Have you ever had a good, deep breath of the air near a waterfall, or perhaps after a thunderstorm? That unmistakably fresh smell is due to ionized air, specifically negative ions, and many are the claims concerning their health benefits. A minor industry has sprung up to capitalize on the interest in ionized air, and while [Amaldev] wanted to clean up the Mumbai air coming into his home, he didn’t want to pay a lot for a commercial unit. So he built his own air ionizer for only about $10.
When [Amaldev] dropped this in the Hackaday tip line, he indicated that he’d been taking some heat for the design from Instagram followers. We imagine a fair number of the complaints stem from the cluster of sewing needles that bristle from one end of the PCB and are raised to 6,000 volts by a fifteen-stage Cockcroft-Walton multiplier. That’s sure to raise eyebrows, or possible the hair on one’s head if you happen to brush by the emitters. Or perhaps [Amaldev]’s critics are dubious about the benefits of ionized air; indeed, some commenters on the video below seem to think that the smoke in the closed jar was not precipitated by the ion stream as [Amaldev] claims, but rather somehow was settled by heat or some other trickery.
Neither of those bothers us as much as the direct 230-volt mains connection, though. We’d have preferred to see at least an isolation transformer in there, or perhaps a battery-powered flyback circuit to supply the input to that multiplier. Still, the lesson on cascade multipliers was welcome, and we found the smoke-clearing power of ionized air pretty amazing.
The smell is ozone, it is rather odd to associate it with freshening the air, or generalized health benefits. I guess if you always use ionizing air purifiers then this association would develop.
Incoming! That’s a warning, there are a bunch of trolls about to reply to my comment without looking anything up to check. ;)
The reason they help clear the air is that the ions stick to stuff floating around, and combined they’re heavier, so stuff falls out the air. Depending on your air quality, that might be a good thing, that might give you cleaner air. But you’re definitely introducing indoor smog to create the effect.
The first mistake people will make in arguing is that they will be excessively credulous of the labels that manufacturers use to differentiate products. They’ll notice that “ionizing air purifiers” and “ozone generators” are slightly different products, when you get those words off the box. But what they won’t realize is that this is just words; an “ionizer” is literally an ozone generator, but in product descriptions, it means a small one. But they won’t use the word ozone, because then people might notice that health professionals advise against indoor ozone generators. As long as they use different words, only a few consumers are capable of researching and understanding the products.
That said, always love to see DIY high voltage generators. Awesome hack!
(I do turn on ionizers in rooms with particulate pollution, if you thought my comment was anti-ozone you read it wrong.)
I used to believe that ozone and ionised air were one and the same. But they are not, one is O3 and the other is O2 but negatively charged with one or more extra electrons. Small amounts of unwanted highly toxic Ozone are produced by even the best designed air ioniser but is usually well below public health standards.
I hsve not researched it, but I guess that you start generating more ozone when you use higher voltages, so electrons have enough energy to separate O2 into separate Oxygyn molecules (which then combine with other O2 molecules to become O3).
I’ve never had chemistry at school, am interested in it, but don’t dare to read much about it because I’ve already got too many subjects to divide my attention too thin…
Smarter Every Day did a video on that involving some scientists, as usual.
Ionizers are basically BS, the amount of Ozone they produce is pretty much unhealthy.
I suspect that you mean “Are Negative Ions Good For You?” by Veritasium, I have never seen a video by SmarterEveryDay on Ionizers. I did not express an opinion that charged ions are good or bad for humans, all I said was that the ozone produced (by a good ionizer) was below the public health standards.
Exactly what I said was “Small amounts of unwanted highly toxic Ozone are produced by even the best designed air ioniser”, and maybe I did not state that the crappy ones, usually large devices with large metal plates which operate at really high voltages and generate an air current, produce mostly ozone. Amazingly enough that appeared to be the device that Veritasium used in his video.
If it is a relatively small device which uses almost zero power with one to four really sharp needles, and you generally can not tell if it is on or off, unless you turn off the lights move your finger near one of the sharp points and see a dim corona discharge, then it is going to be mostly producing charged O2 and N2.
bigclivedotcom has a good tear down video of an OKish one at https://www.youtube.com/watch?v=y7QFJgTjzcc “Inside a Dezac ioniser with active dust collection mat”
Ah, yeah, Veritasium, not SmarterEveryDay, my fault.
But can you actually smell the difference between neutral and charged O2 molecules? Or are you just smelling that small O3 component? My guess is the latter but I’m interested in hearing from someone who knows.
So, basically:
Ozone (O3) is created in small amounts due to the nature of changing the polar state of N and O ions in the air. The high energy-pressure exerted between the charged plates attracts oxygen and nitrogen molecules, confuses/traps them with a central earth ground, and then the field of increased free electrons charges the unsuspecting molecules, adding an election, thus creating anions.
During this process, due to the high energy field, the excited electrons in the molecules occasionally brush against those of another molecule that’s compacted in the field, turning O2>O3. However, due to the phase discrimination, this is a inconsequential bi-product, if the ionizer works (as this one does) through stepping. The “stages” are a series of mildly different voltage states, cascading together at once to create a unified electric field. In general, this very slight difference in overall energy state keeps the field from being at the necessary strength to cause oxygen molecules to bind.
With any static field, however, there are pockets of extra-excited energy that follows eddy currents.
Static field is per definition unchangeable. It may have topological inequalities as a field produced with AC voltages too but they are much better controllable as with AC. Steady, unchangeable field does not produce eddy currents. This is induction property of AC only.
Yes, reminds me of the smell of the lab after firing up the ICP when I ran the foundry lab in my first industry job.
Amazing however, the capabilities of ozone in regards to decontamination. Works wonders in my experience. Just have to make sure to air out the environment prior to occupying again and I’d consider not having certain plastics (I haven’t determined which exactly other than my Prius interior) in the room/site. I’ve heard some FBI offices use a little ozone in the HVAC system post the anthrax scare… not sure the details if only at night or what since hearsay.
On the other hand… too much is not good and I recently watched a video where a novel speaker design emitted so much ozone the inventor (who was also the saleman) literal got sick and had to scrap the venture if I understand correctly.
https://www.youtube.com/watch?v=msE14cWTwKI
The old bar/restaurant type smoke eaters just put metal screens within the air stream with a potential difference between them. If they gave off ozone, they need a cleaning. The idea is that smoke particles are already ionic or at least polar and are attracted to one polarity or the other. You don’t need enough charge to force o2 to o3, just enough electrostatic charge to attract the ionized particles. Some sophisticated units would monitor leakage current and set a service light that the filter needed cleaning. Creating ozone takes power which means there is a finite current flow. The cheaper ones you just listened for the little snaps of arcing when there is too much build up.
I worked on one guy’s invention that alternately charged the incoming particles so they would clump and be picked up by a standard air filter instead of a HEPA-filter.
Perhaps the association goes further back and is more natural than you think.
Rain washes particles out of the air. One encounters the same smells after a lightning storm which usually comes with rain so the two go together even if the relationship isn’t causal.
I’m not sure what you mean by “smog” since its most definitely not smoke or fog the machine is producing. Do you mean pollution?
ozone generators and negative ion generators are the same machine, so I can see how you could get them confused, but they don’t accomplish the same task. Negative ion generators operate much slower and at lower power, and they have a different result. Kind of like how burning and rust are both a process of oxidation, but the speed and energy level of the reaction changes how it impacts the result. Small amounts of collateral ozone are generated by the ion generator, but thats not the intended goal. Air ionizers don’t produce ionized oxygen, they produced ionized air. Ionizing the oxygen part of air sometimes produces o3
My question is about ozone… Is ozone something that will mutate cells? If it does, at what level does it become dangerous? And what DIY can clean the air while leaveing my zone alone with no oh?
Great question. I literally made a comment regarding in a reddit wondering the same earlier today. Thinking there must be research data that can be used to identify sweet spots regarding efficacy of concentration and exposure limits. Also thinking, mainly when using for shock applications, never be present when decontaminating and wear PPE for post decon opening up and ventilating if the post decon process is not an automated process.
That after thunderstorm smell is ozone.
So is the ionizer smell. They’re just small ozone generators.
Not recommended by health professionals, unless you have indoor particulate pollution, in which case it will help it to settle out.
But DIY high voltage is always an awesome hack!
True, the smell of an ionizer is ozone, but the ozone is a by-product. Good ionizers produce less, and therefore have a less noticeable smell.
(also I agree, this is a cool project)
You are not smelling the ozone. That’s the smell of your own mucosal as the ozone get it oxidized.
Also you don’t see hackaday website. You see chemicals in your eyes being decomposed as light from screen hits your retina. Mind = Blown
To be a smartass you first musn’t miss the point.
Do you think that’s air you’re breathing?
Its not decomposition, it’s transition back and forth between cis and trans configurations of chemicals. Still weird when you think about it!
Lol@blazingeclipse
It’s not that weird, because you’re not actually thinking about it. It’s actually ionized atoms carrying charge to small neurons which then amplify electrical signals using other molecules, and creating a sort of feedback effect, which you perceive as thinking. And when I think about this, its quite strange because I’m not really typing this either! It’s my fingers tapping on my cellphone, on a keyboard that only exists in my cellphones memory, but it’s not a real keyboard, it’s just an image of a virtual keyboard, with a tiny motor that makes it feel like I’m typing. Weird!
Isn’t everything fantastic :)
The smell is not ozone, it is soil microorganisms that are propelled into the air by currents generated by falling drops.
That design was common on units I used to play with a number of years ago. No isolation transformer was used in any of the commercial ones I had from the 80ās. 240v in multiplier stack and pointy bits for the output.
I have to say I never got a tingly sensation from them any where near what my MB pros provide….
Ionizers don’t help the dust to settle down – they make it cling to everything. In order to be effective, you need a filter mesh connected to the positive electrode to catch the dust particles. Otherwise they just stick to walls and furniture.
This. I use an electrostatic precipitator at work to scrub metal smoke from an EDM machine’s burning steel operation. The unit has 3 sets of filters that charge the particles to get stuck to what look like oven hood filters.
It really doesnt look very complicated. maybe I can ask my maintenance guy to let me see the electronics next time we have it open.
better on my walls and furniture than in my lungs
Don’t worry, it’ll still do that eventually.
The problem is that the chemistry is far more complicated than any of the commenters here realize. Ozone reacts with other chemicals in the environment including cleaning chemicals, air fresheners, cooking fumes, paint on walls, etc., and can actually increase the amount of particulate stuff in the air.
I did a bunch of research on this topic when I was looking at making an electrostatic precipitator for nanoparticle exhaust from a 3D printer (previously featured as a fail of the week). I abandoned the project when it was nearly complete because I kept finding papers that showed that ozone creates more problems than it solves, at least if people or pets are around to breathe the ozone containing air.
https://hackaday.com/2019/07/23/i-love-the-smell-of-abs-plastic-in-the-morning/
And don’t make the mistake of thinking that if something removes odor from the air, or makes it smell “fresh”, that the air is cleaner. There are plenty of harmful things that have no odor or even smell good.
This is what I came to ask, could it be used to clean up 3d printer ‘exhaust’.
I get what you are saying but we have people here claiming that this isn’t so much producing O3 as it is ionized O2. If that’s true might you have given up prematurely?
You don’t want ionized dust sticking to your walls and furniture, because it’s a pain to get it off again. It’s a whole other sense of dirty when the dirt has a tendency to chemically react with the surfaces.
Besides, since there’s a continuous influx of dust into the apartment, then there’s continuous ionization of said dust, and you’ll have a continuous supply of ionized dust to breathe before it finds a chance to stick to something else, which is worse than breathing just dust.
Your right about that. I had a common US made simple NI generator in the 80s . Worked good did not produce ozone had an adjustable pot for output which also worked. It set on a dresser for about 6 years humming along dispersing neg ions . But one day we moved the dresser to bring in some new furniture. WoW when we started to look at the wall with the dresser gone it was obvious where particles were going. We did Not smoke in the house that would have been much worse. So it was repaper walls and paint the ceiling..
Sigh… that made me a believer in the particles need a place to attach.
I toyed in my mind about aluminum foil sheets on back wall or opposed wall but that was vetoed by my then wife #2…
Oh well being wife less now only dogs and cats here with me now and I feed them the good stuff so they vote with me,, lol
Actually thinking about making my bedroom one Big Faraday cage just to attenuate the signal. That aluminum foil hat is uncomfortable to sleep in…
And neg ions,, I think Iām going to build a nice recirculating water fall.. ions natureās way!
In this case all..
Stay Negative..š
Fun fact! Lungs are included in said “everything”.
Which isnāt much help for most people, but is helpful if you get asthma from dust.
Of course, reducing the sources of dust is much better (e.g. HEPA filters in vacuums).
True, the smell of an ionizer is ozone, but the ozone is a by-product. Good ionizers produce less, and therefore have a less noticeable smell.
(also I agree, this is a cool project)
this was a reply. hackaday comments are being weird again.
One of these should be glued to the head of anyone who vapes.
Can rivets be used instead of glue, don’t want to add any bad chemicals to their system.
No, rivets will hurt them. Hot glue is only about boiling point, and it sticks really well to skin. Its also cheap, so there’s that too.
Oh, I dunno about hot glue being that cheap. Homeless Despot here wants more than a buck per stick (for the good stuff).
Roofing nails are less than half a cent each.
No need to be brutal or inhumane! Simple plastic bag to contain all the smoke inside theirs body is elegant and sufficient.
You’re an idiot.
The lady doth protest too much, methinks..
I’m not sure those two tiny resistors would hold off 6000 volts. The circuit traces are right next to each other. HV design is an art, and a science.
If you had read the article (or know about those voltage multipliers), then you’d know that each step of the multiplier only sees < 500V.
If you examine the schematic or read the description, it’s should be obvious that the two output resistors R1 and R2 in series must hold off 6000 volts in the event of a short on the output.
Those poor 1206 resistors are only good for 200 volts each. They’ll promptly arc over at 3kV each.
Further, they would be dissipating nearly a watt each during a short. They’re only rated a quarter watt.
But luckily, the author ingenuously designed the C-W multiplier to be incapable of sustaining that kind of current, so the voltage would collapse over a couple of seconds and prevent the resistors from overheating. But they would have already arced over and laid a nice carbon track to conduct over instead, so it’s moot anyway…
I wonder how that LED feels about having 300 volts reverse bias on it, 50 times a second.
It should feel safe with those 2 51k resistors next to it.
2 mA for a led on 230Vac inded checks out to be 4KWh /year, and if that costs $0.05/year where he lives then his electricity is very cheap. Here in the Netherlands a single KWh is around 25 Euro cent.
Just using a single resistor to drop all that voltage is also a bit dubious. Most SMD resistors are rated for lower maximum voltage. Probably better to use 3 resistors in series. (which also spreads the dissipation per resistor).
A Neon lamp would seem more logical, or simply put your LED in series with one of the diodes of the Wallie Crotch Craft voltage multiplier itself. This would also vary the LED current (& brightness) with the current through the multiplier, which gives an indication of it’s working.
When you look at:
https://en.wikipedia.org/wiki/Electrostatic_precipitator
then you’ll see he “forgot” something.
Normally these precipitators have something with a lot of surface area behind the part that charges the air particles, which chatches the pollution, instead of letting it settle on the floor and furniture near the aparatus. To be effective the “home” versions also have some kind of fan to put much more air through it.
You can use a capacitor dropper circuit to reduce the power drain for the LED. Make sure the capacitor is a “X cap” ( used for EMI filters) that is safety rated to be connected across the AC rails.
https://bobparadiso.com/2015/02/03/capacitive-dropper/
Ozone generators are used to help get rid of smoke smell in a house after a fire or other misadventure. Like when someone forgets something on the stove. A UV spa ozone generator can accomplish this too while the place is empty for a day. Helps a lot. Still have to wipe the walls and ceilings though.
For that sort of thing I think they’re doing a rapid oxidation of the aromatics as much as particulate precipitation.
Might want to consider put in a low current fuse in series when you connect circuits directly to the AC outlet.
One of the failure modes of a ceramic cap is a dead short.
I have years of experience experimenting with negative ion generators going back to the late ’70’s when the most popular model was a small pedestal with “copper fuzz” on top. Here’s my opinion:
First, I swear negative ions work to clear the air. I had a girlfriend who smoked a lot, and the -Ion-gen kept the kitchen fairly fresh.
Second, the charged particulates will build up on your walls. When we got tired of trying to clean off the yucky brown stains, we simply hung big sheets of news print on the nearby wall. We could make diagrams and leave notes on the paper, and it was easy to tape up new stuff to protect our walls.
Third, KEEP IT AWAY FROM ELECTRONICS!!! My girlfriend wrecked a stereo system and a fairly expensive Marchant electronic calculator my moving the -Ion-gen too close. Those particles will penetrate any electronics….
Fourth, check out the specs to determine which generators produce more negative ions instead of ozone (O3). O3 is not healthy. Free radicals continually ingested as O3 will eat your tissue. Don’t test this for yourself; look up research sources.
Fifth, a bubbling fountain near your bed, or an aquarium with a good aerator, will make you sleep better and may be just as good as most other negative ion generators.
Sixth, IMO the best negative ion generators have a fan that circulates a good volume of air into and out of the generator, toward a charged screen that actually traps the ionized air and attached pollutants. It needs cleaning, but it is better for your electronics and preserves your curtains and walls.
A real ozone generator (and maybe some food-grade Hydrogen Peroxide 35% or better can make keeping a hot tub or swimming pool clean and algae-free a lot easier. A strong ozone generator under a dock is a great way to offset the effects of oil and gas pollution in the places where you keep your boats.
There are hundreds of DIY projects for negative ion generators and ozone generators. Just make sure you what you are creating and measure the output for consistency.
Wow! What a crappy job of typing I did! Sorry! (I blame it all on staying up all night working on a Python project. I should have realized that if my code is coming out garbled, so is my English.)
Any way, the last warning was that you should “know” what you are building and test the output.
Ionizing air with a filter after it to sweep up particulate matter works great! Don’t then filter the ozone-rich output through your lungs.
Did I miss anything?
From the schematic it looks like the last stage is wasted, the high voltage is taken from one stage earlier than the last one.
Perhaps he tapped it out there because the voltage was too high, and the components down the line weren’t dealing with it?
I so wish I had the acumen to build something like this – I’ve in mind a filter for my cigar room. The hepa+carbon work ok. Putting an ozone gen in the room at night after I’ve had a cigar also helps a lot. But a BOX built around a 12″ fan… I envision using regular furnace type filters – 2 before the fan, then an ion generator, then 2 more filters. right after the filters would be the positive charged screen…. anyone living in north atlanta burbs?? :)
I built something like that decades ago for my dad. He said he could feel the difference. Could also see the difference as ‘dirt’ started to collect around the probe