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What is an ionizer?

Updated on November 15, 2023
Written by
James Booth
James has over ten years experience as a content producer and editor. He focuses on writing articles that are compelling, clear and, more importantly, helpful to the readers. He honed his research and copywriting skills working as part of NeoMam Studios, the parent company of HouseFresh.

Ionizers (also known as ionic air purifiers or ion generators) produce electrically charged particles that attract and attach to mid-sized air contaminants such as some bacteria, dust, and mold.

However, while they can remove smoke and odors, they cannot remove mold spores, may have limited effect on viruses and emit harmful toxins during the process. This includes VOCs such as formaldehyde and ozone.

Exercise caution when considering installing an ionizer in your home; do your research carefully and thoroughly.

With us spending a lot more time indoors these days, you may wonder what you can do to clean the air around you. While air purifiers are obvious, you may have also heard about air ionizers. However, while air purifiers are pretty much what it says on the box, what exactly is an air ionizer, and what does it do?

Here is a handy graphic for those of you who are visual learners:

Now that you know more about the overall approach, let’s back up a little to talk about what air ions are. Time for a mini science lesson.

In the air around us are invisible molecules made of ions. Ions contain electrical charges, which are either positive (cation) or negative (anion) charges. When anions gain an electron, they become negative charges, but when cations lose an electron, they become positive charges.

So, the idea behind air ionizers is that they produce and release negative ions into the atmosphere, which are then attracted to and able to attach to positive particles in the air around you. This includes things like tobacco smoke or odors.

When negative and positive ions are attracted to one another, this creates an electrical charge, and the particles become stuck.

The stuck particles are then too weighty to remain in the atmosphere, so they fall onto positively charged surfaces around your home and stay there. This can include your:

  • Ceilings and walls
  • Floors and tabletops
  • Curtains, carpets and rugs

The particles can then be cleaned from these surfaces, removing them from your environment.

Some models of ionizer devices have metal plates built into them which also collect these particles. These can then be wiped away from the plates.

As you can see, this is quite different from what air purifiers do. When used together, they can be quite effective and some air purifiers double up and include ionizer functions.

Are ionizers good?

While ionizers can be effective at removing certain things from your environment, they are nowhere near as effective as air purifiers and, in addition, can introduce many unwanted toxins into your home.

📝 A 2021 study co-authored by Illinois Tech, Portland State University, and Colorado State University researchers found that while ionizers could decrease certain VOCs from your environment, they, unfortunately, led to an increase in others. These harmful VOCs were most commonly found in paint, pesticides and aerosols. 

📝 This study was backed up by a previous 2008 study by researchers from The University of Texas, which found that the potential benefits of ionizers were overshadowed by the harmful pollutants and ultrafine particles created when running the device. These included ozone and formaldehyde, which increased significantly in the atmosphere.

📝 Another study from 2021 also found that while ionizers could be helpful in effectively removing particulate matter from your environment, they could also potentially harm the health of some, especially asthma sufferers. The conclusion of this article stressed the need for further scientific study to be conducted, investigating what — if any — were the clinical benefits of such devices before bringing them into our environments.

📝 However, on the flip side of that, a 2017 study conducted by Australian researchers found that ionizers could be quite effective at removing particulate matter from large rooms with a footprint of 25 m3 or more. This was especially true compared to the particulate matter removal results of a high-flow HEPA filter air purifier in the same space. It’s important to note that the air purifier was much more successful in smaller rooms. In addition, the effectiveness of the air purifier and ionizer decreased as the room size grew.

📝 Another 2018 study also found that negative ions could efficiently remove ultrafine particulate matter. This study also investigated the claims that negative ions could kill certain microorganisms and regulate mood but concluded that there wasn’t enough evidence to back these up. They did, however, investigate the potential behind plant-based ionizers and found that this could be highly effective in the future (though again, more study was needed).

Understanding the disadvantages of using an ionizer

As we’ve already discussed, while ionizers can effectively remove certain particulate matter from your environment, there are many more disadvantages.

1. Ionizers are not effective for removing larger particulate matter. This includes 💨 dust, 🌼 pollen and 🐶 pet dander. All these are known to be triggers for those with allergies or asthma.

2. Ionizers can cause asthmatics to suffer from increased symptoms, making them especially dangerous for people with asthma.

3. Ionizers cannot remove gasses and odors (including VOCs) and can even increase the presence of certain VOCs when running. VOCs can be extremely harmful to your health. In addition to various symptoms, including eye irritation, nose and throat, they have even been known to cause cancer.

4. Due to how ionizer devices work, they emit ozone as a side effect. While ozone has been shown to potentially help remove viruses from your environment (particularly from water), it has many detrimental qualities that could negatively affect your health.

Some of the more short-term effects may include:
❌ Irritation of the throat
❌ Pain in the chest
​​​​❌ Coughing
​​​​❌ Shortness of breath and difficulty breathing

However, in the long-term, inhalation of ozone could lead to:
❌ Decreased lung function and inflammation of lung tissue
❌ Increased asthma symptoms and a higher probability of respiratory infections

The potential risks far outweigh whatever good could come from running ionizers in your home — especially if you have members of your household who are higher-risk individuals.

Danny’s Verdict: HouseFresh Doesn’t Recommend

“Ionziers have been proven to generate a lot of Ozone and Nitric Oxide, which can cause a ton of health problems.

We do not recommend air purifiers that use this technology.

– Danny Ashton, Senior Writer @ HouseFresh

Final thoughts

Ionizers are an alternative device to air purifiers that work by emitting negative ions into your environment. This allows them to become attracted to certain positive ions, including various pollutants, causing them to fall from the air onto surfaces around your home.

While they can be effective, especially in water filtration systems and larger rooms exceeding 25m3, there are many more negative health considerations with ionizer devices. 

This is because they are ineffective at removing larger particles and also emit VOCs and ozone as a side effect. If you’re considering an ionizer in your home, conduct thorough research beforehand and carefully weigh the pros and cons. 

While it’s tempting to buy into the rhetoric that ionizer device distributors are pushing, the science tells us that this is still a relatively low-researched field regarding the potential positive outcomes.


About the author

James Booth

James has over ten years experience as a content producer and editor. He focuses on writing articles that are compelling, clear and, more importantly, helpful to the readers. He honed his research and copywriting skills working as part of NeoMam Studios, the parent company of HouseFresh.