Do 5G phone networks pose any kind of danger? That's the key question surrounding the current rollout of 5G technology in the US and UK.
There have been protests against 5G, while some campaigners have succeeded in convincing local authorities to pause rollout. However, the amount of misinformation online on the topic is staggering.
We've purposely used official Government and health body advice in this feature rather than relying on information from 5G vendors and networks who obviously have a commercial interest in 5G deployment.
And we're not giving any credence to any conspiracy theories about 5G causing coronavirus - that's fake news for which there is no evidence whatsoever.
So what's the bottom line?
5G networks use radio waves in much the same way as other technologies and forms of communication. But 5G networks use higher-frequency waves than older mobile networks.
The US Food and Drug Administration (FDA) says there are "no new implications for 5G", saying that "the conclusions reached based on the current body of scientific evidence covers [5G] frequencies".
In the UK, Public Health England (PHE)’s view is that "the overall exposure is expected to remain low relative to guidelines and, as such, there should be no consequences for public health".
UK regulator Ofcom has carried out a full UK study into the technology. It measured 16 5G sites in 10 towns and cities across the UK looking at locations where 5G use "is likely to be highest". These locations included shopping centres and transport hubs.
Ofcom says: "At every site, emissions were a small fraction of the levels included in international guidelines, as set by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). And the maximum measured at any site was 1.5% of those levels."
The ICNIRP is an independent non-profit organisation set up in 1992 to assess the impact of electromagnetic waves on people and the environment.
It has now also carried out its own research into the impact of 5G and says there is no evidence of any effect on health.
ICNIRP revised its guidelines on 11 March 2020 saying they are "more appropriate than the 1998 guidelines for the higher frequencies that will be used for 5G in the future."
ICNIRP Chairman, Dr Eric van Rongen, said: "We know parts of the community are concerned about the safety of 5G and we hope the updated guidelines will help put people at ease,".
"The guidelines have been developed after a thorough review of all relevant scientific literature, scientific workshops and an extensive public consultation process. They provide protection against all scientifically substantiated adverse health effects due to EMF (electromagnetic field) exposure in the 100 kHz to 300 GHz range.” This covers the entirety of present and future 5G wavelengths.
The 5G tech used in both the US and UK presently adheres to all the ICNIRP guidelines and network operators are committed to complying with them.
Possible small increase to exposure to radio waves
It is, however, true that there could be a "small" increase in exposure to radio waves. Public Health England (PHE) says: "It is possible that there may be a small increase in overall exposure to radio waves when 5G is added to an existing network or in a new area.
"However, the overall exposure is expected to remain low relative to guidelines and, as such, there should be no consequences for public health."
What about high-frequency 5G (mmWave)?
More spectrum is being made available for 5G. The highest frequencies being discussed for future 5G are around 10 times higher than those used by current mobile networks, up to a few tens of gigahertz (GHz).
In urban areas, high-frequency (millimetre wave or mmWave) tech will be used to maximise capacity and speed. This has already rolled out to numerous US cities (albeit with very limited coverage) and will also come to the UK and Europe in late 2020 or 2021. It's these higher-frequency signals that cause most concern about 5G health.
However, as PHE points out, these high-frequency signals have been used before and have "been present in the environment for many years". They're still categorised as 'non-ionising' like the signals used to deliver radio, TV and Wi-Fi.
ICNIP's Dr Van Rongen said that the body's new guidelines "provide better and more detailed exposure guidance" for the higher frequency range above 6 GHz, which includes mmWave.
Crucially, he added "The most important thing for people to remember is that 5G technologies will not be able to cause harm when these new guidelines are adhered to.”
It's true that mmWave is higher-frequency than the wavelengths used for broadcast, but they're still lower frequency than visible light. And they certainly don't fall into the 'ionising' category like x-rays or ultraviolet.
These waves don't go very far and are blocked by walls and even the human body. PHE says that, while fewer studies have been carried out at higher frequencies, "the biophysical mechanisms that govern the interaction between radio waves and body tissues are well understood at higher frequencies and are the basis of the ICNIRP guidelines.
"The main change in using higher frequencies is that there is less penetration of radio waves into body tissues and absorption of the radio energy, and any consequent heating, becomes more confined to the body surface."