# A Look at How Much Electromagnetic Radiation the Devices We Use Emit

Wireless devices have become a part of our daily life and work. As someone who uses them professionally, I decided to measure their electromagnetic radiation to see if they are a threat to my health. The results may be interesting to you.

No, this is not an article for the fifth generation mobile communication standard. In this text, you will learn about the amount of radiation emitted from devices such as wireless routers, smartphones, dumb phones, Bluetooth keyboards and mice, laptops, radio triggers for strobes, tablets, and other equipment.

The term "radiation" has gained quite a lot of negative fame because of nuclear power plants. Taken out of context, radiation doesn't mean anything negative unless you know what is emitted. A fire stove radiates heat. In this article, I will call it EMF radiation, which stands for electromagnetic field radiation.

## What Is an EMF?

When electric current travels through wires, it generates a magnetic field around them. The antenna is two pieces of wire with running alternating current. Imagine you have a battery and two wires. Connecting each to one of the battery terminals creates a current in one direction and when you switch the plus and minus terminals you reverse the current flow. That's basically how alternating current works: it switches positive and negative current. On each polarity change, a electromagnetic wave is created just like when you make a wave in a pool of water. The more frequent the changes are, the more waves are generated. The number of polarity switches per second determines the frequency of the waves in units called Hertz (Hz). If you do a manual switch, the frequency will be one or two switches per second or 1-2 Hz. The power cables in your home are running alternating current that is 60 Hz, which means there is a device (generator) that generates current of different polarity 60 times per second.

## Why Is the Frequency of Wireless Devices So High?

Can't we use the 60 Hz power cables to transmit data? Why do we use devices of such a high frequency as the 2.4 GHz router? The answer is: yes, we can use 60 Hz for data transfer, but it will be very slow.

Let's forget about electronics for a while and pretend we have two people on two mountain peaks that send smoke signals to each other. They have agreed to send a number of smoke signals during each hour of the day. The number of smoke signals determines a letter of the alphabet. For example, from 1 pm until 2 pm, one of them sends three smoke signals. This is the letter "C," being the third letter in the alphabet. During the light part of the day, they can send messages only with dozen letters. They have to wait for the next hour or the next day in order to send the next letter.

That's how wireless communication works (a very simplified description of frequency modulation or FM). Each wave that is sent contains a small package of information. If we pretend we are sending one letter per electromagnetic wave, this means we can transfer 60 letters per second. Sending the text of this article over a 60 Hz network would last about six minutes, which is very slow for today's standards. This is why they have decided to raise the number of waves per second in order to send more data in less time, and that's how we ended up with gigahertz communication.

## How Is Electromagnetic Radiation Measured?

Electromagnetic radiation is different from nuclear plants' radiation. With a dosimeter, you can measure the radiation of foods, building materials, rocks, etc. The electromagnetic radiation is not measured with those devices, but with specialized EMF meters. They work like radio receivers, which analyze the received electromagnetic waves and display the result from the analysis on the screen. There are cheap meters that have only one antenna (one-axis meters), and in order to show correct results you have to point them in the right direction. They can cost less than \$50, but can give quite false results. There are more expensive tools that have three-axis antennas that analyze the signals in 3D space, so you don't have to point them to a specific direction. That's the kind of tool I purchased for these tests: Extech 480836.

The tool works in the frequency range of 50 MHz (50,000,000 Hz) to 3.5 GHz, which is ideal for the devices we, as photographers and filmmakers, use. The more expensive meters have an option to customize the frequency range, and they may allow you to measure greater frequencies (like those for 5G antennas). The tool had good reviews and was used by local radar engineers, so I decided to buy it.

It can measure in different units, but for this article I will stick to microwatts per square centimeter, abbreviated as uW/cm^2 (mW is reserved for milliwatt, while uW is microwatt). The Watt is a unit for power of different kinds. It can be heat power. It can be mechanical power, as well as electromagnetic power.

There is heat production from the electromagnetic waves as well, but not in the conventional way we are used to. A few decades ago, soldiers found that staying in front of a military radar made their bodies warmer. This is how the microwave oven was invented. It was found that electromagnetic frequency of 2.4 GHz heats water, while other common materials are not affected. That's why if you put a plastic cup in a microwave oven, it won't heat, but if you put water, it reacts and gets hot. That same frequency is used in many wireless (and Bluetooth) devices, and the difference is only in the input power that is used.

## Tests

During the tests, I used both devices I work with and devices I borrowed from friends. The measurements have been provided at spots where the meter gives a zero reading without the device. This helps ensure that the values on the display will be those that are introduced by the tested equipment. The photos have been made with a DSLR without any wireless activity.

The EMF meter is designed to measure high frequencies, which means the magnetic fields' radiation from the power cables are filtered away. The meter is factory calibrated to show an alarm above 0.4 uW/cm^2. We will talk more about the effect from different values and the established standards further on in the article. For now, keep in mind that most of these devices are set to warn you when they reach levels above 0.4 uW/cm^2.

### Laptop

Fewer and fewer people today use desktop machines. Those that do are aware of the power per dollar advantage, but many others swap the power for mobility by using a laptop, especially with the function for Wi-Fi connectivity. Wi-Fi and Bluetooth are almost identical technologies (from a radio frequency standpoint), because they work in the 2.4 GHz range, but they differ in their power consumption and protocol of communication. Bluetooth is used for close-range devices (wireless mice, keyboards, graphic tablets, smart watches, communication of your phone with your car). Wi-Fi is used for connection with devices that are farther away. For that reason, Wi-Fi consumes more power and drains your battery faster.

The meter shows a value between 4 and 6 uW/cm^2 with occasional peaks up to 13-15 uW/cm^2 on the device. The more internet-heavy the operation is, the more radiation is emitted.

The radiation gets weaker the same way as light: by the inverse square law. This means that by doubling the distance from the source, the radiation gets four times weaker. A laptop with Wi-Fi and active internet use has about 1.5 - 2.2 uW/cm^2 radiation about four inches from it. About a hand distance (two feet), where your head is, the radiation is between 0.4 and 1.0 uW/cm^2.

I have tested laptops with metal casing (2010 MacBook Pro, 2017 MacBook Pro) and one that is all plastic (an old Toshiba Satellite). The radiation at the top was identical. The radiation below the laptop was different: those with metal plates at the bottom blocked some of the signal. It was about 0.4 - 0.7 uW/cm^2 when the internet connection was actively used.

Even if the laptop is not used, but turned on, there are applications that are connecting to the internet for various reasons: checking email, checking for new messages, checking for software updates, etc. This means it will generate radiation.

### Wireless Mouse, Wireless Keyboard, Wireless Graphic Tablet

Those are the computer devices that usually utilize the Bluetooth as a connectivity protocol. When not used, they do not radiate anything. When using a standard three-button wireless mouse, the meter showed between 1.0 and 1.8 uW/cm^2 radiation. A wired mouse had no radiation. The further the device is from the computer, the more radiation it emits. I have measured values up to 9 uW/cm^2.

Wireless keyboard away from the computer

This is true for all wireless devices that detect they have a poor connectivity (including phones with poor connection): they increase their emitting power in order to find equipment to connect to.

The same tests were performed with a wireless keyboard. When Bluetooth on the computer was turned off, the keyboard showed higher radiation values, as it was trying to find a device to connect to. After connecting, it emitted radiation only when keys were pressed. A value of 0.9 uW/cm^2 was measured.

The same test were performed with a wireless Wacom Intuos Pro tablet, and it showed similar results when in use. Using those devices with a cable (even with a wireless adapter on the graphic tablet) showed no radiation at all.

### Wireless Router

The most common routers today are the 2.4 GHz ones. There are routers on higher frequencies as well, such as 5 GHz, as well as combined with several frequencies. I tested a 2.4 GHz and a combined version. As a side note: 5 GHz router is not a 5G thing. 5G is "a fifth generation" communication standard, where the antennas work on frequencies between 30 and 300 GHz. That's not the case with the wireless routers.

Although nobody puts the router on their head, I found that the radiation right on the device was 50 uW/cm^2. Three feet away from it was about 0.54 uW/cm^2, and seven feet away it was about 0.19 uW/cm^2. The 5 GHz router had a radiation value of 1.8 uW/cm^2 about seven feet away from the device.

#### Turning Off the Wi-Fi of a Router

The router is a piece of equipment that allows distribution of one connection stream (cable) between multiple devices. The connectivity can be achieved via wireless signal or with a cable. If you prefer to use an internet connection with a cable, do not forget to turn off the Wi-Fi of the computer as well as the Wi-Fi of the router. Most of you know how to turn off the wireless connectivity of the computer, but it's a bit harder on the router. Older routers had a button for switching Wi-Fi on and off. Most modern routers allow changing of that setting when you open their network address from your browser. They will show you a "web page" where you can find the wireless settings and turn the wireless connectivity off. In order to do that, first make sure that your computer has an internet connection with a cable and with Wi-Fi turned off. Then, you can follow the steps to turn off the Wi-Fi from the router. In order to do that, you have to find its network address.

On Windows, press the Windows keyboard key + R, and you will see a small window with a field to type a command into. Type "cmd" and press "Enter." In the terminal window that will open, type "ipconfig" and press "Enter." Find the line that reads "Default Gateway" and you will see a network address like "192.168.1.1" or something similar.

On Linux, open the "terminal" application where you must type "route -n" and then press "Enter." The network address of the router is under the "Gateway" column.

On Mac OS X, press the loupe at the top-right corner and type "terminal." Press "Enter," and in the terminal window, type "route -n get default" and press "Enter." Find the line "gateway." That's the router address.

### Computer Tablet

These devices are usually connected via Wi-Fi or have a SIM card to allow internet connectivity via mobile communication providers. When their screens are off (but Wi-Fi is turned on), they have constant peaks usually in the 4-6 uW/cm^2 range (sometimes quite higher) every few seconds depending on the behavior of the installed applications. The intervals I measured were 5-6 and 30-40 seconds. About two feet away from it (where your face is), the values are between 0.6 and 1.0 uW/cm^2. If children use the tablet, they will be closer to the device, and the radiation power will be greater.

When under heavy internet use, the tablet emits between 6 and 17 uW/cm^2 on the device and about 2 uW/cm^2 two feet away from it.

### Phone

I tested an Android phone, an Apple iPhone, and two models of the so-called "dumb phones." The smartphones were tested with Wi-Fi on and off, when talking, and when browsing the internet. The old phones were tested with phone calls only. One should note that 4G signals use frequency bands partially out of range of my measuring device.

The common thing with all smartphones is that the most radiation comes from the Wi-Fi and the mobile used data. If you are making a long phone call and you have Wi-Fi or mobile data on, the peaks from the internet activity will cause higher radiation values.

The measured values of Wi-Fi-enabled phones were with peaks between 4-6 uW/cm^2 when the phone was actively used for internet connectivity, e.g. watching videos. The radiation was measured on the phone itself. About two feet away the radiation, drops to about 0.6 uW/cm^2 with occasional peaks.

Browsing through the mobile data channel gave a little lower measurements, between 0.4 and 4 uW/cm^2 on average, but there were higher peaks as well.

The greatest difference in the measurements was during the phone calls. The Android phone had the lowest radiation, with maximum values between 0.6 and 1.0 uW/cm^2. The iPhone was next, with radiation values above 2 uW/cm^2.

The highest and shocking values were from the old dumb phones, constantly going between 100 and 700 uW/cm^2.

### Hands-Free Accessories

If you are concerned with the mobile phone radiation you have probably thought about hands-free options, such as wireless headphones.

The job of these devices is to be connected to your phone. They have the same performance regardless of your phone's wireless connectivity options. They are like small routers that emit radio frequencies to communicate with your phone. They usually work on 2.4 GHz and emit between 4 and 7.0 uW/cm^2 almost constantly, even if you are listening to a music file on your phone. The reason for the radiation is the wireless communication with your phone.

I haven't measured the connectivity of the phone with a car that supports Bluetooth connectivity, nor have I tested a smart watch, but I guess it would be the same as a phone or a tablet.

Back to accessories that are exclusively used for photography. The strobes (or flash guns) we use are usually triggered remotely using radio communication in the 2.4 GHz range. I tested my Elinchrom Quadra, which has a receiver built into the battery pack and a sender that is mounted on the camera's hot shoe.

Turning the battery pack on had a peak of about 1.5 uW/cm^2 for less than five seconds, and then, the meter showed zero. The sender (or the trigger) device on the camera showed about 0.06 uW/cm^2 when firing the flash and about 0.2 uW/cm^2 when changing the power settings. With the information above, I can say that this piece of gear has almost no radiation.

### Wireless Microphones

Lavalier microphones are very handy when you want to work quickly, capturing a subject from longer distances and without any wires. I tested a Sennheiser lav mic kit that works between 600 and 700 MHz (0.6 to 0.7 GHz).

It's a very popular piece of gear. I use it mostly for backup sound recording. The receiver has very low radiation, while the sender showed values between 10 and 30 uW/cm^2. The radiation from the microphone (connected to the sender) was about 5 uW/cm^2. The reason for that radiation is probably the volume of information the device is trying to send, because they want to give you a signal with the greatest quality.

## So? Is That Dangerous?

### The WHO

There are two schools of thought that try to answer this question. The first one is the official position of governments and official health organizations, such as the World Health Organization (WHO). The latter published an article in 2006 saying that they have invested a great amount of resources into EMF side effects, and they didn't find any relation between diseases, especially cancer, and radio frequency radiation, though they note public perception often differs significantly.

## Independent Scientists

Some independent scientists who researched the matter in the last 30 years have claimed that even values between 0.05 and 0.1 uW/cm^2 can affect the heart, the nervous system, and are a possible cause of cancer.

On the other hand, a systematic review of such studies that have claimed effects have found issues with the way experiments were conducted and that it was likely there are no such physical effects.

### The Government

There are no established international standards. The "safe exposure limits" are established per country, and they vary quite a lot. For example the maximum limit in Italy and Russia is 10 uW/cm^2, while in the USA the limit is set to 1,000 uW/cm^2.

### The Mobile Phone Manufacturers

If you have an iPhone, there is a section in the license agreement called "RF Exposure." There it basically says that it's not a good idea to carry the phone close to your body. I am sure there is a reason for that warning even if the measured values were far less than the USA-established limit of 1,000 uW/cm^2.

### The Measuring Devices

I have used three measuring devices, and all of them had a limit of 0.4 uW/cm^2, after which the device showed a warning indication.

## Shielding From EMF

There can be many other sources of EMF, like smart meters, smart refrigerators, baby monitors, neighbors' routers, etc. I found that standard aluminum window blinds (even opened) shield from the outside exposure and lower it about 3 times. Any metallic mesh (with small holes) does the same. A second layer of any of these improves the shielding. There are commercial products, such as blankets, hats, and clothing.

## Conclusion

From all the measurements, I found that Wi-Fi enabled devices had one of the greatest radiation: between 4 and 17 uW/cm^2 when actively used or when apps on the device made regular checks. This means that even if the device is not in use, but close to your body, it may be exposing you. If you decide to take precautions against excessive EMF, make sure your Wi-Fi and mobile data are turned off when making phone calls.

If you decide to use a wired connection, this may be a benefit for your health in the long run. If there is no proven harm, you would have had some inconvenience by using cables, but at the end, you can do your job this way as well.

We are interested to hear your opinion on the matter. Have you performed tests with a more expensive device? Did you have negative health effects with excessive use of wireless devices? Did you have any improvements after you refrained from using wireless technology one way or another?

Disclaimer: the measurements and conclusions above are anecdotal and not intended as substitution for scientific research.

Oh god, lets hope the non sciences nutters don't see this. Its good your showing the uW/cm^2 energy because you only have to see how long a microwave takes to warm water to see how much energy is required. It takes 4,200 Joules per kilogram per degree Celsius, so at the highest level recorded above at 17uW/cm^2 or 0.000017 W/cm^2 it would take 68 hours to heat 1 gram of water (1 cubic centimetre) by 1 Celsius.... even at the US's highest amount it would take an hour... Not forgetting the invers square law will apply to the power dissipation... The simply fact is there isn't enough energy in any device you will have to do anything and any base tower you wont be able to get close enough to warm you up either...

If you're going to hate on people who aren't on the up and up with science, can I call you out on your grammar?

A 5 W lamp doesn't produce that much heat while a 5 W laser can burn through your skin. It's not the wattage that is the primary source of action, because wattage can be applied for mechanical power as well. It's the frequency that does the action. The measurement of uW/cm2 is not just heat production. It is also a measurement of area, not volume. Applying that to 1 gram of water is not correct. It is applied on a layer of material. Can you say how many layers of material are in 1 gram of water? How many layers of tissue are there in your body and how many square centimeters there are? Also, why would so many researches tell that even low values can cause harm in the long run (an article from 2007 on their website)?

RF is not just about producing heat, because you don't take into an account how those vibrations affect the cell membrane, for example or the red blood cells. If you do a little research you will find that the red blood cells start clustering when they are exposed to radiation from a phone.

Why would Apple warn you that you should not hold the phone close to 5 mm to your skin? This means, you should not touch the device unless you are wearing thick gloves. The WHO also says there is a potential carcinogenic effect in the long run. Why would they say that if the heat production is so negligible?

Erm… energy in = energy out, you cannot destroy or create energy, just convert it from one form to another ... so a 5w laser will still in total have the same amount of energy usage as a 5w bulb, just more in photons than heat, in a more focused way. That's the 5w bit..
I used 1ml of water as an example as its 1cm x 1cm x 1cm with the same exposure surface as the uW/cm2 units
This is based on the assumption that all the energy is dissipated in the 1cm depth, which is unlikely, its likely to be dissipated over a very long distance making the effect even more irrelevant.
If you were to compare this energy with the Sun, which can easily be 150000 uW/cm^2 of EMF just in the visible spectrum, 17uW/cm^2 is a bit lardy dar..

"vibrations affect" in atoms is heat btw and it takes energy.

Apple simply are putting it in their terms so any nutter litigation is not there problem because the nutter didn't follow their instructions.. simple way to avoid being sued...

also if your going to "quote" and article from 2007 on a website, put a link to it..

The article starts good with a structured and neutral look (although a bit short) what RF actually is. The measurements are good, although the explanation or judgement of the results is a bit weak (e.g. why the 'dumb phone' emits so much more power).
If the scientific community has not come to any conclusion and there are no studies with reliable indications of any side effects by RF radiation, why does this article makes such recommendations in the conclusion, stating possible 'health benefits'?? That's illogical, if not borderline fear-mongering.

Why Apple would tell you that the device shouldn't be closer than 5 mm to your body, which means you have to never touch the device? Is that fear-mongering?

The WHO wrote an article in 2007 that there is evidence that the EM radiation are carcinogenic, but according to them the evidence was not of such a large volume to move the EM radiation to a category where it surely causes cancer, but into a category of a probable cancer cause.

Firstly ELF is between 0~30Hz so lower than your house AC supply, so if you are worried about that, you might want to cut your house off... also you might want to read this... https://academic.oup.com/jnci/article/103/16/1211/904716

That's why I said "EM radiation" which stands for "electromagnetic radiation", and I didn't say RF radiation (which is EM radiation from 20 kHz to about 300 GHz). The low-frequency EM radiation has a greater power. The RF radiation usually has a greater frequency.

Your Quoting a image with ELF... you can't quote one thing and then talk about something else... more smoke and mirrors... also the electromagnetic spectrum is much broader from around 3hz (ELF) to 300 EHz (Gamma rays) (EHz 10x18)

Apple is driven by potential law suits of stupid people, nothing to do with real EMF or RF radiation. And your WHO article also states 'potential' not 'proven'. I hope you understand the difference. And yes, that is fear-mongering if rumors, assumptions and fear of legal actions are the drivers, not scientific evidence.

BTW, it's not "my WHO article", but theirs, on their website. One year before that (2006) they say they don't find any problems at all. None. Period. One year later they say there could be problems (despite the public research papers and the lawsuits from Noble prize winners like in the link below). To say that this means there is evidence, otherwise would be quite irresponsible to tell people "there is a possible cause, because someone on the bus stop told me." They just say that there is evidence that it causes harm (like cancer), but they think these are isolated cases.

Again you forget the legal framework of US. In a country that goes nuts over suing each other over minute things it is suicidal to make clear scientific statement that there is no conclusive evidence about harmful effects of EMF or RF radiation. Coming back to your article: it would have been honest and clear to state what you don't know. Instead, with nothing in your hands but suspicions, you run the fool proof way of 'better be safe than sorry' and make 'recommendations' about 'may be benefits. That exactly is my point of critics. Over end out.

Many responsible scientists have been trying to get the regulatory agencies to incorporate the recent toxicology studies, but for some reason the regulatory agencies are not keen to upset the apple cart (or is that the 'gravy train'?) with some piddling concern about human health.

As somebody who studied electrical engineering for 5 years, this article upset me. It demonstrates how a little knowledge can lead to misunderstandings and an overabundance of confidence.

I once bought a power center that showed how much electricity was being used when things were plugged in and turned on. So naturally I got bored one day and probably plugged every single thing I owned into it just to see what they drew.

Kind of feel like that's a similar to how this article came into the world. New toy? Gotta use it.

I run a commercial lab and do FCC, CE, IC, UL, and Military EMI/EMC testing every single day. I sent this around the lab and everyone is just shaking there heads at this article.

I'll admit that I didn't find the article interesting enough to read the whole thing. My son, who is a hardware engineer for Microsoft, just shook his head when he read it, and said Pfft! Everything they design is tested for EMF radiation. If there is too much radiation, it's back to the drawing board.

The problem is with the "too much" number. It's usually hundreds or thoudsands times above safe limits found by independent medical research (in the last 30-40 years).

Are you sure, or is that your opinion.

There were links here posted pointing to government sites showing studies that even date back to '71. One of the studies is this:
https://ecfsapi.fcc.gov/file/10429016089243/WIF%20threat%20Martin%20Pall...

You can find many more that have been made by respectful scientists, including Noble-prized ones. All they show the harm done by high and low-frequency EMF with density lower than the most conservatively-established standards in any country today (e.g. 10 uW/cm2 in Italy, 1,000 uW/cm2 in USA).

As other readers have said already, it's a bit irresponsible to publish an article on a subject like this (which tends to attract people with irrational fears) without running it through a serious review by people with scientific and engineering knowledge.

There is no plausible physical mechanism by which such low-power emissions at such low frequencies (and yes, microwave emissions are still "low frequency") can harm a human body. They cannot induce enough heat; the wavelength is too long to have a probable chance of interacting at the cellular level; and they cannot impart enough energy to disrupt cell membranes etc even if they did.

You're more likely to be harmed by the heat emitted by your phone's battery and CPU than by its microwave emission.

As for that Apple EULA? Well, there's only one group of people more risk-averse than scientists and that's lawyers. The statement isn't there to protect Apple from the reality of injuries caused by phone radiation; it's there to protect Apple from people who *think* they've been injured by phone radiation.

Low power emissions of rf frequencies can affect cell signaling. It is a non-thermal affect that has been shown in many studies. See this lecture by one of the researchers: https://www.youtube.com/watch?v=kv_p30L8GZ0

Sudo science... a bloke on youtube… how about a collection of links to pier reviewed papers published by a broad spectrum of scientific journals showing clear evidence of what you are claiming... however there is bugger all evidence... other than morons being milked for cash for problems they don't have...

"The researcher, Rony Seger, was recently sanctioned by his institution (The Weizmann Institute in Israel) following a finding of “serious misconduct” involving data manipulation. Specifically, the institute barred him from supervising graduate students, even future ones..."

It appears he had papers retracted, and can no longer teach, because he was caught manipulating data.

So how about a credible source proving this isn't pseudoscience peddled by conspiracy theorists?

Inb4 this is what is causing Covid.

Fstoppers gotta be desperate to post this kind of crockshittery to generate traffic...

I never thought I'd say this but.... please go back to bag reviews.

"If you decide to use a wired connection, this may be a benefit for your health in the long run." unless you trip over the cable and break your neck.

"A little information can be more dangerous than none at all" This statement applies to this article more than any other I've read on fstoppers. Seriously next time don't just research via internet, try actually picking up a textbook or asking an engineer/scientist to review your article before posting it!!