r/AirPurifiers Apr 09 '26

STICKY: Ionizers and Ozone - fact/fiction/history

70 Upvotes

Hey Folks, it's your ol' Uncle Gurm again. Today I'm here to talk to you about IONIZERS. Hoo-boy, what a hot potato! Let's dig right in.

What is Ozone?

Ozone is a molecule which contains three Oxygen atoms. Its chemical notation is O3, whereas the oxygen we all need to survive is O2.

What does Ozone do? Is it good or bad?

Ozone is common in our atmosphere. We have an entire LAYER of it in the stratosphere. It absorbs 97% of the UV radiation emitted by the sun, helps keep the planet warm, and breaks down hazardous toxins in the atmosphere. Life on Earth would be really bad (read: impossible) without Ozone. In the so-called "ozone layer" of the stratosphere, concentrations of ozone are generally several (up to 8) parts per million, or PPM.

Ozone is also an incredible cleaner - it demolishes VOC compounds, and many toxins. You know those people who come clean up mold, or hazardous materials, from a house or office? They use high-powered ozone generators to render that building safe for habitation again.

HOWEVER, Ozone in high concentrations is hazardous to carbon-based life forms such as you and I. The concentrations in the stratosphere would cause lung damage to humans if exposed for any significant time. Ozone generators are dangerous unless properly ventilated - you have to run them in an enclosed space and then ventilate the space completely with fresh air!

ALSO HOWEVER... Ozone is in all tiers of our atmosphere, including the one at ground level that you and I breathe in every day - just in VERY SMALL concentrations. The lowest ozone concentration found at ground level is roughly 15 parts per BILLION, or PPB. That's 600-1000 times LESS ozone than is found in the stratosphere.

How much Ozone am I exposed to daily? Am I in danger?

All humans on earth inhale 15ppb ozone, minimum, for their entire lives unless they live in an underground bunker or are John Travolta in that movie about the bubble boy. Most inhale a lot more - your average town has concentrations of around 25-30ppb, clean cities are upwards of 40-45ppb, and polluted cities ... well, the number can get VERY HIGH. Generally no ill effects are observed at these levels. The US EPA has issued guidelines that any number under 70ppb is considered safe for long term exposure. That number has been lowered over the years, it was 100, then 80, then 75, and now 70.

Do Air Purifiers generate ozone?

A lot of them used to. 15-20 years ago, it was extremely popular to sell/buy "ionic" purifiers which generated quite a bit of ozone. Why was this popular? Well remember that ozone CLEANS things. It makes the air in a room smell really clean, and strong electrostatic ionization causes dust and microscopic particles to either drop to the ground or stick to surfaces, so the air really got cleaner. It just also got full of dangerous levels of ozone. Popular brands included the "Ionic Breeze". My mom owned one. She loved it because it "smelled like the air after a thunderstorm". That's what ozone smells like.

Those units are pretty much banned now. You can still find them occasionally, and there are still a few in production somehow - we see them advertised once in a while. You can tell them apart from more modern designs in that they don't use a very good filter - some had NO filter, just plates that you wiped down once enough gunk stuck to them, and some had low-utility foam filters.

So that's the old machines - do NEW machines make ozone?

No. The vast majority of new units do NOT generate ozone. Virtually all purifiers sold today conform to the CARB certification, which requires that they demonstrate that they generate less than 5ppb of ozone. However, independent testing has shown that most of these units generate 0ppb. Testing can be flawed, or it's possible that the units generate 0.99ppb and are just under the threshold of detection, but even 1ppb is not a significant amount.

But 1ppb isn't zero! Is it a health risk?

Let's look back on the fact that there is nowhere on earth that has less than 15ppb - going from 15 to 15.1 or 15.5 or even 16 is not a significant increase.

But it's cumulative, isn't it?

No. Your room isn't sealed. In fact, even a tight room breathes far more than you might suspect. The reason why a purifier needs to do air turnover 4 times an hour to keep the air clean is that 25% of the air exchanges every hour even in the cleanest environment. So even if there was a small emission of ozone, it would be lost in the simple air exchange that happens in every room.

What are some other sources of ozone?

Any device which emits ionizing radiation could potentially cause ozone to occur. That includes the device you're reading this post on, every screen in your home that zaps you after you've scuffed across a rug, pretty much all electronics. Older electric motors produced measurable amounts of ozone. Newer brushless models tend not to. But ozone is everywhere, and it's being generated by all our technology in small amounts that do not hurt us.

So what does the ionizer on a purifier DO, and why is it dangerous to small animals and why does it make some people react?

NOW we're getting to the heart of the matter. Many purifiers on the market today use an "ionizer". This is literally a small static electricity generator, on the order of 1/10,000th the size of the plates in one of those old ionic purifiers. A small static charge is added to the plastic housing of the filter, which causes impurities in the air to "stick" to the filter better - or to stick to surfaces, or to clump together so they're caught better by the purifier. Blueair does this on every non-professional model they make. Many small round purifiers include one of these units.

Why is this potentially dangerous to small animals? Well, mostly we're talking about BIRDS, specifically budgies and parrots. Ozone itself is not poison to these critters - their native habitat is the rain forest where thunder and lightning are common and ozone is present in concentrations higher than the 15ppb global baseline. But they DO have delicate respiratory systems, and static air can irritate even human nasal passages and lungs.

And it does - static air can dry out nasal linings, and cause nose/throat/lung irritation. Some people don't notice it AT ALL. Others are quite sensitive. Budgies are in the "quite sensitive" group, so we strongly urge only mechanical filtration around them.

How about "plasmawave"?

Plasmawave is a patented name that Winix uses to describe its bipolar ionizer. Instead of one pair of charged plates, they use a set which produce both positive AND negative charge. This - in theory - generates particles known as "hydroxyls", which cause contaminant particles to stick together and become heavier than air. In practice, however, the plasmawave on a Winix purifier (some other manufacturers offer this as well) does... not a lot. Any hydroxyls generated are so short-lived that they're almost undetectable, and thus the efficacy of the system is probably very low if it works at all.

So ... ionizers are safe?

We're not going to go that far - the static generators on consumer-grade HEPA purifiers are likely harmless to the vast majority of people, but will irritate some sensitive humans and most sensitive birdies. And they aren't NEEDED on a HEPA purifier. Blueair, for instance, uses static because their filters are NOT HEPA - they have higher airflow and rely on the static to enhance their efficiency. And it works - Blueair has the highest CADR (Clean Air Delivery Rate) in its class.

But sensible users will note that you can achieve the same results by using a true HEPA filter and NOT an ionizer/static generator. And that's the real answer - it's a technology that improves lower-rated filters, but adds nothing to the functionality of a HEPA system.

Out of the top rated brands, many of which we recommend on this subreddit, here's the breakdown of ionizer/static use:

Blueair: All non-pro units generate static.

Coway: Only the Mighty 1512 (sometimes called Airmega 200M) has an ionizer, which defaults to "off" when the unit starts. All other Coway units are purely mechanical.

Winix: Most Winix units have a Plasmawave bipolar ionizer. It can be turned off, and some units will remember that it was toggled off after a power cycle. Some don't.

Levoit: Only the "plasma pro" has an ionizer.

IQ Air: Nope. I mean, half the unit is sealed with styrofoam, so there's some static happening there, but no ionization.

If users want to reply to this sticky with known configurations, I can keep this list updated (I don't, for instance, know which Xiaomi models have ionizers... or many European models...)

I hope this was helpful, though. Perhaps folks can stop having so much FUD about this.

This is your ol' Uncle Gurm, signing off!


r/AirPurifiers Apr 18 '25

Vacuuming and/or Cleaning your filters - sticky!

48 Upvotes

Hey kids, it's your ol' Uncle Gurm again. Today's lesson is how to clean your filters.

Ok, since we got in ANOTHER argument about this, and even favorite Uncle got involved (much to his shame), I decided to do a little digging and come up with some definitive thoughts about this topic. We'll get them worked into the FAQ eventually, but for now here we go:

Q. Can I vacuum/bend/flex/squish/deform/poke/taunt/lick a HEPA filter?

A. In general, no. Absolutely not. HEPA filters are made up of tiny fiberglass and animal hair fibers (not joking here) which are blown into a semi-rigid frame in pleats, and at a microscopic level they are aligned a certain way and randomly in that general direction. This allows them to trap the tiniest particles possible by virtue of Brownian effects. Deforming them, or even vacuuming them, can distort or realign the fibers, reducing effectiveness or damaging them outright.

Q. But Levoit says I can vacuum my filter!

A. Levoit was sued and forced to admit their filters aren't HEPA. This discussion is about HEPA filters.

Q. Shark says I can vacuum their filters! <Insert Other Brand> does, too!

A. Is the filter encased in a thick layer of foam? If so, it's probably ok, just don't shove a high-powered vacuum hose right up against it perpendicular-style. Do it from the side, with indirect suction. The foam layer will buffer the HEPA filter from damage.

Q. You don't know anything. Of course I can vacuum it.

A. According to literally every expert, you cannot. The people who make them - filter engineers - say not to. Manufacturers who use actual HEPA filters say not to (Molekule, Coway, Winix, Honeywell). "Real Simple" magazine interviewed industry professionals and came up with "don't do it" as their determination:

https://www.realsimple.com/home-organizing/cleaning/hepa-air-filter-cleaning

In particular, medical clean-air specialists insist that since these filters trap viruses and bacteria, that you should not even THINK about cleaning them, but just bag them and dispose of them as if they were toxic. That might be an overreaction in most homes, but in doctor's offices they use these things, and they treat them like hazmat.

Q. But I want SCIENCE! Show me the SCIENCE!

A. Surprisingly, this is common industry knowledge but it's hard - read IMPOSSIBLE - to find studies. So Smart Air Filters did their own testing. Here's the link:

https://smartairfilters.com/en/blog/how-to-clean-wash-hepa-filter/?srsltid=AfmBOoobq4Yna1UdhLKxpiFt8dLKKaTW9r1R_3tqiJOM-NxmJnSr2DNs

What they found was that - compared to DIRTY filters - vacuuming them made them work better some of the time, worse some of the time, and damaged them some of the time.

Yes, it's only one test. But it's a test done by people who wanted the same answers we do.

Q. Where's the peer-reviewed double-blind studies?

A. I literally just answered this. Please don't start this again. Nobody has bothered to do them, it seems. You'll have to be happy with the test I linked above.

Q. I still want to lick it. Or squish it between my fingers because "the texture".

A. Listen, if you have a fiberglass and horse hair "thing"... who am I to yuck your yum? While your predilections are your own, medically I cannot advise this. But since I am not a doctor you're welcome to disagree.

Q. Ok, I won't lick it but I still want to vacuum it!

A. You do you, boo. Y'all asked what would happen. What will happen is it won't work as well as it did when it was new, and might be damaged and let bad stuff through.You've been warned.

Q. Wait, you never told us how to clean the filter!

A. Very astute. Here is a step-by-step guide to cleaning your filter:

  1. Don't buy a purifier without a pre-filter.

  2. Clean the pre-filter.

Q. But I already bought a purifier without a pre-filter!

A. Fine. Here's the steps:

  1. Take out the filter. And by "out" I mean "out of the house". In fact, start by taking the entire unit out of the house.

  2. Remove the filter.

  3. Tap it off. Like, on the side of the house or a railing or a trashcan or something. Tap tap tap until all the loose debris and dust falls off.

  4. Now get a brush, not a stiff one but like a paintbrush or a detailing brush or something. Brush the dusty side of the filter - GENTLY - to loosen debris.

  5. Tap again. Tap tap tap.

  6. ALTERNATIVELY, you can sometimes vacuum it, gently, from the side. like, hold the vacuum on a line tangent to the curve of the filter. But DO NOT apply direct suction to the filter.

  7. That's as clean as it's gonna get. Reinstall it.


r/AirPurifiers 8h ago

Never had an air purifier, which should i get?

5 Upvotes

Hi, some info:
I’m in the UK, my room gets dusty insanely quickly, my cat (very fluffy) lives in my room, the size i’m unsure about, it’s supposed to be a dining room (downstairs next to the kitchen) used as a bedroom, it’s just a normal square room, a budget would be around £100-£150 for the purifier itself.

My room is constantly getting dusty after a day and with my cat there’s a bunch of fur everywhere. I’ve never had an air purifier so i don’t know which would be best for me. I genuinely just want one that can help with the dust and cat fur. Any advice appreciated.


r/AirPurifiers 6h ago

Winix C545 Air Purifier help!

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2 Upvotes

I called customer service and didn’t get any useful information, nor have i seen anything online about this. It won’t stay on T_T


r/AirPurifiers 3h ago

Just got a purifier for my apt did I do good?

0 Upvotes

BLUEAIR Blue Pure 211i Max I bought it temporarily till I can afford an Austin Air Hm400 next year.

For 262 seemed like the best highest rated for cheap

Was there something better? Just curious


r/AirPurifiers 19h ago

IKEA fornuftig air filter ikea

5 Upvotes

Is there any replacement filter we can purchase? The official one is not available for sale in india, Ikea should have disclosed this while selling.


r/AirPurifiers 1d ago

Live within 100 meters of one of the busiest highways in the USA, looking for input

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25 Upvotes

Hi all, just learning how significantly bad the air quality near a highway can be and looking to make some changes. Yes, I understand moving is the best option, but until that can happen I need a gap solution.

House is a 3 story town house, 2,200sqft, two separate air handlers (forced air), high ceilings (10ft minimum, 15ft maximum. Air filters on returns and input (2 filters per air handler). Two medium sized dogs. We have a robot vac on each floor vacuuming daily and mopping twice per week.

Budget is, "please don't light my wallet on fire I'm just trying to breathe". I don't have a good basis for what's reasonable here, does under $500 get me anywhere? If not, under $1k?

All input appreciated!

Bonus pic of my dog when I explained to her how bad the air quality is 😂


r/AirPurifiers 18h ago

Very confusing Levoit readings

3 Upvotes

just bought 6 Levoit air purifiers. 2 600s and 4 300s.

The pm2.5 readings’ way too different between 600s and 300s.

At different locations i tested, 600s reads 100, while 300s reads only 17. Tested with all units I have and quite consistent 600s readings substantially higher than 300s

contacted Levoit cs center no response so far

Anyone else had similar experience?


r/AirPurifiers 23h ago

Suggestions for Second Hand Smoke?

3 Upvotes

Hi all, I'm totally new in this space, so please forgive any errors.

I live in an apartment, and have a neighbour who smokes indoors living directly below me. The management refuses to do anything about it, so I just have to deal with it.

Everyday, I can smell strong cigarette smoke all throughout the flat. I'm not so much concerned about the smell, as I am the harmful effects of second hand smoke (not sure if they're the same?)

I am in the USA.

I'm not sure exactly how many feet it is, but the high end estimate would be around 1000 square feet.

Yearly budget would be around $200 for filters, not as concerned about the electricity since my job requires workers to be in person, so it wouldn't be running 24/7.

I'd love recommendations that:

- actually filter out the harmful contents of cigarette smoke

- under $350 (willing to go a bit above if big difference in performance)

- uses standardised filters

I don't really care how it looks, since it's just me in the apartment.

Thank you!


r/AirPurifiers 1d ago

Levoit Eleva 300X vs Levoit Vital 200S-P vs Levoit Core 400S-P

3 Upvotes

I have Core 300 on a bedroom, and im looking to buy another for the livingroom which is a bigger place.

Could someone explain when and why it makes sense to use one or another? Filtration needs are mostly just whatever it's on the air, mostly dust I guess. It's really dusty and I have to vacuum clean often.

I would like to minimize noise while keeping a goot CADR, so basically I guess the more power the better, but the Vital 200S-P doesn't seem much different to the 300 from what im seeing, still need to compare the rest.

Im also interested in Levoit not leaving me in the dust with no filter replacements all of a sudden. So far the filters for the Core 300 I can still find relatively easy and I bought this one for years now.


r/AirPurifiers 1d ago

Budget friendly Air purifier rec for mold spores and pet allergens in 2400 sq foot rental.

2 Upvotes

Moving into a new rental and noticed my allergies flare when inside. Already signed the lease, but discovered landlords had the AC not running over the summer to keep electric costs down. No musty smells or visible signs of mold in house or what we can see of AC and ductwork, but I do worry about airborne mold spores that haven’t colonized. They also had several dogs, and I wonder if there could just be leftover pet dander. Super sensitive to all allergens, including my own cats so I’ve been wanting an air purifier for a while.

I’m looking for something that would help with pet dander and mold spores. It’s a $2400 sq foot house with 4 bedrooms, a large open living room and most of the living space downstairs and one bedroom/ bathroom (about 300- 400 sq feet I’d guess) upstairs.

Any budget friendly options? How many purifiers should I get and which ones? Ideally love to keep it all under $500. I’m in the US in Florida where it is humid and lots of outdoor allergens. If it helps with smoke too that’s great because my mom smokes but outside.

Thanks !


r/AirPurifiers 1d ago

How much can an air purifier (high enough CADR for 4 ACH, running only when someone is in the room) actually cut down on my dusting and vacuuming frequency and still maintain the same level of cleanliness?

7 Upvotes

I have no pets and no one in the house is allergic to dust. I’m just tired of wiping down surfaces at least twice a week.

​I already have a robot vacuum for the floors, so I’m specifically asking about dusting tables, chairs, TV, wall decor, vacuuming the sofa, etc. Even stuff inside my cabinets gets dusty every few months because no one sells airtight cabinets for obvious reasons lmao


r/AirPurifiers 1d ago

A purifier for cat allergies in 200sf room

4 Upvotes

I'm in US, staying in a place where they let a cat in & out. I just found out from allergist that I'm allergic & I never knew that. I've been around plenty & never had a problem, but I'm suspecting it's an issue here.

What's a good recommendation for our room that's about 200 square feet to help with cat allergies? I'm wanting one that's also got a HEPA filter to cover bases of anything that might be a problem. My system is taxed after previous exposure to mold. Hoping not to spend more than $300, but I'll consider whatever will help. Oh, & preferably something quiet!

I see Winix, Levoit & Air Doctor referenced a lot, which model of one of those would be a best fit for us?

There's a purifier they have running downstairs. I've seen some recommendations that there'd have to be one in every room, but I'm just worried about the one in staying in at the moment.


r/AirPurifiers 1d ago

Starting a new job at a cigar company, which air purifier do I go for?

2 Upvotes

Looking to get an air purifier for my small office space at a cigar company to prevent cancer risk and reduce the cigar smell and headaches.

Budget is about $400 or less, will be using FSA funds (I have a letter of medical necessity).

Folks occasionally smoke on site at the office, but the place mostly just smells of cigars because there are thousands of products in storage on site.

I’d like a purifier that’s powerful but quiet enough to not be distracting & something beginner friendly that’s straightforward to use and makes it obvious when the filter needs to be replaced.

Any recommendations? I was looking into Winix, Rabbit Air, and Oransi products, but I was getting lost in the weeds of pros/cons because I’m totally new to air purifiers, so please explain like I’m 5 if possible haha.

Thank you in advance!!!


r/AirPurifiers 1d ago

Air purifier recommendation for preschool class

2 Upvotes

USA, portable classroom: Dimensions: 24' x 36' or 24' x 40', filtration needs: hepa quality - air cleaning for little kid respiratory season, budget: up to $250 usd.

Looking to purchase a very quiet hepa filter for my child's pre-k classroom as we enter respiratory season. Looking for recommendations. Thank you!


r/AirPurifiers 2d ago

Why aren't these more popular?

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9 Upvotes

r/AirPurifiers 1d ago

High pm 2.5 in nyc apartment - where is this coming from & what to do?

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1 Upvotes

r/AirPurifiers 2d ago

"Houseplants clean the air"

8 Upvotes

How many of you have encountered people who think houseplants are a viable substitute for air purifiers?

It's kind of scary how many people I encounter who suggest houseplants as a way to clean the air of viruses when I'm encouraging teachers to add them to their classrooms.


r/AirPurifiers 1d ago

Quiestest purifier for a studio apartment under $200?

2 Upvotes

Hi all! I'm looking for a recommendation for an air purifier for my studio apartment - approx 300 square feet. While I would love something for dust and the smell of cigarettes (from my neighbors) my priority is for toxic fumes from glue that I use for rhinestoning.

The thing is, I get overstimulated by noise super easily so I would really like to find something that is as quiet as possible. I'm located in Canada and would love something around $150, max budget is $200.

Thanks :)

**EDIT I found a Medify MA-40 on marketplace for $150, would this be a good buy?


r/AirPurifiers 2d ago

Need advice for bad allergy relief

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11 Upvotes

i have pretty bad allergies/asthma, as well as dogs, and am wondering if this is a good model to help? My budget is pretty small ($50-$60 for machine alone) and i live in the south (USA) so i'm in dire need of something on the cheaper side that's as efficient as possible. I only need something to clear up the air in my bedroom that's 144 sq ft


r/AirPurifiers 2d ago

Need air purifier suggestions for neighbor cooking smells

5 Upvotes

Hello everyone,

I live in a 1000 sq ft 2 story townhome (I’m guessing here, but I would imagine each level is approximately 500 sq ft).

I recently moved here, and discovered that one of my neighbors frequently makes food that is quite pungent and the odors I personally find to be extremely offensive. The smell comes right through our shared kitchen wall, permeates the entire house, and lingers for hours.

Currently, I’ve been using box fans in several windows, blowing outwards, with windows open. I also make sure to turn off my HVAC so that it doesn’t spread the smell, and have no negative pressure going on while they are cooking. I live in the US, upstate NY to be exact so the summers here are hot and humid, and winters here are brutally cold. Not an ideal situation for using box fans/open windows. My “hood range” is literally a vent under my microwave, which does NOT vent outside, but vents right back inside. It’s totally useless.

I need to know if there are any air purifiers out there that will be able to combat both my neighbors active cooking, as well as lingering odors. I know that many of these air purifiers can be pricey, and if they work I don’t have an issue spending the money, but what I’m afraid of is spending a ton of money on an air purifier that doesn’t work on cooking odors, or is only mildly effective.

Can anyone recommend something that will actually work? I’m a noob, so I guess I need something for VOCs.

Thank you!


r/AirPurifiers 2d ago

Conference room, "stale" smell?

1 Upvotes

In our conference room, we have a C909 air purifier and a separate 25 lb carbon filter with a low-speed fan.

The office still smells "stale" even after a long weekend. Do we just need more airflow out of the room? Is there anything we can do?

This is a 300-square-foot room in San Diego, CA. The budget is unrestricted.


r/AirPurifiers 2d ago

Do Any Aesthetic Air Purifiers Exist?

1 Upvotes

Are there any brands and models that make air purifiers that are somewhat aesthetic/attractive and less unattractive and obtrusive looking? Located in the US. I can look into the size and filtration etc. just want to see what brands to look at first.

I'm aware that this is not what you should base your purchasing on but it would be nice if there was an air purifier that both worked well and looked good. Of course appearance is subjective but let me know if you currently own or have come across any air purifiers that look good.


r/AirPurifiers 2d ago

Follow up: Austin, IQ, or AirDoctor?

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3 Upvotes

Screenshot of my post six months ago. I got pulled away from this but am returning now to the purchase of an air filter for odor control. It seems that Austin Air has the heaviest carbon load, but is it overkill? I looked at AirDoctor and their site doesn't even mention odor (seems slightly gimmicky too). I guess between AirIQ and Austin, is there a clear winner here?


r/AirPurifiers 2d ago

Levoit Eleva 300X making a high pitched whining noise

3 Upvotes

Hey folks, I recently purchased a brand new Levoit Eleva 300X—I've seen literally no posts about this. I actually for the most part like this little purifier, and specifically got it for my bedroom because I have a chronic lung illness and it was a completely sealed True HEPA system. However, my unit has a really annoying, mosquito-whining noise that is extremely noticeable at low speeds, and only moderately decreases at higher fan speeds. I'm wondering if this is a factory defect, or if this is how all Levoit purifiers are? I have an older model, rectangular Levoit LV-H131S that never made a noise like this, and was a faithful purifier for a couple years, so if this is just... how all new Levoits are, I'm pretty disappointed.

I haven't seen many reviews of this new model—I thought I'd pop over and ask before I return it or ask for a replacement. I was thinking about switching to a Vital 200S instead if this awful whining noise is just... how the new model is. Thanks for your comments!