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Do ionizer air purifiers work?

Air ionizers improve air cleaning performance but they also create certain by-products that could harm your health
Updated on November 19, 2023
Written by
Gisele Navarro
As the Managing Editor of HouseFresh, Gisele runs the day-to-day operations of our editorial team. She supports Danny and Ted with product tests, and works with the writers and producers to continually improve our content. She is also the human behind our X (formerly Twitter).

Ionizers can improve the ability of a mechanical air purifier to remove particles and odors from the air, but they produce harmful levels of VOCs and ozone — they are simply not worth the risk.

In contrast, purely mechanical air purifiers that use HEPA and activated carbon filtration have zero risk, so they are much better. 

You should carefully consider whether or not a device that creates more air pollutants is a wise choice.

If you don’t have time to read this full article, here’s a summary of what we will cover:

  • Ionizers can slightly improve the efficiency of mechanical air filtration of HEPA and activated carbon filters, boosting the ability of the unit to remove particulate matter and odors from your environment.
  • Unfortunately, they do this by generating and releasing negative ions into the air, which can produce a harmful gas called ozone and also increase small particulate matter (PM2.5) levels along the way.

In this article, we’ll dig deeper into what an air ionizer is, its potential harm and its limitations. 

Ready to learn more? Let’s get to it!

What does an air ionizer do?

For this one, you’ll have to think back to your high school chemistry lessons.

Ions are so minuscule that they’re invisible to the human eye. Nevertheless, they’re all around us, floating in the air.

Remember particles and molecules? They’re all made up of ions, which can have either positive (cation) or negative (anion) charges. Negative ions (anions) become negative when they gain an electron, whereas positive ions (cations) become positive when they lose an electron. 

Unlike an air purifier, which works by filtering through a series of finer and finer filters, an air ionizer generates negative ions, which are then released into the surrounding air. 

These are then attracted to positive particles in your atmosphere, such as cigarette smoke. This creates an electric charge, which causes the particles to stick together.

Once stuck together, they land on surfaces around you. This can include your ceiling and walls, floors and tabletops and furnishings, such as curtains, rugs and carpets.

These clumped-together particles can then be removed and cleaned away. Sometimes, the ionizer will have metal plates built-in, which collect the particles for you. You will, however, need to wipe these down from time to time.

Are you still with me?

Now that you understand how ionizers work, let’s go over some research about their air cleaning efficiency and the effects they can have on our health.

The pros and cons of air ionizers

While ionizers can be beneficial, they can’t completely clean up your environment. 

Let’s get into the pros and cons:

Air ionizer pros

Ionizers can remove certain-sized particles from your environment. The result is that odors may be removed, which can help make your air feel fresh.
A 2018 study found that negative ions could efficiently remove particulate matter, even including ultrafine particulate matter. They were also able to kill mold and fungi.
A 2013 study also found that exposure to negative ions in high-density could contribute to a lower depression score, decrease stress and positively affect sleep and comfort levels. 
Another study conducted in 2021 also found that positive and negative ions could significantly create an antibacterial atmosphere against bacteria. The study concluded that air ionizers would be handy for tackling airborne bacteria and infections.

Air ionizer cons

The EPA notes that ionizers are ineffective at removing gasses (such as VOCs), odors, pollen and house dust from your environment. They can even create VOCs as a by-product
Ozone is also generated as a by-product of ionizers, a known lung irritant harmful to your health. There can be all sorts of harmful side effects from inhaling ozone, which in the short term can include:

– Irritation of the throat
– Chest pains
– Coughing and shortness of breath
– Breathing difficulties
In the long term, you could also be looking at more serious lung conditions. A 2008 study found that ionizers were generally not strong enough to affect particulate levels unless they were particularly strong.
Another 2008 study also found that in addition to ozone, formaldehyde and ultrafine particulate matter were released into the atmosphere by ionizers. 

HouseFresh doesn’t recommend air ionizers

“Research shows that negative ions could enhance the ability of an air purifier to remove particulate matter and odors, including mold, fungi and even bacteria.

However, ionizers can generate ozone, VOCs and nitric oxide, leading to many health problems. That is why we do not recommend air purifiers that use this technology to anybody with respiratory issues or serious illness.

In our opinion, ionizers are not worth any risk when HEPA and activated charcoal don’t create chemical byproducts and work exceptionally well at removing harmful particles and gases from the air.

That being said, there are many good air purifiers on the market with ionizer functions that can be turned on and off for those who want to supercharge the air-cleaning performance of their units in specific situations but who prefer not to have an ionizer running in the background all the time.”
— Danny Ashton, HouseFresh Founder & Senior Writer


About the author

Gisele Navarro

As the Managing Editor of HouseFresh, Gisele runs the day-to-day operations of our editorial team. She supports Danny and Ted with product tests, and works with the writers and producers to continually improve our content. She is also the human behind our X (formerly Twitter).