THE NEBULOUS POSITIVE EFFECTS OF NEGATIVE IONS
They reduce particulate matter in the air, but offer little else of benefit to your health
I've always enjoyed visiting Niagara Falls. Watching that mass of water hurl over the edge and crash onto the rocks below is an awesome sight. But it may be more than that. Breathing the air around the falls may have a positive effect on health. That's because of its content of negative ions, or air vitamins, as they are called by some overly enthusiastic supporters of their potential health benefits.
Our story starts with a discovery made by the 1905 Nobel Laureate in physics, Philipp Lenard. The man was undoubtedly a genius — and a despicable human being. Educated in Hungary, then in Germany under famed chemistry professor Robert Bunsen, Lenard became an early member of the Nazi party and a huge supporter of Hitler who made him head of Aryan science. Lenard was a fervent anti-semite, who in a speech once proclaimed that “the Jews must be sunk right down to the centre of the Earth.”
“Germany should rely on German physics” he maintained, “not on the Jewish fraud” as perpetrated by Einstein, whom he viciously attacked for having introduced a “Jewish spirit” into physics. Lenard also resented Wilhelm Röntgen's being awarded the 1901 Nobel Prize in physics for the discovery of X-rays, a discovery Lenard claimed to have made.
While Lenard's politics and character were contemptible, his science is deserving of accolades. Of interest here is his 1892 paper in which he described how the splashing of falling water charges the surrounding air with electricity, known today as the Lenard effect. At the heart of this effect are electrons, the glue that binds atoms together in a molecule. These bonds can be broken by the input of energy, such as water smashing into a surface. On impact, some water molecules are wrenched apart and the negatively charged electrons that had held the atoms together are released, only to be snatched up by oxygen, nitrogen and carbon dioxide, components of the surrounding air. These now become negatively charged and constitute the negative ions that can be detected around waterfalls.
Prompted by Lenard's discovery, a number of scientists became interested in the effects of breathing such electrified air. Though these studies were generally not of high quality, they seemed to agree that negative ions can produce a positive effect. In the 1950s, Prof. Albert Krueger, a University of California bacteriologist, was the first scientist to take a serious interest in the effects of negative ions on living tissues. He chose to study the trachea or windpipe of animals, since it is the primary zone of contact with inhaled air ions. By the time Krueger began his experiments, it was known that air could also be ionized by radioactive substances. He used beta radiation, essentially a barrage of electrons, emanating from radioactive tritium to generate negative ions that were then directed at trachea tissue. Krueger was able to document a variety of biochemical changes, including alterations in the production of neurotransmitters such as serotonin.
The demonstration that inhalation of negative ions can have an effect on biology unleashed a cavalcade of research. Plants, it was found, also release negative ions as they photosynthesize. This was quickly linked with the supposed benefits of “forest bathing.” A number of studies, albeit not ones I would call compelling, have indeed suggested that spending time in green spaces results in enhanced relaxation, reduced tensions and an improved mood. This was now rationalized on the basis of trees producing negative ions.
If those trees surrounded a waterfall, the beneficial effects might even be greater. So, Chinese researchers enlisted volunteers, including some suffering from chronic fatigue syndrome, to spend a week in the vicinity of the Huangguoshu waterfall, the largest in Asia. The subjects filled out questionnaires on the basis of which the extent of their fatigue, anxiety and depression were evaluated. Their scores improved as the week passed. Furthermore, blood tests showed a decrease in markers of inflammation and an increase in the blood's antioxidant capacity.
None of this is what we would call hard science, but it is enough grist for the mill that grinds out pseudo-science. Like the ability of Himalayan salt lamps to improve health. These lamps, made by placing a light bulb inside a block of Himalayan salt, are claimed to release negative ions. Identifying the salt as Himalayan, even though it is mined in Pakistan, adds a certain new-age mystique. But mystique is all that the lamp provides. No negative ions in sight, as can be shown by placing the salt lamp near the intake port of a mass spectrometer, an instrument that can detect even the presence of fleeting ions.
At least salt lamps pose no danger and can even look attractive. The same cannot be said for jewelry made of tourmaline, a semi-precious stone claimed to release negative ions.
The hype is that wearing these bracelets, pendants or rings will relieve pain, increase circulation and enhance mood. Never mind that negative ions have not been shown to relieve pain or increase circulation, tourmaline is not radioactive, so it cannot generate any negative ions. Yet, when some of these items were tested, they proved to be radioactive, and therefore theoretically capable of generating negative ions. It turns out that such items had been doped with radioactive thorium oxide to an extent that if worn constantly for a year, the wearer would be exposed to a dose of radiation that exceeds the annual recommended limit. Amazingly, some of these items are claimed to offer protection against the nonexistent risk of electromagnetic radiation from cellphones by exposing the duped to the real risks of radioactive thorium. Touted as “a perfect gift for anyone who cares about their health,” they are anything but.
While the positive effect of negative ions on health is somewhat nebulous, their ability to reduce particulate matter in the air is on a sounder footing.
Ion air purifiers use high voltage to induce a corona discharge that generates negative ions that then attach to dust particles, giving them a negative charge. These are then attracted to positively charged plates in the machine, or to walls, TV screens and furniture that tend to have a positive charge. Unfortunately, many of these air purifiers produce unacceptable levels of ozone and those that don't are not very efficient.
As far as testing out the effects of negative ions on mood, Niagara Falls seems to be the place to go. Last summer I had a chance to take a ride on the Maid of the Mist, the boat that approaches the bottom of the falls closer than one would think possible. If there is a place to be bathed in negative ions, this is it. I waited for the mood-enhancing effect to set in. All I got was wet.