Anyone who’s been through a health store has heard about ions. If it’s not someone offering samples of ionized water, it’s someone selling ionized bracelets. It sounds wacky, woo-woo, crazy, and as if it belongs firmly in the same realm as crystals, magnet therapy, and cryptozoology (although the kid in me is still holding out hope that both Squatch and Nessie are found), but is there actual science behind this negative ion stuff, or are the people who buy into this stuff totally off their rockers? Today, we venture into what some might consider the realm of the non-scientific to discuss negative ionizers – both the natural kinds (like waterfalls) and the man-made variety (negative ion generators).
Let’s get to it:
I’m almost scared/embarrassed to even ask you about this, but here goes: my friend, who’s into crystals, homeopathy, and other types of alternative health modalities with less than concrete supporting evidence, has been talking my ear off about negative and positive ions. She’s got her entire house decked out with negative ion generators and she’s always trying to “avoid positive ions.” I’ve even seen her ducking past air conditioners. Is there anything to this, or is she crazy?
Maybe. Let’s take a look.
But first, lest we fall into the trap of talking about abstractions (a la “toxins”), let’s define our terms. What are ions?
Ions are atoms or molecules in which the number of electrons is different than the number of protons. In other words, an ion is a negatively (more electrons than protons) or positively (more protons than electrons) charged atom or molecule. Positively charged ions are called cations, while negatively charged ions are called anions. Because they are either positively or negatively charged, ions are “mobile.”
Negative ions generally appear in natural settings in greater numbers than positive ions. For instance, negative ions are generated by moving water – rivers, waterfalls, crashing waves, even showers and fountains – and the presence of negative ions is actually used to identify potential sources of water on other planetary bodies , like Enceladus and Titan. Waterfalls are probably the greatest producers of negative ions, thanks to the violence with which falling water breaks apart on both hard and aqueous surfaces (PDF ). Plants also produce negative ions , especially when exposed to intense light during photosynthesis.
Okay, that’s great and all. Everyone likes waterfalls and all, but does the fact that they generate lots of negative air ions have any bearing on our health?
They can certainly exert “physiological effects” on living things. In fact, that negative and positive air ions could have physiological effects on people was once a field of serious study, but after snake oil salesmen released a slew of air ion generators with the promise that they’d cure cancer, heart disease, and just about every malady under the sun in the 1950s, the reputation of the field was forever tarnished. Research continued, but its name was sullied, and little serious attention was paid to its findings. The result is that anytime anyone even mentions “ions,” they’ll get laughed out of the room or immediately branded a nut job. And that’s a shame, because there is something to this stuff.
Even if some modern skeptics pride themselves on discarding an idea that sounds a little kooky without doing any actual research, that doesn’t mean evidence doesn’t exist. Let’s see what the research says:
Not everyone with seasonal affective disorder (SAD) can afford to slumber amidst the babbling mist of a nearby brook with the gentle caress of the day’s first sun softly nudging them awake. It’s ideal, but studies  indicate that simulating those conditions with negative ion generators, naturalistic dawn simulating lights, and someone blowing raspberries at your face can be just as effective at combating SAD as bright light therapy (okay, maybe not that last one).
Chronic non-seasonal depression has also been shown to be improved with negative ion therapy . High density ion therapy was far more effective than low density ion therapy.
Negative ions (along with bright light and auditory stimuli) reduced subjective measurements of depression , improved mood, and reduced anger in both depressed and non-depressed college students.
In a study  on the salivary responses of people completing a 40-minute word processing task on the computer, exposure to negative air ions reduced the rise in salivary chromogranin A-like immunoreactivity (a marker of stress and anxiety) and improved performance.
The trachea is the windpipe, the passage through which air travels into our lungs. Along the trachea are cilia, tiny organelles which keep airborne particles from passing into the lungs. If cilial activity is inhibited, as in cystic fibrosis, more foreign particles are introduced into the lungs. If cilial activity is uninhibited, the junk is kept out of the lungs and discharged later via saliva and mucus. Research shows that negative ion exposure increases cilial activity in the trachea  of humans and monkeys, while positive ion exposure inhibits it.
Another study  in asthmatic children found that exposure to positively ionized air exacerbated their asthmatic response to exercise.
All told, there does appear to be something to it.
Maybe that’s why sitting around a campfire with your buddies surrounded by towering examples of plant life feels so good. Toss in a nearby river gurgling over stones, throwing mist up in the air? You’ve got a potent recipe for negative air ions. Could that be why camping  out in the great outdoors is so rejuvenating and so energizing ? Sure, you could argue that camping is just a way for us to get away from the madness of work and city life , get some fresh air and exercise, and reconnect with our Primal selves… but there has to be a physiological mechanism for that. What if negative ions play an important role in that mechanism? What if part of what we’re “getting away from” is the glaring lack of negative ions?
How to Get Exposure to Negative Ions
The best way to get exposure to negative ions is of course going to be the old, natural way. Go to the beach (and play in the water, don’t sit bundled up on the shore). Climb a mountain. Go for a hike. Spend an afternoon reading a great book  in a garden, surrounded by plant life. Swim  underneath a waterfall. Heck, even just stepping outside the stifling stuffy air of your office, turning off the AC and lowering the car windows, or letting some cross breeze into your house will help.
Take a shower. The closest thing many of us get to moving water is our regular showers. And that’s not so bad. Moving water is moving water, and showers do a good job of producing negative ions in their own right.
Another way is to design a negative ion-generating garden, using running water (preferably a waterfall or fountains) and plenty of green life. This method is a mite more involved than simply buying a generator or visiting natural sites of negative ion generation, but here’s a study in which researchers mapped out the distribution of positive and negative ions across a sample garden (PDF ). It should give you an idea for your own garden. The important factor appears to be the presence of running water, since the negative ions were highest right around the waterfall.
For your home or office, I highly recommend a negative ion generator. Many of them aren’t terribly expensive . For, say, 50 bucks you can enrich your stale office in negative ions and filter out impurities to boot. Give it a shot, especially if you don’t spend time in the natural settings where negative ions predominate. If you’re stuck inside all day, bathed in air conditioning, a negative ion generator is worthy of serious consideration.
Or, if you’re handy enough, you could always just make your own ioniser .
Anyway, I’d like to hear about your experiences with negative ionizers (and negative ions in general). Have you noticed anything? Let us know in the comment section!