Can An Air Purifier Make You Sick? Here’s What To Know

Update: Looking for information about air purifiers & EMF radiation? You can see my new post about purifier EMF facts & myths here.

While the right air purifier can improve the air quality of your home, some people may wonder if they can make you sick.

Maybe you’re here because you’re asking yourself, “Can an air purifier make you sick?

When it comes to air purifiers, there are so many brands, types, and models, that make a lot of claims and have different kinds of air cleaning technology. But can they actually make your health worse?

Read on to find out what you need to know.

Infographic – Air purifiers and your health

Can air purifiers make you sick infographic

Why do people think air purifiers cause sickness?

Air purifier sickness confusion image
Because they’re such a popular product, there’s a massive amount of information and different terms used out there. A lot of it is either misleading, factually incorrect, or just plain confusing.

One thing you might hear about air purifiers is that they produce ozone or a by-product under different names (like “ions” and so forth).

Some are, in fact, not good for you.  Some products out there like ozone generators are sold as “air purifiers” when in fact they’re hardly effective and can cause problems.

In those cases, they’re advertised as creating an effective air cleaning air molecules (ozone) that is safe and naturally occurring in nature, but this isn’t the case. The ozone emitted by those types of air purifiers is the same as any other kind of ozone – and just as much of a problem.

Bad products can give good products a bad name due to the confusion and having consumers misunderstand how safe, effective purifiers really work.

What a mess!

Which types of purifiers are good and bad, and why?

The basics of ozone

Diagram showing ozone production and pair particles

Ozone is a by-product of products sold as purifiers that affect oxygen molecules. The basic idea is that safe oxygen molecules are split (often using a high voltage electronic circuit) and free oxygen atoms re-combine into unstable ozone (O3) molecules. These then can sometimes bond with, and affect, airborne contaminants and odor-causing substances. The problem is that ozone isn’t safe at high levels, and these products aren’t as effective as a HEPA purifier.

Ozone is that odd, “fresh” scent you may have smelled outdoors after a lightning storm or from a model railroad set at Christmas time. It’s produced when electricity affects oxygen atoms in the air, which can recombine into molecules with 3 (instead of 2) atoms.

The idea is that the ozone molecules will bond with and trap unwanted elements in the air. The big problem, however, is that at safe levels it’s very ineffective.

At ozone levels where the generator does make a difference, they’re not supposed to be used when humans are nearby as it’s a health hazard.

Image of human respiratory system

Ozone is inhaled when you’re in an enclosed room with products sold as “air purifiers” which are actually ozone generators. The side effects depend upon the amount of ozone you’re exposed to.

Basically, ozone molecules are unstable and when breathed in they can affect your respiratory system. Ozone molecules cause a number of symptoms like irritated and uncomfortable passageways, headaches, pain and coughing, and more. 

The Environmental Protection Agency (EPA) is very clear that ozone is a lung irritant and they don’t recommend introducing ozone-creating products into your home. While ozone can help remove odors from your home, it takes levels that are unsafe for humans to do so.

This means that air purifiers that depend on releasing ozone, called ozone generators, should be avoided.

Some types of electronic air purifiers, like air ionizers, may release small amounts of ozone as a byproduct. In that case, they’re generally safe and can’t make you sick or cause issues, but they’re simply not effective and are not worth the money in my experience.

Which air purifiers are safe and effective?

Levoit LV-H132 Vs Germguardian AC4825 comparison image
Air purifiers that are safe and don’t cause the symptoms of sickness, headaches, or other irritants are those that use a filter and do not produce ozone. Two excellent – and best-selling examples are the Levoit LV-H132 (left) and the GermGuardian AC4825 (right). These types of products work by simply filtering air, and don’t add any unsafe by-products into the air you breather. In fact, they make your air less prone to causing sickness or allergies!

Air purifiers that are filter-based are safe and cannot cause sickness or issues from their use. If anything, they prevent sickness and make the air around you safer and healthier to breathe.

They’re proven to be effective and some major brands have documented effectiveness, based on the Association of Home Appliance Manufacturers (AHAM) lab testing standards.

The most reliable air purifiers are those that use High-Efficiency Particulate Air (HEPA) filters.

These types of air purifiers don’t release any byproducts. Instead, they use a filter made of densely packed thin fibers to remove particulate matter from the air as it moves through when drawn in by fans.

Those thin fibers are woven into a dense mesh and pleated material. This way their surface area is increased. They’re based on an old standard which ensures they can remove 99.97% of particulate matter from the air.

HEPA filters can remove particles as small as an incredibly tiny .3 microns in size. A single micron is 1/1,000,000 in size, meaning that these filters can remove microscopic elements – everything from pet dander to microbes.

And the best part is, unlike air purifiers which make claims that are impossible to test, HEPA filters have specific standards that they need to meet so you can be sure that they actually work.

Air purifier HEPA filter material example close up
A close-up of a HEPA filter. Very dense and made up of tiny fibers, HEPA purifiers often are used with other filter sections like activated carbon and pre-filters to make their products more effective. When used together they’re more effective and can remove sickness-causing vapors, germs, allergens, and much more from the air you breathe.

HEPA filter-based air purifiers (a great example is the GermGuardian AC4825 I reviewed in detail here) work by filtering the air in a room continuously. They use an electric fan or fans to draw in air, move it through the filters, and force out fresh, healthy air.

Therefore there’s no way they can cause sickness. A good product cannot introduce harmful elements into the air you breathe or cause discomfort or any symptoms from use.

There isn’t any way for HEPA purifiers to make you sick, because they aren’t adding anything to the air. They are only taking away irritants that might exacerbate issues for people with asthma or other medical conditions.

Better-quality household HEPA purifiers also contain supplementary filters, like an activated charcoal filter, to trap odors and volatile organic chemicals (VOCs) that cause either unpleasantness or even health issues.

They’re also really helpful for dealing with second-hand smoke effects.

So what air purifier do I need?

The safest option is to use reliable, proven HEPA purifiers that will remove particulate matter from the air without releasing ozone. While shopping, you may also see some air purifiers that say “HEPA-type” instead of “true HEPA.”

This means that they don’t fully meet the HEPA standard of removing 99.97% of particulate matter from the air, but use a filter that is similar in design in some ways. They’re a lower-cost version without the same cleaning efficiency.

I’ve covered HEPA-type vs true HEPA filter differences in this helpful post.

It’s critical to shop wisely.

Poorly manufactured products have a variety of issues:

  • Poor efficiency
  • Some include ozone generators as a 2nd added feature but aren’t helpful
  • Poor odor absorption ability or none at all
  • Missing features you’d like to have
  • Lack of proven technical specifications
  • Poor or low buyer feedback

In summary – can an air purifier make you sick?

Here’s a quick recap of the important things to know:

  • Ozone generator products sold as air purifiers can cause symptoms of sickness and headaches
  • A HEPA purifier does not add anything to the air in your home, so it can’t make you sick
  • HEPA air purifiers actually remove things that make you sick, so they can actually help you stay healthy

Before purchasing an air purifier, it’s worth your time to make sure that the air purifier you are buying is both safe and effective.

For some of the best – and most affordable – choices, check out my recommended models for under $100.

I personally own and use the GermGuardian AC4825, one of the most popular sold today. Here’s my comprehensive and honest AC4825 review.

Your comments are welcome!

  1. Yes I believe she means the Levoit as I also saw that review and am now hesitant to purchase it. I actually emailed the company and this is what they said: “To clarify, all electronics emit a small amount of EMF. However, rest assured that all of the products are completely safe to use in your home. Although the USA does not have any legal standards for EMF levels, Europe does and all of our products have met these requirements.”
    Do you know what about it could be the cause for radiation?

    • Hello, Olivia. I see you’re referring to Jen’s comment.

      I can tell you as an engineer that all electronics (especially older televisions or monitors with a CRT tube) emit electromagnetic fields. Your cell phone, for example, emits MUCH more than any of those do, and dramatically more than an air purifier.

      It’s not a matter of it being an air purifier, per se, as electrical current generates fields. When electrons flow they create electrostatic & electromagnetic fields around the conductor they flow through.

      Purifier & other fans (much like those in your car’s dashboard) are driven by motors with wire windings which rely on magnetic fields to create motion.

      However, most electronics in your home (including air purifiers) use a relatively small amount of power and simply don’t emit any harmful levels. Air purifiers typically use around a max of 55W, and most run at medium or low speeds which is a measly 10-25W or so. A ceiling fan likely generates more, in fact.

      I’m not sure how this became a topic in some cases as it’s not a legitimate source of concern, or I’d be one of the first to mention it. What I am seeing sometimes is there being hype attached to the topic, as if it’s something to be afraid of when in reality it isn’t.

      In fact it’s worth an article in itself as I see this come up periodically. If you want to avoid all EMF (which is virtually impossible) you’ll have to remove all electronic devices & give up your cell phone, too.

      It’s hype without any scientific basis in reality and I dare say reminiscent of the “tin foil hat” crowd stuff.

      I hope this helps clear up the confusion. When people elsewhere promote a false idea and it scares people a bit without a real reason to do so, it’s unfortunate.

      • I had a Reme Halo installed and have had nothing but horrible side effects. They removed it but the smell persists and my respiratory problems are getting worse. Should I have duct work, coil, and plenums replaced to get it totally out of my house?

  2. Hi what do you think of the Eden PURE G7. I purchased it a few years ago. It has an Anion button on it, do you think it is dangerou?

    • Hi Daryl. I looked over the Eden PURE G7. It’s a bit hard to tell exactly how much ozone & ions output it creates (in “PPM”, parts per million).

      I’m having to guess a bit but I think it’s more likely to cause irritation & issues like that after using it a long time. I wouldn’t say it’s dangerous as my first impression is that the output may be lower than some larger units out there.

      You could use it in rooms that aren’t occupied if you like, but my opinion is it’s better to get a HEPA purifier for the rooms you live and breathe in regularly.

  3. I am reading this thread because I wanted to know how the Reme Halo worked, how it create ionized hydro peroxides, and how that cleans and purifies the air. I understand that certain people on this thread have allergies and this particular purifier may have acerbated their problem. Now I’m a little, like Al Pacino said in Scarface, “I’m, how you say it, paranoid.” about the ozone levels. There is a way to control the output on this unit but now I’m a little concerned. I am referencing Linda from March 1, 2019 and Lola K from April, 23, 2019.

    • Hi there, David. Yes, I don’t recommend products like the Reme Halo because they usually end up being another version of an ionizer or ozone generator (or some variation and/or both). The symptoms everyone who’s reached out to me about are nearly always the same, too.

      By-products like ozone can irritate the internal passageways of people regardless of allergies, so in general they’re just not a good idea ever.

      As I mentioned above, you really can’t go wrong just getting a high-quality HEPA type purifier. Thanks for the comment & for dropping by.

  4. Hi! Just wanted to thank you for this information. I just purchased the model Germ Guardian you mentioned and the day after turning it on my grandson caught a cold. I was afraid to could have been from the purifier but your article made me feel much better about my purchase. I’m blaming the cold on his first day at the pool ?

  5. I HAVE A CHURCH AND SCHOOL AND WE ARE TRYING TO DO ALL WE CAN TO IMPROVE THE AIR QUALITY THROUGHOUT OUR BUILDING. I agree with your assessment about HEPA Filters and that is what I want to do in all our Air-handlers as well- However, I am looking for best solution; we have many class rooms and offices and large sanctuary and meeting rooms…
    Manufactures make some amazing claims… HAVE YOU ANY INFORMATION ABOUT ” iWave-R by GPS Nu Calgon”?
    thank you for your informative article and responses
    Pastor Bill

    • Hello Pastor Bill. I don’t recommend those types of products sold as air purifiers. They’re actually ionizers and produce some ozone as a by-product as well, usually. They don’t have much of an impact on air quality unless they produce an extremely high amount of ions. Also they can’t trap and filter the more troublesome contaminants in air like a HEPA filter can.

      They can be helpful for airborne germs and are sometimes used in hospitals or other buildings but they’re not a substitute for actually removing contaminants that most people have problems with like dust, dander, dust mite by-products, and so on.

      Like I mentioned in the article, money is better spent on a HEPA purifier(s). Or add a HEPA filter/filters to the air system if there’s a way to do so.

  6. So why is the fresh smelling air after a lightning storm safe, and why is the air produced by the ionizer air purifiers unsafe?

    What’s the difference? That would mean that the air after a lightning storm is unsafe as well?

    • Hello John. It’s the amount of exposure that makes the difference. When you smell ozone after a storm, or when using an electric train track or toy race car track (2 examples many of us may remember) that’s a very small amount and you’re not constantly inhaling it.

      When using a device that purposely generates high levels of ozone, it’s a different situation. Especially given that you’re in an enclosed room where you’re exposed to it constantly. Very minute levels are ozone are fine and there are standards for the recommended exposure level.

      Ionizers, ozone generators, and other similar products can generate a huge amount far exceeding that.

  7. Grant,

    What about the Tempest, by AirRestore?

    They claim it works differently than anything else, that their technology is unique. Just started trying out these units, and they seem to be improving room odors. I can detect a bit of ozone scent, stronger if a room is left shut up. After reading your article, am concerned.

    How do I figure out if the claims have any validity? And, if it’s safe or not???


    • Hi there, Ann. I had a look at the site and they never actually explain specfically how that works. However, it’s easy to tell it’s some type of ionizer or ozone generator as most gimmics like that almost always are (or some combination or something similar).

      There’s no way to find proof of their claims and to how much it actually produces in the air, as they don’t appear to provide any of that info. It’s probably safe, but still not the best use of your money.

      I wouldn’t spend your money on those – stick with proven HEPA purifiers. Have a good day! :)

  8. Greetings,
    I have read so many things about air purifiers and most answers are that they cannot hurt you.
    We are now using purifiers in the dental office I work in. This is what it does to me. I feel itchy and my skin gets red and hot. I feel I have throat and lung irritation. I feel like I have gotten into fiberglass.
    What should I look for to see if it is an ozone issue?
    Thank you

    • Hello, Lisa. Yes, most should not be able to affect you but like many things, there are always exceptions. If a purifier is generating some type of airborne molecule like ozone, it’s usually (1) an ionizer or ozone generator but called a “purifier” and doesn’t use a traditional filter, or (2) it has a HEPA filter but also some type of ionizer or ozone feature included.

      You can look into the description of it and find out what the manufacturer says. If it’s some kind of ionizer or ozone generator they often use some fancy jargon to make it sound great. A regular purifier won’t normally have that kind of silly marketing.

      NOTE: Some “purifiers” like the Reme Halo are installed in the ventilation or HVAC system. Those do generate a lot of airborne molecules that can really bother you. I had several readers contact me about that and their symptoms.

      I’ve personally had issues due to particles & dust carried by the ventilation ducts in an office building in the past. Some of what you described in addition to heavy coughing due to inhaling airborne irritants.

  9. Are there air purifiers that would neutralize ionized air put off by another type of air purifier? Neighbor in townhome uses an ionizer and it’s seeping through the walls. It’s irritating my eyes, nose, and throat. Any suggestions? Can’t always open the windows.

    • Hi Lizzie. Wow, sorry to hear that. Unfortunately, not that I’m aware of. I can’t help but wonder if they have a device like a Reme Halo in their HVAC system and it’s leaking into your place. It sounds something is putting out quite a bit.

      Several people wrote to me and mention how those caused them problems.

  10. Hi Grant,
    So are Reme Halo’s not good? I just installed one in my home for mold reduction and I am now concerned it will be harmful to my health?

    • Hi there. Ionizers and other things like the Reme Halo won’t help with mold. Mold has to be addressed at its source but a HEPA purifier can help with spores in the air.

      The Reme Halo generates ionized molecules which isn’t the same. Hopefully using it won’t make you uncomfortable but you’ll need a real air purifier if you want to clean your air properly.

  11. What do you think of the new Remi Halo LED, which claims to not release any ozone? Can the new version still cause health issues which impact breathing and coughing?

    • Hi Karen. I still wouldn’t recommend a device like as while it’s listed as not producing any significant ozone, there are other concerns:

      – It’s an ionizer but how much does it produce? Quite possibly a lot and enough to cause discomfort.
      – Not effective like a filter-based purifier at removing dust, allergens, pet dander, etc.
      – You’ll still need an air purifier in the rooms where you stay as the Halo works in the HVAC system; it doesn’t clean the existing air in a room.

      It does appear to offer a UV feature for killing viruses etc in the air but several air purifiers already offer that…and for much less money.

  12. I was considering it for a person who has emphysema. Have you gotten reports from people suffering from this and COPD disorders who have reported increased problems with the Remi Halo LED? Thank you!

    • Hi Karen. No I haven’t heard anything with regards to someone with COPD disorders. Before now (Reme Halo units in general) it’s been people complaining about their eyes bothering them, feeling poor, and aggravated respiratory systems etc. So I would assume the same would be true there as well.

      But it normally depends on how much a unit is creating in the air you breathe and I’m not sure how much the LED model does. The UV feature is harmless but the ionizer (or what other type of by-product it might create) can be a different story.

  13. Thanks for the information. Do you have an opinion about the Plasmawave technology by Winix? It is not supposed to produce ozone. It has a HEPA filter and the Plasmawave feature is optional. I have been reluctant to use it, but I probably would if I felt sure it was not going to cause any problems.) If this has been asked, sorry, I looked but don’t see a post about it.)

    • Hi Jill. The PlasmaWave feature and other brands with a similar device may create a teeny tiny amount as a byproduct of ionization, but not anywhere even close to what a real ozone generator creates. You don’t have anything to worry about.

      I never could really smell or sense anything was “off” at all when using mine.

  14. I purchased a Honeywell Insight HEPA air purifier (500 sq ft) and am wondering if this is as good as I read. I have chronic allergies and have developed adulthood asthma, so I am trying everything that I can to ease my symptoms. Thanks in advance!

    • Hello Lesley. Honeywell makes pretty good ones so if whichever model you bought is correct for the room size you should notice a difference. (Assuming your asthma is related to airborne issues and not something else)


    • Hello Yanira. No, I’m not familiar with those but I had a look. It looks like it’s potentially a good model although no Clean Air Delivery Rate [CADR] specs are provided. I would find out how much replacement filters cost as they potentially could be expensive.

      Best regards.

  15. Hi. I found this researching about Reme Halos. Had my entire system/ductwork replaced because of mold and was told this was what I needed to keep system clean. Before I had it torn out, I had a mold remediation company come in and do an air quality test in the house which they said was good. this is perplexing to me with the volume of mold in the ductwork, but I do have two Air Oasis iAdaptAir® HEPA UV Air Purifiers that I run pretty constantly (never the ionizing cycle). So how do those different from the Reme? So confused. Do I need them with it? Do I need it with them?

    • Hi Suzanne. So basically the Air Oasis units you have are “real” purifiers in that they use a filter to remove nasty things from the air. Stuff like the Reme Halo or ozone generators create a large amount of ions (ozone in the 2nd case) that have an electrostatic charge to supposedly remove air contaminants.

      The issue is that means you’re exposed to it, breathe it in, et. Several people have mentioned how it causes them problems. Also, ion generators etc. are not effective the same way as a HEPA purifier. HEPA purifiers don’t generate anything into the air that you could breathe or feel uncomfortable from. You don’t need the Reme unit.

      Also, the purifiers you have won’t generate a ton of ions so you could use that feature if you like. UV lights and ionizers in purifiers are kind of a “nice to have” add-on and shouldn’t cause discomfort like the other types.

  16. Hi there! Glad to have found this thread. I have mold illness and I am chemically sensitive and had been considering the Reme LED. I definitely think I should avoid this product. I cannot even use charcoal air purifiers like Austin Air due to my sensitivities. I do have an IQ Air that I do well with, but it only filters out mold, bacteria and viruses. Unfortunately for me, I don’t think I can handle any of the purifiers that filter VOCs, etc. With all that being said, what do you think of IQ Air’s whole home AC system or Intellipure’s whole home AC system? Thanks so much!

    • Hello Broooke. The IQAir system looks fine and would be good. For the Intelllipure, I cannot view the specifications without signing up using my email address, so I’ll just say if it’s a filter-based system (unlike things like the REME) it should be fine as well.

  17. I purchased the Levoit P350 on an amazing Amazon Treasure Truck deal this week. I’ve just opened it and set it up and almost immediately I noticed head pressure, my cheeks are flushed, and my eyes itch. It specifically states in the description that it doesn’t use ions, which are harmful to people and pets, and uses H13 true HEPA filtration. Am I just one of those random people that has adverse reactions to purified air, even when it’s not from an ozone producing machine?

    • Hi Susan. It may be “outgassing” as it’s brand new. Sometimes new filters etc. have an odor until they run and it has a chance to clear out.

      I would let it air out in the fresh air (not running) or let it run in another room with the door shut for a number of hours. This normally shouldn’t be an issue.

  18. Hello! I’m looking into the Reme LED for my home, since it’s apparently been certified as ozone- and mercury-free. I am apprehensive about the constant inhalation of its byproducts, though, no matter how much I’ve read that they’re safe. Have you heard much about the LED model and its relative likeliness to cause ill effects? My goal here is to remove something like 40 years’ worth of scented candle fragrances from the house. I had been looking into a whole-house three-stage filter, but my HVAC guy suggested this. Thanks!

    • Hello Andy. So after reading about the LED model here’s what I think. I think you simply won’t really have any way to know if you’ll have ill effects or not until trying it. With the Halo model, I did hear from several people who complained of discomfort (bothered their eyes, throat/lungs, and some other symptoms).

      The LED is supposed producing less output than the Halo, but who knows how much specifically? My personal opinion would be to avoid that type of device if you’re concerned about suffering effects from it. If you have a build-up of odors from scented candles my first thought is that there is residue on your interior & carpet that would need to be cleaned, similar to how indoor smokers have yellow walls and odors/particulates trapped on surfaces around them.


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