Talk:Air ioniser

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[edit] Comments

A negative ion generator (ioniser or ionizer) is not the same as an ozone (O3) generator although some ionisers do produce a small amount of ozone as a by-product. So to say that there are two types of ioniser and define that distinction by either ion production or ozone production is entirely incorrect.

The second paragraph is also incorrect. Whether a room is closed or open has nothing to do with an ionisers effacy. Ions live a very short life and the distance they travel is entirely down to the device emitting the ions. The more powerful the device the further they will travel. During their brief journey they will attract other positively charged molecules to them and form clusters, eventually falling from the air. Depending on the environment, they will also be stripped from the air by such things as metal ducting and monitors or TV sets. Those ions that remain in the "small" or "light" state are capable of being ingested by humans. These "small" ions will only exist at a very close proximity to the generator.

Do you know of some reliable references that we can use for this article? -Willmcw 11:51, 21 Dec 2004 (UTC)

Man. It is impossible to find realistic descriptions of how these devices work:

That last one looks good. Both the scientific and the practical issues seem to be handled accurately. A couple of those links go to industrial products. While their use as home air cleaners is subject to controversy, their use in industry for special purposes is accepted. One link goes to a ionizer-based (electrostatic) air filter for a forced-air system, which we should also mention and which are less controversial. Sharper Image has sold many ionizer based "fans" which move air silently without any ffan blades. I think their machine neutralizes the ions before they are omitted. Due to its commercial success it might get a mention. [1] Thanks for doing this research. Cheers, -Willmcw 21:13, July 18, 2005 (UTC)

It seems to me that to get this article into a useful and neutral state, it should be rewritten into three main sections. The first should explain what these devices are. There seems to be little dispute on this page that these devices (a) generate a negative electrical charge, (b) cause some dust and bacteria to be removed from the air of a room, and (c) lead to the creation of a certain amount of ozone. The second section should document the claimed health benefits, including the basis for the claims, substantiation and so forth. The third would list criticisms of the devices, including problems with the claimed benefits and also the possible negative effects (such as the creation of ozone). Since there is obviously no consensus on the ozone level issue, the page should say as much, with citations to various government ozone regs and the CU report.

Also, the article should be updated to include the fact that Sharper Image (the main purveyor of these devices in the U.S.) is now marketing an add-on to their devices which claims to convert the ozone back into oxygen. mpmason68 15:45, July 9, 2006 (UTC)

[edit] Types of ions

http://www.webmd.com/content/article/65/72756.htm?lastselectedguid=%7B5FE84E90-BC77-4056-A91C-9531713CA348%7D This article espouses the claim made in this article that negative ions like those after thunderstorms and beneath waterfalls increases well-being according to research.

Are there really two different kinds? I think "creating air ions" is exactly the same thing as "creating ozone", since the ionic oxygen quickly recombines with oxygen molecules to produce ozone. Then again, I don't really remember my chemistry. - Omegatron July 2, 2005 20:39 (UTC)

Some of this is left over from what was clearly an advertisement for a particular ioniser that claimed it emitted a special kind of ions. This article could use a careful review by an editor knowledgeable in chemistry. -Willmcw July 2, 2005 21:42 (UTC)

There are indeed two types of ions: Cations, which have a positive charge, and anions, which have a negative charge. But there are more than two types of marketing nonsense... I used to work on negative ioniser designs years ago, with a bias towards the medical applications of same, and though a lot of people would show an improvement in wound healing rate or reduction in wound scarring, some users would see no benefit, and some users would report a worsening of symptoms. For the latter group a limited degree of success was sometimes to be had by the trusty sci-fi standby of "reversing the polarity" to produce positive ions. This is fairly simple to do with the standard ioniser design that utilises a Cockcroft-Walton ladder to produce the required high voltages. -Midgemagnet Dec 6, 2005, 17:22 (GMT)

To correct Midgemagnet, it is Cations, which have a negative charge, and anions that have the positive charge -Guest Jun 2, 2006, 18:58 (GMT)

Not true. Midgemagnet's statement was alright: cations are positively charged and anions are negatively charged. These two are sometimes confused by people due to the fact that anions are attracted by anode, which is positively charged and cations are attracted to cathode, which is negatively charged. Natrij 20:19, 11 June 2006 (UTC)

Actually, anodes and cathodes can both be either positively charged or negatively charged. It only depends on the direction of the current. In a battery acting as a power supply the anode is the negative end of the battery, but in an LED (that is in forward conduction) the anode is the positive end. In either case, electrons are leaving the anode. So, an anion (negative charge) is only attracted to some kinds of anodes. -Minipie8 02:22, 28 June 2006 (UTC)

[edit] Patents

Kronos Advanced Technologies supposedly makes fan replacements that work on this principle:

U.S. Patent 6,919,698  July 19, 2005 Electrostatic fluid accelerator for and method of controlling a fluid flow

U.S. Patent 6,888,314  May 3, 2005 Electrostatic fluid accelerator

U.S. Patent 6,727,657  April 27, 2004 Electrostatic fluid accelerator for and a method of controlling fluid flow

U.S. Patent 6,504,308  January 7, 2003 Electrostatic fluid accelerator

Others:

Sharper Image Corporation

U.S. Patent 6,911,186  June 28, 2005 Electro-kinetic air transporter and conditioner device with enhanced housing configuration and enhanced anti-microorganism capability

U.S. Patent 6,908,501  June 21, 2005 Electrode self-cleaning mechanism for air conditioner devices

U.S. Patent 6,896,853  May 24, 2005 Personal electro-kinetic air transporter-conditioner

U.S. Patent 6,713,026  March 30, 2004 Electro-kinetic air transporter-conditioner

U.S. Patent 6,709,484  March 23, 2004 Electrode self-cleaning mechanism for electro-kinetic air transporter conditioner devices

Zenion Industries, Inc.

U.S. Patent 6,897,617  May 24, 2005 Method and apparatus to reduce ozone production in ion wind device

And the exact opposite device, a generator charged by wind:

U.S. Patent 4,206,396  June 3, 1980 Charged aerosol generator with uni-electrode source

[edit] Dangers of Ionisers not mentioned.

Hakusa - Wiki addict: 08:31, September 10, 2005 (UTC) I was thinking of adding them, but thought I would check it in the discusion page first. I went to my school library and borrowed a Consumer's Report May 05. In it I read an artical about how ionizing air filters are hazzardous to your health. How while having one in a spacious house was better, but putting it close to a chair or social area like suggested could be very bad. Appereantly ions are toxic: somthing I remember from Bio I. Now I won't quote things from the entire magazine, and if you really care you can go and read the artical yourself. I did however notice that the article mentions the consumer's Report being unfavorable, but it doesn't mention what they said, or anything I just said. Why?

I believe they create ozone, which is poisonous and kills bacteria, but is also poisonous and kills people.  :-) It does say this in the article, but the article needs work. If you could add some information from the CR artice that would be great. — Omegatron 14:49, September 10, 2005 (UTC)
Hakusa - Wiki addict: 20:17, 14 September 2005 (UTC) I was gonna do it, but I don't have the time right now. Sorry.
I actually read the paper copy of the report. The beef was "unacceptably" high levels of ozone from a vast majority of the ionizers. They also only marked two as decent filtration units out of however many they tested; I can't remember which specific models. Really good units have a ion collector behind the particle collection grid to pick up any stray charged particles. -- Toastydeath 17:51, 29 June 2006 (UTC)

Midgemagnet 17:24 (BST) 6 Dec 2005. Indeed; I have added references to the dangers of ozone in the main entry. Claiming health benefits for environmental ozone generators is just dangerous misinformation.

[edit] ionic vs ozone

From chemistry lessons, it has been taught that ions are identified as those pesky 2-letter names with the 2+ and 3+ superscripted next to the metal name: Fe2+ with the 2+ superscripted to show iron ions, Cl- with the - superscripted to show chlorine ion.

Ozone on the other hand is a molecule, created by a combination of 3 oxygen atoms (O3 with the 3 subscripted). Ozone is likely to generate radicals which have tendencies to be oxidizing agents or in other words be corrosive in manner. A short read up on the ozone layer in school textboks will give you a general understanding of what ozone is, how it is formed naturally and why the ozone layer is thinning out at areas above the polar caps.

Whereas most air purifier companies use mechanical filtration, some air purifier companies believe that filtering the air inside the room is not enough. Instead, they manufacture air purifiers which generate negative ions to interact with the positive ions in the air. Someone must have figured out that pollutants in the air, including tobacco smoke and even dust, naturally has positive ion charges. Thus, the generation of negative ions to cancel out these hazardous pollutants, making them falling to the ground and out of the air we breathe in, is the right way ( at least to them ) to purify the air.

Regarding ozone generators, the idea is that ozone is produced from a TiO2 plate by ultraviolet light. These ozone molecules have the oxidising power to kill off airborne pathogens which is good news for us and bad news for the microorganisms. However, since ozone has that effect on bacteria and viruses which are living organisms, wouldn't they have the same effect on humans as well? Is it safe for us humans to be exposed to these ozone molecules every single day for long hours every single time? Some of these air purifier users stated that they smell the bleached smell which they themselves identify as ozone, whilst others testify that all they smell is fresh air.

Hope this information helps. Sylee 06:15, October 16, 2005 (UTC)

Hakusa - Wiki addict: 04:01, 17 October 2005 (UTC) That sounds about right, but Consermers Report sais that you will breath in ozone, and it is toxic.

Yes, ozone is toxic. I'm interested in whether these devices actually output ions. It's difficult to say, really. If they put out only negative ions, for instance, then the device would continue to become more and more positively charged. If they pumped the charge out of a ground wire, though, they would be making the Earth itself positively charged, and maybe that would be the way the ions stick to dust and then the dust is attracted to other objects. I wish I knew more about the properties of charged particles in air. — Omegatron 04:19, 17 October 2005 (UTC)

I'd like to help with this article but I can't say I know any more about the subject than any other editors here. I've changed the template because there doesn't appear to be any actual disputes. Hopefully we'll get an expert soon! --Eirinn 12:12, 23 October 2005 (UTC)

Well, I'm a physicist, and this whole article looks like a lot of BS to me. Regards.

Midgemagnet 17:27 (GMT) 6 Dec 2005. I'm an electronic engineer, and I used to design ionisers (comissioned, I hasten to add). I agree there is an awful lot of BS attached to ioniser lore, and bad designs can produce nasty levels of ozone. However, many people experience real health benefits by having one running in their bedroom at night, and I've seen some rather neat research with hospital patients (operation wounds, large burns) where direct application of a high negative voltage and local exposure to negatively ionised air noticably speeds up the healing process in most cases.

I've taken the liberty of claiming expert status (in the absence of anyone better qualified), and have hacked the article into some sort of approximate shape. Needs more work to be a proper reference though.

[edit] Problems with current version

Hey guys. I'm going to try and update this with answers to all these questions, and leave it to the experienced wikipedians to update the article as they see fit. I'm going to get positive/negative mixed up a lot because they mean different things depending on whose perspective you are looking at it from. Please forgive me if i flip them once in awhile. Also, in some of this, remember that voltage is a potential for flow - it does not necessarily mean that having a "charged plate" indicates a pile of extra electrons or a deficit. It's just describing what the system wants to do, not what it is doing. -- toastydeath 69.138.207.55 07:38, 29 June 2006 (UTC)

I got my physics messed up on the exact interactions - there's no current flow, anywhere. The atoms pick up energy as they go through the EM feild around the corona wire, and eventually pick up enough eV's to emit an electron. I'm going to go back and modify all my responses to reflect this. Also, pardon the different IP. I'm at work. -- toastydeath 209.122.172.254 14:48, 29 June 2006 (UTC) Addendum: O hey, now I'm a real user. Toastydeath 17:41, 29 June 2006 (UTC)

  1. a device which ionises air.
This isn't a problem, that's really what they do. -- toastydeath 69.138.207.55 07:38, 29 June 2006 (UTC)
  1. But do the ions escape into the room or do they discharge inside the device, leaving only ozone and NOx to escape into the room?
Most of the ions hit the collection grid and become part of the device itself. Some of the stuff gets out, and then you smell ozone. -- toastydeath 69.138.207.55 07:38, 29 June 2006 (UTC)
  1. Despite dubious marketing claims to the contrary, ionic wind plays no part in the process, as may be evidenced by the tiny breeze near the ioniser emitter.
True. If NASA and ion thrusters are having a hard time getting signifigant ionic wind, then a dinky $100 air purifier isn't going to be knocking anything off your desk. -- toastydeath 69.138.207.55 07:38, 29 June 2006 (UTC)
  1. If there's a breeze generated by the electronics alone, then how is that not an ionic wind?
  2. An air ioniser also generates negative ions by exposing air to a high negative voltage
I don't see what the problem with this is. The positive (voltage wise, indicating flow direction) electrode kicks a (negative electrically) electron off an atom, which makes the atom (electrically) positive. The now positive atom is then repelled by the positive wire, which is sucked into the negative collection grid. -- toastydeath 69.138.207.55 07:38, 29 June 2006 (UTC)
  1. Can the device expel negative ions continuously into the air without becoming charged? Is it replenishing the missing charge by connecting to the ground? Do the expelled ions then travel back to the earth to complete the circuit? — Omegatron 19:13, 6 December 2005 (UTC)
The air is becoming charged; that is the principle mechanism on which these devices operate. The electron that gets emmitted from the ion gained energy by passing through the high voltage EM field surrounding the corona wire. Once the energy in the field has been transferred to the ion, the transformer draws more current to move the field back to it's origional strength. -- toastydeath 69.138.207.55 07:38, 29 June 2006 (UTC)

Midgemagnet 21:03, 6 December 2005 (GMT)- in reply:

1) Ionisers create ions by either adding electrons to atoms/molecules (giving negatively charged anions) or stripping electrons from atoms/molecules (giving positively charged cations). It's the electric field strength that does the ionising. The emitters on ionisers are invariably pointed (like a needle) or bristly (like a carbon fibre or wire brush) as electric charge concentrates more on the sharp area of a surface, and so the electric field strength near a sharp emitter will be quite high, and any atoms that stray too close will be ionised.

They only strip electrons in this style of device. -- toastydeath 69.138.207.55 07:38, 29 June 2006 (UTC)
In order to generate a strong potential gradient you would need a strong potential difference, right? So there is a positive electrode in there somewhere. So the negative ions would go right to the positive electrode and discharge, wouldn't they? — Omegatron 21:54, 6 December 2005 (UTC)

2) The strength of the ion wind from a domestic ioniser is feeble, and would play a negligible part in shifting air about a room. It does, however, play a small part in keeping the air local to the emitter turning over, so in this respect it is useful in raising the ionisers efficiency, but the wind itself doesn't extend beyond a few centimetres. A draught through a keyhole would be many times stronger.

3) Yes, the ioniser case may become slightly charged. I've seen early (expensive) ioniser models in wooden cases with rubber feet giving people static shocks from touching the case. Wood is a poor insulator, BTW, as well as a poor conductor. But the case will never become as charged as the emitter, and as long as the emitter is clean the ioniser will function as intended.

There isn't necessarily a return circuit for the emitted electrons from a negative ioniser. They just attach themselves to atoms and float about.

But you can't just suck electrons out of an object forever. There has to be a return circuit of some type, or the ionizer would just become more and more positively charged until it no longer worked (because it would be too positively charged for any negative charge to escape from it).
The power supply creates a large voltage differential between the corona wire and the collection plate. Remember, a voltage just indicates what will happen if the electrons are given a path to flow (it's a stationary electromagnetic field if no current is flowing). This difference becomes so great that, like in your television or in a plasma torch, the corona wire deposits enough energy into the nearby molecules to kick an electron out of some poor atom's valence shell. Then, our adventureous electron goes flying at very high speed out into space. The poor atom (hopefully part of a dust mote) is now an ion, and is at first repelled by the corona wire and then attracted to the collection plate. The ion's life is determined by the actual electrical properties of the material that got charged. Highly reactive, short lived ions are called radicals. Additionally, when the ion contacts the collection plate, it assumes the same charge as the plate, effectively becoming part of the collection grid. That's why they work when they're covered in crap. -- toastydeath 69.138.207.55 07:38, 29 June 2006 (UTC)
Note that I'm not a physicist or chemist; just an electrical engineer, so my understanding of the behavior of ions in air is not very good. — Omegatron 21:54, 6 December 2005 (UTC)
There seem to be different types of air ionizers and different theories of how they work. Someone who knows should really update the article. The only undisputed facts I can gather are:
  • The devices involve high voltages
  • They create ozone and nitrogen oxides, which kill bacteria, but are also toxic to people. Whether this is a side effect or the intended effect is disputed.
Unanswered questions:
  • Does the device "purify" the air in other ways, like removing dust and bacteria from it?
Only if the ion hits the bacteria and kills it (i.e., floats through the apparatus). Otherwise, it'll just hang out as part of the collection grid. Yes, dust is removed from the air, along with anything else that happens to float past. -- toastydeath 69.138.207.55 07:38, 29 June 2006 (UTC)
  • Does the device involve two oppositely-charged electrodes or only one electrode that is at a high voltage relative to the Earth?
Two electrodes. The corona wire and the plates are on the positive and negative side of the power supply. -- toastydeath 69.138.207.55 07:38, 29 June 2006 (UTC)
  • Are the dust particles attracted to the other electrode (how does it stay clean?) or are they charged and then attracted to other neutral objects in the room? (I've heard rumors of stains on the walls near these machines.)
Ionization only goes one way in this case - it kicks an electron off an atom. Anions (negative ions) require a different process to produce that I'm not familiar with. -- toastydeath 69.138.207.55 07:38, 29 June 2006 (UTC)
Actually, I have heard that the answer is that they don't stay clean, for what it's worthJeremy RBC 00:16, 31 August 2006 (UTC)
  • If the device is emitting ions into the room, which are then attracted to the Earth (or other objects in the room), are they positive or negative ions? Can it emit both at the same time? (Do ions in a neutral fluid rapidly move towards oppositely charged objects and neutralize, or are they slowed down by the collisions with neutral particles and only slowly drift towards other objects? Would a positive and negative ion neutralize on contact, or does it depend on other factors?)
See above. They're all down one electron. The ions want to either react with things, or gain an electron in some other way. Eventually, a spare electron will be found on something and it will no longer be an ion. Ions themselves will float around until they find either a strong electromagnetic field to move them, until they react with something, or until they gain an electron back.
It's actually more complex than it seems, and only physicists or chemists who really understand ionization and electrohydrodynamics really know what's going on. (And I am not one of them, obviously.) — Omegatron 17:13, 24 February 2006 (UTC)

I've been doing some research on air stuff over the last couple of months, and I think I understand a little bit here. On the other hand, I am a total newbie (but I 'did' read through the relevant wiki background). I'm going to try and clear some things up in the article about the ozone, but here's what I know about ionizers:

  • ASHRAE and the relevant U.S. medical societies have yet to embrace ionizers because they just aren't as effective as filters and ventilators are at removing junk from the air.
    • The fundamental problem is that the electrostatic plates lose efficiency whenever they get loaded, save for the really nice ones (which tend to be much more expensive than a filter or ventilator solution would be).
  • Many ionisers produce ozone, which absolutely is toxic.
  • I believe that just about every major HVAC system manufacturer makes some sort of ionizer for residential HVAC systems. It's typically a part of the filter box, and is considered an add-on. Jeremy RBC 00:16, 31 August 2006 (UTC)
    • Strike that, I meant electrostatic filter for the major manufacturers. Anyway, I went through and made some major changes. I think this should be a little more reference-grounded now.
    • A bunch of those claims were dubious at best. I moved them to a "manufacturer claims" bullet point in the criticism. If anyone has a shred of credible evidence for any of those points, by all means move them to the main section (with references and better explaination of how they could possibly be true). Jeremy RBC 03:21, 31 August 2006 (UTC)
One other thing (I commented it in the article, but wanted to bring it up here). That second sentence seemed to say that ionizers make particles with both + and - charges concurrently. That doesn't seem possible to me, since it'd just be a neutral particle. Not that I don't think a ionizer salesman wouldn't use it as a selling point (dehydrated water, anyone?), but I want to be sure that I didn't change the original intent of the statement.
As rewritten, it says that ionizers can be either/or (i.e. -, +, or 50%/50%). Is this right? If so, I'd say leave it where it is. If not, I say revert it and move it to the criticisms section with an explanation of why. Jeremy RBC 18:08, 31 August 2006 (UTC)
No. It would be creating both negatively charged particles and positively charged particles, from each electrode. This would create ozone and attract dust just like the other types, before the particles could "find" each other and neutralize. I don't know what happens in real life systems, though. No one here seems to know what's really going on. — Omegatron 19:12, 31 August 2006 (UTC)

[edit] name wrong

http://en.wikipedia.org/wiki/Water_ionizer <<see plz Ionizing Ionize http://dictionary.reference.com/search?r=2&q=Ionizer http://dictionary.reference.com/search?q=Ionaser =RETURNS INVALID Main Entry: ion�ize Variant: or chiefly British ion�ise /'I-&-"nIz/ (probably brits editing?) Results 1 - 9 of about 10 for ionaser. Google Results 1 - 35 of about 293 for ionazer. Google 0 results for Iionasers Google Results 1 - 100 of about 434,000 for ionizers Google The name is Ionizer not "Ioniser", and the article whould either point out that benefits of ionizing is zero,or there is some effect(like the bacteria case,they just end up on surface near ionizer)and if its better then air filters which clear the dust and not make it precipiate on surface.

This need some category on Junk science devices/paranormal effect devices/deus ex machina or something.I'd better buy a air filter( a purifier,hopefully HEPA compliant)

"Ioniser" is the British spelling. We use both spellings here, depending on the subject of an article and who contributed to it first. — Omegatron 15:30, 29 January 2006 (UTC)

That is the dumbest thing I have ever heard. Use "Ionizer" , "Ioniser" isn't even in the American Heritage Dictionary. Spelling it "Ioniser" effects the integrity of the website you dumbshits.

The correct word is "affects" in this context. You might want to look at the usage note for "affect" in the American Heritage Dictionary. — Omegatron 15:51, 31 August 2006 (UTC)
I replied on your talk page. — Omegatron 18:24, 21 July 2006 (UTC)

For the record, I'm an American, I think the title looks weird, but I'll still revert any attempts to change it. Our policies exist to prevent stale, pointless arguments like this. — Omegatron 19:18, 25 July 2006 (UTC)


  • That is the dumbest thing I have ever heard. Use "Ionizer" , "Ioniser" isn't even in the American Heritage Dictionary. Spelling it "Ioniser" effects the integrity of the website you dumbshits.

I just have to say this is the most ignorant comment I have ever heard or read. So because it isn't in your precious American dictionary, it doesn't exist? And the use of profanity hardly strengthens your argument either. No wonder Americans have the reputation overseas of being loud, ignorant and brash; with every stereotype there is always a grain of truth, and clearly the author of this comment is the grain.User:Jaganath 21:48, 16 August 2006 (UTC)

Since you're new, you should know that in general it's better to just ignore people like this.  :-) — Omegatron 15:51, 31 August 2006 (UTC)

[edit] Dubious

Despite dubious marketing claims to the contrary, ionic wind plays no part in the process, as may be evidenced by the tiny breeze near the ioniser emitter.

How is the presence of wind evidence against ionic wind?? — Omegatron 18:36, 31 May 2006 (UTC)
Yeah, I don't get that either. However, we're talking about magnetic forces on the level of static on a CRT TV screen. It's not going to make wind. Jeremy RBC 03:21, 31 August 2006 (UTC)
But "ionic wind" just means a movement of air caused by electrostatic forces. Breeze or gust or whatever, if the air is moving, it is an ionic wind. — Omegatron 15:54, 31 August 2006 (UTC)

[edit] Advances in Technology - German ionisers

New ionisers from Germany uses the DBD corona system to produce negative ions, but they are now able to control Ozone emission. They carry the TUV and GS certification [German Safety] and the new tecnology is patented [dpma.de] in Germany. They are now fitted into airconditioners, fridges and even tumble dryers. EPA is lagging behind the EU and Japan again. toyo

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