Radio Sunday #9 Radio Safety

In a reaction to my post looking at 5G, there was a great deal of talk about the limits and whether or not they're realistic.  This ranged from the view that, “we don't know everything and I wouldn't be surprised if there are long term effects we don't know of” to the idea that saying heating is the only proven health impact is just bullshit.   

I thought it would be worthwhile to go over some data.

To begin with, the view I stated that the only recognized cause of injury from radio fields is heating isn't my conclusion, it's the conclusion of every national organization around the world that studies these effects.  If you think the regulatory agencies wouldn't be dying to inject themselves into your life and jump at the chance to regulate something else, I think you have an overly optimistic view of big government agencies. 

Let me start by presenting a summary page from a Canadian RF Safety document, which is managed by Health Canada under Safety Code 6.  Health Canada says they determine a radio frequency level at which effects are seen and then reduce the exposure limit by a factor of 50 for safety margin. 

It's important to recognize that they don't start these studies saying, “let's measure the heating effect”.  Studies are started out under many different protocols to measure anything they can find. The document this is from is called RF Toolkit–BCCDC/NCCEH from Health Canada, dated 2015.

Summary
• Studies using animals have historically proven useful for investigating health effects; a large number of such studies have recently been conducted (2005–2012) to evaluate whether exposure to radio frequency (RF) fields has adverse biological effects.
• Long-term bioassays, designed to determine whether RF exposure either alone or in conjunction with known mutagens can initiate or promote development of cancer in animals, have been uniformly negative.
• Studies of RF fields and toxicological effects such as DNA damage, micronucleus formation, apoptosis, reactive oxygen species, and gene expression changes have been inconsistent and the results contradictory. Positive studies have proven difficult to replicate. This lack of consistency reduces the likelihood that exposure to RF fields has toxicological effects in animals.
• There is no consistent evidence that exposure to RF fields produces biological effects in animal central nervous systems. Most recent investigations have been unable to confirm Swedish studies suggesting that RF exposure alters blood-brain barrier permeability; however, other aspects of brain physiology are less well studied. Behavioural investigations of the role of RF exposure on animal learning and cognitive function are mixed, with most being negative.
• Immune function studies have been mostly negative, although most of the studies to date have been conducted in adult animals. Earlier Soviet study results, indicating that serum taken from RF-exposed animals could increase embryo mortality when injected intraperitoneally into pregnant rats, have not been confirmed. Notwithstanding this, more studies are needed on RF effects in young animals.
• Effects of RF exposure on endocrine function, particularly on melatonin levels, have been negative, and studies of their effect on reproductive function in female animals have also been negative.
• Overall, studies have not shown convincing evidence that RF field exposure produces adverse biologic effects in animals. There are many negative results, and the relatively few positive results are rarely replicated in confirmatory studies. Most of the recent studies are characterized by good research protocols including appropriate control of thermal effects and excellent animal care along with appropriate use of reverberation chambers to ensure uniform specific absorption rates (SAR) in whole body RF dosimetry, or of animal restraints in the case of RF fields applied to specific organs such as the brain. These recent studies have generally shown no association of specific outcomes with exposure to RF.
• There is no recognized biologic mechanism by which RF exposure might operate to cause adverse biological effects in animals.  [Bold added: SiG]

As I said in one of my responses, about the most stupid thing anyone could say is, "I'm sure we know everything".  The other side of that observation is we really do know some things.  It's possible entirely new fields of science will be discovered in the next hundred years, but it's not a high probability.  It's possible that some mechanism of damage from radio will be discovered in the next hundred years; I also view that as low probability.  Independent of that, the experimenters running these radio exposure experiments have learned much the last 50 years and gotten better at getting more consistent results.  It's possible they'll find effects that are smaller than what they can measure today.  As an RF designer, I can tell you getting radio energy into some place you want it, and getting it to do what you want it to do, isn't always trivial.  Just exposing the animals to a radio source doesn't mean they're going to get the dosage the researchers want.  The researchers need to be good at what they do.

The results of studies trying to find damage from radio exposure have generally not been statistically significant.  As the summary conveys, studies do sometimes show up that give a result that's concerning.   When those studies are redone by more experimenters, the results tend to not show up.  When effects come and go like that there are two reasonable conclusions: the first is that the result was random or due to something other than the RF energy and that other thing wasn't controlled properly between groups.  The other reasonable conclusion is that it's a weak effect. 

Most people act as if radio is a new thing in human experience.  It is not.  As a species, we've been bathed in radio waves for all of human history from natural sources, just not manmade sources.  Earth's atmospheric processes produce radio waves.  The sun produces radio waves.  Other planets produce radio waves.  We measure solar activity by the radio energy it puts out at 2800 MHz (the 10.7 cm solar flux).  That's a microwave frequency, higher frequency than many cellphone systems, that humans have been exposed to for as long as we've been on the planet. 

Radio is electromagnetic energy just like light, and the analogies to light hold over wide ranges of frequencies.  Modern physics teaches that energy is inversely proportional to wavelength; the shorter the wavelength the higher the energy.  The wavelengths of radio waves run from thousands of meters down to a millimeter.   That's a wide range of energy values, but the highest energy radio is still non-ionizing radiation, much weaker than UV or Gamma Rays.  Like light, if radio is intense enough to cause burns, it's harmful, but if no harm is detected, it's not doing anything that will show up in 10 or 20 years.

This should be good news!

A so-called Microwave Diathermy - heat therapy - machine (300 MHz is not microwaves, it's the low end of UHF radio, although 30,000 MHz - 30 GHz is microwave).  If you have gotten physical therapy with diathermy, you've used RF heating.  Source