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

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. These types of products work by simply filtering air, and don’t add any unsafe by-products into the air you breathe. 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 headaches 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 that 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 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 quite the same cleaning efficiency although they’re ok for many situations aside from cigarette smoke, viruses or microbes, and other more difficult air quality problems.

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
Grant Williams

About the author

Grant is a professional engineer by trade and has experience with both maintenance and do-it-yourself home projects. He enjoys sharing his expertise & ideas with others to help them improve their comfort and quality of life. Read more »

Your comments are welcome!

  1. Hi there, this is great info! I have the Germ Guardian model AC4300 Series, it has a UV-C light which is optional to turn on or off, in addition to a true HEPA filter. The pamphlet that came with it indicates the 8 hour TWA ozone for the product is 0.001ppmv when tested in a 30 sq. meter chamber. In chatting with my husband, he believes the unit only emits ozone when the UV-C light is on, and with it off, the unit should simply be running as a fan with a HEPA filter. Do you think this sounds correct? Thanks so much!

    Reply
    • Hi Mary! Sorry for the delay in replying. think I didn’t get a notification about your comment somehow. My apologies. :) I’m glad you found my info helpful.

      Yes, your husband’s right and what you and he both suspect is 100% correct: there’s only a (very tiny) amount of ozone produced and only when the UV-C bulb feature is on.

      You can leave it on all you want because it’s such a minuscule amount it’s not even close to being a problem. That also goes for most brand name purifiers with similar features or a plasma/ionizer feature.

      If you’re ever around a real ozone generator or ionizer, you’ll know right away. Might even start coughing as they put out so much it becomes bothersome and can irritate your throat and eyes. You can smell the heavy ozone as it’s a very unique smell. Ionizers can also have a distinctive by-product you can sense.

      Best regards!

      Reply

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