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!

    • Hello Steven! I had a look at the Eureka InstantClear and here are my thoughts as I haven’t had the opportunity to try it personally.

      – Good CADR ratings and it’s lab tested, which demonstrates proven performance. This is a great thing.
      – Nice medium room square feet coverage for the price.
      – Looks to have a nice build quality, controls, and ease of use.

      It reminds me a lot of the GermGuardian design. From what I see, it looks like it’s potentially a good option worth trying.

      Bear in mind I think the replacement filters may run a bit more than competitors which are more popular (Honeywell, GermGuardian) as the replacement options are more limited.

      I hope this helps!

  1. Are you familiar with the reme Halo? I recently purchased it in addition to the expensive new heating and air system I had installed. It creates an advanced oxidation plasma of ionized hydroperoxides superoxide ions and hydroxide ions. The first thing that I noticed was the strange outside air smell in the house that I didn’t necessarily like, but had to get used to. I also called them back because my eyes were burning so badly. I asked them to turn down the ionizer which they did. I am now thinking of asking them to take it out completely for two reasons. When the ionizer is turned down, I’m sure it’s not doing much. I also don’t know what else to attribute my constant eye irritation to at this point. My eyes are now red and swollen all the time and even peeling on the eyelids. The eye doctor was not sure what was causing it but tried a full round of antibiotic ointment which had no effect. Am I crazy or can this truly be a result of the air purification system?

    • Hi Linda. I wasn’t familiar with the Reme Halo device, so I did some reading before replying. I’m sorry to hear you had to suffer what sounds like some very uncomfortable side effects.

      It’s really hard to say exactly what it produces (given how much jargon they use, and the lack of details about safe ozone or ion levels). It does seem to be a type of ozone device, ion device, or both, that I mentioned in my post that can cause these kinds of problems.

      I believe that yes, it could be a result of that Reme Halo introducing those elements into the air. Honestly, I think you should disconnect it yourself or get them to disconnect it for a while and see how you feel.

      Then you should have a pretty sure idea if it’s that or not (I think it is). If you need safe clean air, I definitely recommend staying away from things like that and using filter-based purifiers that can’t give you those kinds of problems.

      I hope this helps, and I certainly hope you feel better soon!

    • I just purchased a Reme Halo. When I asked the guy flat out, “does it produce ozone?”, he conceded and said, “yes”. I for whatever reason assumed the ozone was a byproduct of the system and thought to myself, at least the ozone is in my garage and not in our home. My thought was that we always have our garage open and when closed we are in and out quickly. I thought incorrectly, it was not going to be in my home.

      I immediately felt something off in the air. I can’t explain it but it was just clearly different but clearly uncomfortable. I finally sat down and (more) carefully read through the material. I then realized the ozone is in our home and most importantly all the certifications I read about were for businesses; the food industry. So while I glanced at studies, and awards and certifications I didn’t make the connection that nothing directly tied to the residential units.

      Clearly I’m no genius and don’t know the science involved, but I’m convinced the humidity in my home increased as a result. High humidity can be really uncomfortable and for the extremely sensitive like me, it can be difficult to breathe in. I get tightness in my chest if my fan isn’t on during a hot shower! I was running over 50% with the Reme Halo but more importantly the difference between the outside RH and inside was minimal and at times greater in the home. The house never felt cool despite the low setting and the air felt “thick”.

      Like you I also had burning eyes. My nose and eyes were constantly burning and it was immediate. I’d come home from work and within minutes I would feel the burn. Sleeping was difficult as we added a second vent in our room at the same time we did the install. Conceivably we had more ozone in the room because of the added vent and the small back office I frequently slept in because it was the “clean” room, I couldn’t sleep in after the Reme Halo install. One night I went into my garage to sleep on the sofa because it was better than being inside. I know it is crazy but my dogs eyes were red and irritated. He was draining as if he had pink eye.

      My husband called and they lowered the output (the “stick” can be pulled outward or pushed inward to modify the output). The first thing I noticed is that my house wasn’t as humid. As I’m typing, my thermostat shows a 10% difference between outside and inside RH and it’s been below 50% ever since.

      Even though I feel better (and the dog too), I’m having it uninstalled next week. I’m out the cost of labor but I’m concerned that even though my family doesn’t react to the ozone the way I do, it is having an affect on them that they simply don’t notice, My body is sounding the alarm theirs isn’t but it doesn’t mean it isn’t doing anything to them.

      Not being able to control the levels in individual rooms regardless of what the company says it puts out as a whole is a problem for me. The unit might pump out X ppm which is safe when measured against the size of a home, but the difference in how I felt when walking in or out of my home was discernible enough. The difference I felt in various room was even greater and that, well, I found alarming. There was no “thermostat” in the rooms to ensure even distribution.

      In the end, the unit was installed to help with my allergies, not make me feel worse. Regardless of ozone, ionizers, etc. the unit simply didn’t work.

      • I have recently installed two Reme Halo Led’s. It’s been about two weeks sine the install. I think the devices might be causing the two occupants of my home to experience joint pains. Has anyone experience this?

          • We have a Reme Halo LED – and since that time have noticed an increase smell in our basement – although I am the only one who can smell it. We are unplugging it for a while and seeing if that fixes the problem – will let you know. Hoping that is the case as would love to have a smell free house again!

  2. Hi everyone. For those that have had issues with air purifiers, I suggest looking into the MERV rating of whatever filter you are using…the higher the rating, the more particulate matter is trapped in that filter…if it’s not fine enough to trap whatever allergen you’re sensitive to, it WILL make you worse, because it’ll just blow stuff around.

    • Hi AM, I appreciate your comment. However, MERV doesn’t apply to home air purifiers, as all quality filter-based products use a true HEPA filter that meets the minimum filter performance standard. (Aside from “HEPA type” filters, which are a bit less strict).

      Looking for MERV filters a good tip for HVAC filters, however, as I know not many people may be aware of that. Thanks.

  3. Hello, I would like to know if it’s true what one of the comments on Amazon that the Levio gives off a lot of radiation. Is that true? I’m concerned as I own one. Thank your help.

    • Hello, Jen. I’m not sure which comments you’re referring to, or if you meant “Levoit” instead of “Levio.” If you can clarify where I can read the comments I’d be happy to look it over.

      But basically, an air purifier cannot give off radiation. There’s no radioactive materials in them. Did you perhaps mean ions, ozone, or something similar?

      Basically, certain types of products sold as purifiers (ionizers/ozone generators etc.) can do so in that case. The Levoit brand does not use that, however.

  4. I have a question regarding the ill effects of air purifiers on human health. Like we know, its harmful for us to inhale the polluted air, and air purifiers are actually useful in cleaning this air and help us breathe clear and fresh air, thats one advantage.

    But at the same time, how does it affect human health in a bad way? Like at our homes, we are able to breathe clean air because of the air purifiers but when we go out we are suddenly exposed to all the pollutants and particulate matter that might make us sick.

    So isnt it possible that air purifiers are actually reducing our resistance towards the poor air and the ability to fight infections or diseases because we are actually adapting ourselves or being habituated with the clean air that is offered by air purifiers?

    • Hi there, Max. No, air purifiers don’t have a negative effect that way.

      Any ability to fight sicknesses is due to your immune system. We’re exposed to a huge range of germs and sources of sicknesses from birth to adulthood that aren’t even airborne at all. (For example, sick people, contaminated objects or surfaces, food & liquids, etc.)

      One reason air purifiers are so beneficial is that unlike the outdoors, homes and other enclosed rooms build up one or more air quality problems that you’re constantly exposed to. That’s because unlike the outdoors, there’s no circulation of clean or fresh air. Also, people, pets, materials, and HVAC systems and so forth continue to add to the problem.

      They won’t have an impact on your immune system at all and can only improve your health.

  5. 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.

  6. 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.

  7. 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.

  8. 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 ?

  9. 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.

  10. 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.

  11. 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! :)


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