply. In contrast, Qi replied that their lower emissions are intentional, the product of their superior engineering, a fact that they attempt to explain in greater detail in this post.
While I believe any additional EMF exposures are of potential concern (precisely because they are additive to all the other exposures we already have from our phones, WiFi, smart meters, cell towers and so forth), my tests clearly showed a massive difference between the risks of these two standards.
Now, it’s also worth noting here that the technology has evolved since I did those tests. And as yet I’ve not been able to test any RF-based wireless chargers. But it’s worth noting that the EMF radiation levels of this technology was already at concerning levels in earlier generations – and since the developers are on a constant quest to make wireless power work from greater distances, it’s likely that the EMF levels have increased rather than diminished.
Qi Charger Emissions Update – 2020
I returned to CES in 2020– four years after my initial tests– and had the opportunity to take additional measurements. This time around, the Qi chargers emitted notably higher levels of EMF radiation.
First, let’s take a look at a wireless charger from a company called AirCharge, which builds their technology on the Qi standard. Take a look at what I measured.
Right up against the charger, you can see that the TriField measured ELF-magnetic fields between 50 mG all the way up in excess of 100 mG! (That’s what it means when the TriField reads ‘1 —-‘ – it means that the readings exceed 100 mG, which is the max that the TriField can measure.) That’s simply massive.
As this was 2020 (four years after my initial tests), and technology continues to evolve, the Qi technology is now available in additional products. Here’s a video I took of measurements of a device called a Charterhouse, which is a wireless kitchen cooktop.
As you can see in that video, even about a foot away, I was measuring over 5 mG (milligauss)! That’s huge for being so far away. Then, as I got closer, you can see the levels exceed 20 mG! That’s approximately 10 to 20 times the level of low frequency magnetic power than a standard charger plugged into a wall.
This time I switched my meter to measure radio frequencyRadio Frequency (or RF), a subset of EMF, encompasses electromagnetic wave frequencies ranging from about 3 kilohertz (kHz) to 300 gigahertz (GHz). These frequencies are extensively used in modern wireless... More (RF) emissions. I figured the readings would be quite low, since in my prior testing wireless chargers were a significant source of ELF radiation, but not radio frequency (which is the type of EMF used for wireless communication). It turns out I was mistaken.
You can see that a foot away, it’s already reading over 4 mW/m2 (milliwatts per square meter). That’s about what you could expect to read directly from a cell phone that’s making a call. But remember: in this video, that’s about a foot away. And as I got closer, the levels exceeded 16 mW/m2! That’s like four cell phones running at high power.
So, in the four years between 2016 and 2020, it appears that manufacturers implementing the Qi wireless charging standard have been building devices that emit even more EMF radiation, not less. And it’s a vivid illustration of how weak our EMF safety standards are, and how little manufacturers consider EMF emissions in their product design.
Is iPhone Wireless Charging Safe?
Given the prevalence of Apple products in the smartphone market, a lot of people specifically ask the question, how safe is wireless charging on the iPhone? So we’ll address that here.
If you have an iPhone 8 or later, it has inbuilt Qi charging functionality.
Apple as yet have not embraced radiofrequency (RF) charging. This means that to charge your iPhone, you need a Qi-certified transmitter (like a charging pad) to directly sit your phone on top of.
There’s a disadvantage to this. You can’t pick up and use your phone while it’s charging as it has to stay touching the dock. No doubt Apple, like other manufacturers, will want to get around this. And it seems logical that the more far-reaching RF-based power will be the future solution.
So for now, iPhones and other devices using the Qi standard are emitting a relatively low amount of EMF (though remember, as noted above, there’s a huge volume of studies demonstrating that no level of EMF is “safe”).
And it’s a compounding problem.
It might be tempting to think of a cell phone or smart phone as a single source of EMF. But that’s not accurate. The iPhone already includes cell phone connectivity, WiFi, BluetoothFrom the perspective of someone concerned about the health effects of electromagnetic radiation, understanding Bluetooth radiation is crucial, especially in our increasingly wireless world. Bluetooth technology, ubiquitous in our daily... More and NFC wireless connectivity (to support functionality like Apple Pay). That’s four separate sources of EMF radiation.
On top of that, Apple already did away with the headphone jack on its iPhones, opting instead to encourage iPhone users to use their wireless AirPods. So that’s a fifth source of EMF radiation from a single iPhone device – and one that channels right into your ear canal, which is just inches away from your brain, without any bone to act as a natural EMF shield.
The introduction of wireless charging adds a sixth separate source of EMF radiation exposure for its customers. And, in fact, it’s not clear what type of regulations or testing (if any) these wireless chargers will be subjected to.
With each additional source of EMF radiation in these industry-leading smartphones, Apple is increasing their customers’ exposure to additional sources of radiation that the World Health Organization designates as a Class 2B Carcinogen.
Wireless Charging and Electric Vehicles: Charge As You Drive
Electric vehicles (EVs), as you may know, don’t have an internal combustion engine. Instead, they contain a large traction battery pack to power the motor. You can charge these batteries by plugging them into a wall outlet, also known as electric vehicle supply equipment or EVSE.
Today, an individual may choose to drive an EV for two reasons. Right now, the cost is not one of them: Since EVs are currently in their development phase, the cost is higher than vehicles with combustion engines. So what are those reasons?
Less pollution: When you choose to drive an electric vehicle, you save one more vehicle exhaust from polluting the air, which in turn helps the environment. Although, these vehicles still create greenhouse gas when you charge them from an electronic grid. But despite this, EVs are a lot better for our environment than traditional motor vehicles.
Renewable energy: This is the second leading reason why people drive EVs. Fuels like diesel and petrol are non-renewable. And even CNGs (compressed natural gas) and LNG (liquified natural gas) are finite. So, instead of using up all the natural resources, the better option is to switch to renewable energy, like the sun.
For EVs, you can install a solar PV (photovoltaic system) system in your home. This way, you can charge your vehicle without worrying about massive greenhouse gas emissions.
Experts predict that EVs and other zero-emissions vehicles will account for 70% of new vehicle sales by 2040. And this is excellent news for our extremely polluted atmosphere.
The Problem with Current EV Charging Methods
As of January 2021, there’s an estimated 150,274 convenience stores in the United States. And 81% of these stores sell motor fuel, says NACS.
Since EVs are relatively modern, there aren’t many EVSE ports available where you can go and recharge your car. You have to make sure to charge your vehicle overnight to be able to drive tomorrow.
But as the popularity of electric vehicles increases, the chances are that most gas stations and convenience stores will install these ports. And therein lies the problem.
EVs, even with a level 2 charger, take at least 3 hours to charge. So, while you could be ‘in and out in less than 15 minutes with a gas-fueled car, you can’t do the same with EVs. And it’s highly unlikely that most people will have the time to sit in a convenience store or a gas station for three hours. So, engineers are moving towards a more efficient solution: concrete pavements that charge your vehicle as you drive it.
The Solution
To make this vision a reality, brilliant minds from the Indiana Department of Transportation (INDOT), German startup Magment GmbH, and Purdue University’s engineering team came together to create a system that wirelessly charges electric vehicles as you drive.
Their idea is to develop the world’s first wireless charging concrete pavement.
Mauricio Esguerra, CEO of Magment, said the following in a press release: “This project is a real step forward towards the future of dynamic wireless charging.” He also noted that this project “will undoubtedly set the standard for affordable, sustainable and efficient transportation electrification.”
So, will it work? And what will this mean for our collective EMF exposure? Those are the big questions – watch this space for further updates.
2021: Michigan to Soon Start Working on Electrified Roads
Until now, wireless charging roads were just a concept backed by a laboratory experiment. But, a recent announcement by Gov. Gretchen Whitmer of the Michigan state points towards this concept becoming a reality very soon.
On September 21, 2021, Governor Whitmer announced that the state would be developing its first-ever wireless charging public road that will allow motorists to recharge their vehicles without making a stop.
“Michigan was home to the first mile of paved road, and now we’re paving the way for the roads of tomorrow with innovative infrastructure, [that] will support the economy and the environment, helping us achieve our goal of carbon neutrality by 2050,” she said.
The plan is to first create an unidentified one-mile wireless charging road somewhere in Wayne, Oakland, or Macomb County. Initially, this construction will not be public because the concept of wireless charging roads is still in its infancy, and there’s a lot to optimize before turning it into a full-blown project.
The Future of Wireless Charging
Imagine a world with no chargers for your electronic gadgets, no plugging in your cell phone, and waiting hours for it to charge. You’d just enter a room, and all your devices would start charging. It wouldn’t even have to be a special room. It could be a room in your home, your office cubicle, or even a restaurant.
Sounds far-fetched, doesn’t it?
The way technology is progressing, this is the foreseeable future. And note that this is not just a concept. The technology capable of doing this already exists.
In September 2021, a group of researchers from the US and Japan came up with a technology that could turn a whole room into a wireless charger.
They say that this room can power smartphones, laptops, fans, lamps, and other electronic gadgets without wires or cables. Your device just has to be in the room, regardless of the location or orientation, and it’ll start charging.
How Does This Work?
Before moving further, let’s first understand how our current charging infrastructure works.
If you’re familiar with the electricity branch of physics, you know that there’s a concept of AC and DC power.
AC stands for alternating currentFundamentals of Alternating Current Alternating current (AC) is a type of electrical current in which the flow of electric charge periodically reverses direction. In contrast to direct current (DC) where... More, which we use for the majority of power transmission and distribution. This is efficient in transferring power without losing much charge. You see AC in operation every day when you switch on anything that doesn’t require a battery, like a light bulb, refrigerator, or even a desktop computer.
On the other hand, DC stands for direct current"Direct Current" (DC) is a type of electrical current where the electric charge flows consistently in one direction. It's like water flowing steadily in a straight line through a hose.... More, which is an energy reserve that can give you power in the absence of alternating current. We use this in cell phones, laptops, car batteries – basically anything that has a battery inside.
So that’s how your cell phone works without plugging in: by reserving the power from alternating current in its battery and using it afterward as direct current.
See, the concept is simple. To power on an electronic gadget, you need a constant flow of current. This can be either through alternating current, i.e., plugging your device on a wall socket, or through direct current, i.e., reserving the power in a battery.
So, if that’s the case, how does a wireless charging room work?
Wireless Charging Rooms
The secret to these rooms lies in electromagnetic fields, or EMF. If you’ve been with us for some time, you know exactly what EMF is. And if you don’t know about it, you can read my post “EMF in Simple Words.”
EMF is basically energy that can move from point A to B without any wires or cables. It’s what your wireless devices use to communicate with the network source.
The prototype that the researchers built for the wireless charging room project is about 100 square feet large, and it consists of aluminum floors, ceilings, and walls. Why aluminum? Because it’s a good conductorThe term "conductor," in the context of electromagnetic radiation, refers to materials or substances that allow for the efficient passage of electromagnetic energy, including both electric currents and electromagnetic fields.... More of electricity, and it doesn’t let EMF escape. Read my post on “EMF Shielding Materials” for more information.
These researchers have hidden a series of capacitors inside the aluminum walls, which create a magnetic field that roams around the room. When you enter that room, your phone’s battery will start receiving that electromagnetic field through a special receiver, and it will begin charging.
Is it Safe?
This room delivers 50 watts of power – a level that’s technically within the safety guidelines set out by the US Federal Communications Commission and the Institute of Electrical and Electronics Engineers.
But are our current guidelines enough for public safety?
As mentioned above, no real level of manmade EMF exposure is completely “safe”. And it’s a compounding problem: the more sources of EMF we introduce into daily life, the higher our cumulative exposure.
In this room, you’ll be continuously exposed to the maximum legal amount of radiation from a cell phone, which is 1.6 W/kg.
And to reiterate, a growing volume of research confirms that EMF’s biological effects begin at exposure levels far lower than what’s in the guidelines. So, just because the room’s emissions are within safety guidelines hardly means it’s safe. See my “Current EMF Standards” post for more information on the complexities around safety standards.
Final Thoughts
To sum up, wireless power comes in a few different varieties. The most basic type uses magnetic induction between a transmitter and a receiver, but for this to work, the two need to be in very close contact. Resonant charging is another variation of this that uses a higher frequency and offers more distance between the charging station and the device.
Beyond that, we have wireless charging that uses radio waves – much like a WiFi router does, only this time transmitting power rather than data. As companies compete to get their tech into your life and your living room, we can expect more developments in this direction. What this will mean is an extra layer of EMF radiation blanketing our homes, offices, and public spaces as we seek to keep all our devices constantly powered up without cables.
All of this accumulating EMF radiation is not safe. Here’s why. So if you can spare a (literal) second to plug in a cable, it will make a difference to your exposure levels and to your overall health. Which is why SYB Healthy Living Tip #44 is Use Wired, Not Wireless, Charging.
It’s an easy way to reduce your cumulative exposure to EMF radiation. Small measures like these are why I always say that the best EMF protection is free.
