Forget 5G, people were once afraid of radiation from monitors

Radiation is everywhere. There is no escaping it, and there is always some background radiation, which is what we struggle with the most. This is of course scary, because ionizing radiation can make us sick in various ways. So it doesn’t help that some of the technologies we have in our homes also produce radiation with potentially harmful effects.

Nowadays people are worried about their smartphones and high frequency radio waves like those used in 5G networks and even Wi-Fi, but before cell phones were even a thing for the average person, it was CRT monitors and TVs, people were afraid of them would develop their own green glow.

A quick summary of how CRT displays work

If it’s been too long or you’re just too young, you may not know how those old CRT TVs and monitors worked. To understand why people thought they were catching harmful rays, you need to know the basics of how they work, but we’ll keep it short!

Essentially, high-voltage electricity is used to fire a beam of electrons through a vacuum. The beam excites phosphors on the back of a glass pane, which then emit light. The beam is passed across the screen to draw an image line by line. It moves so quickly that it can, for example, draw thirty or sixty complete images in a single second. This is completely different to how modern flat screens work! This is why light gun games only work on CRTs.

People were afraid that CRT screens would make them sick

Now the idea that CRTs (cathode ray tubes) could emit harmful radiation is not unfounded. When these high-energy particles hit the phosphors in the screen, more than just light is emitted. Remember that what we call “light” is actually just the visible part of the electromagnetic spectrum, and a small percentage of the energy in the beam is converted into X-rays.

X-rays are an example of ionizing radiation. The kind of radiation that can cause problems like cancer! Of course, even X-rays are not really dangerous to health at very low levels of radiation. However, long-term exposure can be a problem. This is why your dentist goes to another room when you have your mouth x-rayed. While you only get an electric shock at your checkup twice a year, your dentist is busy all day, five days a week. That can add up!

There were many crazy “protectors” for sale

There was a time when I couldn’t open a computer magazine without seeing some kind of “radiation filter” for CRT monitors. This wasn’t really a thing for TVs as I suspect people felt the distance to them wasn’t a problem. However, you sit just a few feet away from your CRT monitor and may spend eight hours a day in that spot.

In fact, you can still buy them today from places like eBay.

Not only did these “filters” promise to reduce radiation (with a neat little table), they also acted as anti-glare filters and sometimes promised to reduce eye strain. Just like modern glasses to reduce eye strain. However, it was probably no more useful than radiation protection stickers and Wi-Fi radiation shields.

Why this belief was nonsense

So was this concern about radiation from CRTs true? Was buying these filters actually worth it? I can’t say if they helped with the glare or eyestrain, but they simply weren’t necessary to reduce the harmful radiation from a CRT.

CRT manufacturers were well aware of the X-rays produced by CRT technology, which is why the tube’s glass contains (among other things) lead. This means that nothing harmful can leave the CRTs inside.

This quote comes from one of Dr. The study carried out by WM Zuk and colleagues sums it up well.

Due to the relatively low operating voltages of VDTs, the X-rays produced in the cathode ray tube are low energy and not very penetrating. These X-rays are absorbed by the glass of the CRT and do not penetrate outside. In fact, the thickness of glass used in the cathode ray tube has much higher X-ray shielding properties than are required for the voltages at which VDTs operate and is capable of absorbing X-rays at an energy significantly higher than that found in the Cathode ray tube is generated. The results of X-ray measurements confirm this statement.

Although CRTs do produce X-rays, they are so low-energy that they cannot penetrate the glass of the screen. Using instruments that measure harmful radiation, it is clear that no harmful radiation is emitted from these devices.

There are still people today who use CRTs in retro computer configurations or for retro gaming on consoles. CRTs still have many advantages over modern flat screens, but if you’re somehow worried that using one might be harmful to you, there’s no need to worry. However, you should wear sunscreen when you go outside because the sun really is a deadly laser.