The Random Thoughts of a Geek heading for Banbury

Does 5G pose health risks?

Recently the BBC wrote an article online with the headline “Does 5G pose health risks?”, the first section was:

The 5G mobile network has been switched on in some UK cities and has led to questions about whether the new technology poses health risks.

So what are the concerns, and is there any evidence to back them up?

As with previous cellular technologies, 5G networks rely on signals carried by radio waves – part of the electromagnetic spectrum – transmitted between an antenna or mast and your phone.

We’re surrounded by electromagnetic radiation all the time – from television and radio signals, as well as from a whole range of technologies, including mobile phones, and from natural sources such as sunlight.

5G uses higher frequency waves than earlier mobile networks, allowing more devices to have access to the internet at the same time and at faster speeds.

These waves travel shorter distances through urban spaces, so 5G networks require more transmitter masts than previous technologies, positioned closer to ground level.

While there is technically nothing wrong with what they have said so far, they have succeeded in making the last sentence more sinister sounding than it needs to be:

These waves travel shorter distances through urban spaces, so 5G networks require more transmitter masts than previous technologies, positioned closer to ground level.

While it is true that higher frequencies propagate less far in free space than lower frequencies, there is a nice equation; The Friis Equation that helps you work it out, luckily RF Cafe made a nice chart that shows it in a human readable form:

Another thing that affects propagation of RF in the atmosphere is the amount of water in the air (these are in addition to the attenuation from the chart above):

While these numbers don’t look very big,it helps to know just how big a decibell in terms of attenuation, the two most used in electronics are dB power (dB = 10 log10(PI / PO)) and dB voltage (dB = 20 log10(VI / VO)), for this we are mostly intrested in attenuation in dB power:

 dB attenuation value Multiply the signal power by Percentage of signal left 0 dB 1 100% 1 dB 0.79 79% 2 dB 0.63 63% 3 dB 0.5 50% 4 dB 0.4 40% 5 dB 0.32 32% 10 dB 0.1 10% 20 dB 0.01 1% 30 dB 0.001 0.1% 40 dB 0.0001 0.01% 50 dB 0.00001 0.001% 100 dB 0.00000000001 (1e-10) 0.000000001% 150 dB 0.0000000000000001 (1e-15) 0.00000000000001% 200 dB 0.000000000000000000001 (1e-20) 0.0000000000000000001%

If higher frequencies suck at propagation, why use them?

It’s more to do with bandwidth than the center frequency, however in general the higher the frequency, the higher the available bandwidth, the faster data can be sent and received from a device, the more channels you can have supporting data transfer concurrently.

What are the concerns?

The electromagnetic radiation used by all mobile phone technologies has led some people to worry about increased health risks, including developing certain types of cancer.

In 2014 the World Health Organization (WHO) said that “no adverse health effects have been established as being caused by mobile phone use”.

However, the WHO together with the International Agency for Research on Cancer (IARC) has classified all radio frequency radiation (of which mobile signals are a part) as “possibly carcinogenic”.

It has been put in this category because “there is evidence that falls short of being conclusive that exposure may cause cancer in humans”.

Eating pickled vegetables and using talcum powder are classed in the same category.

Alcoholic drinks and processed meat are in a higher category because the evidence is stronger.

There is a lot of other things in these lists, Radio Frequencies are listed as being in Class 2B “Possibly carcinogenic to humans“. There are over 1000 ‘Agents’ Classified by the IARC:

Group 1 Group 2A Carcinogenic to humans 120 agents Probably carcinogenic to humans 82 agents Possibly carcinogenic to humans 311 agents Not classifiable as to its carcinogenicity to humans 500 agents

you can read the entire list online at the IRAC site, but as I have written about before while there is SCIENTIFIC documentation that does show risks to humans in the presence of RF, if there were not it would be an IARC class 3.

A toxicology report released in 2018 by the US Department of Health, and pointed to by those expressing safety concerns, found that male rats exposed to high doses of radio frequency radiation developed a type of cancerous tumour in the heart.

For this study, rats’ whole bodies were exposed to radiation from mobile phones for nine hours a day every day for two years, starting before they were born.

No cancer link was found for the female rats or the mice studied. It was also found that rats exposed to the radiation lived longer than those in the control group.

A senior scientist on the study said “exposures used in the studies cannot be compared directly to the exposure that humans experience when using a cell phone”, even for heavy users.

Dr Frank De Vocht, who helps advise the government on mobile phone safety says “although some of the research suggests a statistical possibility of increased cancer risks for heavy users, the evidence to date for a causal relation is not sufficiently convincing to suggest the need for precautionary action”.

The first study

Rats and mice were exposed to RFR in special chambers for up to two years, or most of their natural lives. NTP scientists looked for a range of cancers and noncancer health effects. Exposure to RFR began in the womb for rats and at 5-6 weeks old for mice.

The RFR exposure was intermittent, 10 minutes on and 10 minutes off, totaling about 9 hours each day. The RFR levels ranged from 1.5 to 6 watts per kilogram of body weight in rats, and 2.5 to 10 watts per kilogram in mice.

The chambers were shielded rooms with a transmitting antenna that radiated RFR fields, plus rotating stirrers that generated a uniform field. Pilot studies established field strengths that did not raise animal body temperatures excessively.

The rats and mice were exposed to whole body RFR at frequencies of 900 and 1900 megahertz, respectively, from two technologies – Code Division Multiple Access (CDMA) and Global System for Mobile Communications (GSM).

NTP and RFR experts from the National Institute of Standards and Technology (NIST) and the IT’IS Foundation designed and built the chambers specifically for these studies.

What does a whole-body SAR1 of 1.5 W kg of body weight (the lowest exposure level) look like?

Different regions have defined maximum SAR levels for RF energy emitted by mobile devices:

• United States: the FCC requires that phones sold have a SAR level at or below 1.6 watts per kilogram (W/kg) taken over the volume containing a mass of 1 gram of tissue that is absorbing the most signal.
• European Union: CENELEC specify SAR limits within the EU, following IEC standards. For mobile phones, and other such hand-held devices, the SAR limit is 2 W/kg averaged over the 10 g of tissue absorbing the most signal (IEC 62209-1).
• India: switched from the EU limits to the US limits for mobile handsets in 2012. Unlike the US, India will not rely solely on SAR measurements provided by manufacturers; random compliance tests are done by a government-run Telecommunication Engineering Center (TEC) SAR Laboratory on handsets and 10% of towers. All handsets must have a hands free mode.

The three things written above are linked to a small sample area, For the whole-body average the legal limit is 0.4 W/kg has been chosen as the maximum for occupational exposure. An additional safety factor of 5 is introduced for exposure of the public, giving an average whole-body SAR limit of 0.08 W/kg.

The results of the second of the two links above states:

The full results of the National Toxicology Program’s study of cell phones and cancer are finally in. They are somewhat complicated, but ultimately do not support the idea that cell phones can cause cancer.

— Christopher Labos on April 1, 2018

So As we see above the rats were exposed to between 1.5 to 6 watts per kilogram of body weight, and 2.5 to 10 watts per kilogram in mice. If we look at eh whole body SAR limit for the general public of 0.08W/kg we can work out that the rats were exposed to a feild between 12.5 and 18.7 dB higher than the General public SAR limit, and the mice between 14.9 and 20 dB above the limit.

Looking at our table above we can see that works out at the General Public legal maximum exposure being less than 10% of the minimum feild strength of the feild the rats were exposed to and 1% of the maximum the mice were exposed to.

The animals in the study were exposed for about 9 hours a day every day for most of their lifespan.

However, there is a group of scientists and doctors who have written to the EU calling for the rollout of 5G to be halted.

You can see the full list of 253 “scientists and medical doctors” who have signed the The 5G Appeal here. It is intresting the number of people on the list who have no subject knoledge, or have been shown to be pedling snake oil or other woo before.

1. Specific Absorption Rate – for further details try Wikipedia