Air Purifier Vs Ionizer – Which Is The Safer Choice?

Josh Mitchell

Written By

Josh Mitchell

Expert Reviewed By

Holly Curell

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Key Takeaways

  • Air purifiers and ionizers are both devices that are used to remove harmful particles and pathogens from the air.
  • Air purifiers use HEPA filters along with other technologies like activated carbon to remove most contaminants from the air. Ionizers use negatively charged ions to clean and sterilize the air.
  • Ionizers are generally considered more dangerous for homeowners as they may produce ozone as a byproduct which poses health risks.

Both air purifiers and ionizers promise to remove harmful particles and even airborne viruses from the air. Since both machines promise to do the same thing, I’ve encountered countless people over the years who don’t know which to buy.

I want everyone to breathe clean air, but I don’t want them to risk their health in doing so.

So to help give you clean air without adverse health effects, let’s discuss whether an air purifier or an ionizer will provide the safest and most effective solution for improving the air quality in your home.

Air Purifiers Vs Ionizers – Key Differences Explained

Operating And Filtering Particles

HEPA air purifiers are common in residential and industrial settings, where they filter out fine particles. HEPA filters use a combination of interception, diffusion, and electrostatic attraction to trap and filter particles as small as 0.3 microns, making them highly effective at removing allergens, pollutants, and other airborne particles from indoor air.

Ionizers filter particles from the air by attaching negatively charged ions to airborne particles, making them negatively charged. This causes the particles to be attracted to positively charged surfaces, removing them from the air.

Safety For Homeowners

HEPA air filters remove most harmful particulates, but these air purifiers cannot remove gaseous compounds like volatile organic compounds (VOCs) or odors. To address these, some air purifiers may use additional technologies such as activated carbon filters. HEPA purifiers are generally safe for homeowners.

Ionizer air purifiers also cannot remove gas or odors. Some ionizers can even produce ozone (O3) as a byproduct of their operation. While ozone can be helpful for air purification, it can be toxic in high concentrations, particularly when inhaled over extended periods of time.

Contaminants Targeted

Both HEPA air filters and ionizing air purifiers are good at removing more significant air pollutants such as dust, pet dander, or allergens. HEPA air purifiers, however, can remove smaller airborne contaminants than ionizers. Neither HEPA systems nor ionizers can remove gaseous products from the atmosphere. Also, air ionizers may not trap bacteria and viruses because they are too small.

Appliance Size & Design

HEPA filters come in a wide variety of air purifying units and may be upright, horizontal, or tabletop humidifiers. Similarly, ionizing air purifiers can come in several shapes and styles. No matter the style, you should be able to operate the devices using an input pad to set cycles and intensity.

Coverage Area In The Home

The coverage area depends on the air purifier that you get. In general, a decent mid-grade air purifier will cover anywhere between 500-1,000 sq. feet. The most powerful industrial-grade air filters will cover up to 3,000 sq. feet or more.

Cleaning & Maintenance

All filters and air purifiers need to be cleaned and maintained. Filters get dirty over time and need to be replaced, and the electric plate ionizers need to have the plate screens cleaned of dirt and debris. A good HEPA filter can last between 2-3 years, depending on how much filtering it’s doing.

Purchase Cost

Depending on the specific brand, model, and features, HEPA filter systems typically cost more than ionizers. While some air ionizer models can be purchased for around $50, HEPA filter models are also available at a similar price point. While some HEPA filter purifiers may cost significantly more than ionizing air purifiers, this is not always the case.

It’s worth noting that replacing HEPA filters can add to the overall expense of using a HEPA filter purifier over time.

How Do Common Household Air Purifiers Work?

The acronym HEPA stands for high-efficiency particulate air and is a special kind of air filter that is extremely effective at removing particulates in the air. HEPA systems trap particles and can remove airborne particles as small as 0.3 microns in diameter for a theoretical removal rate of 99.97%. Some HEPA systems also use an activated carbon filter.

  • Diffusion:
    A HEPA filter will use the diffusion of dust particles into a tightly packed fiber matrix to capture larger particles that could cause respiratory irritation.
  • Interception:
    A HEPA air purifier will also work by directly intercepting particles as they travel through the air, capturing them in fiber layers.
  • Impaction:
    Large particles cannot avoid fibers as they curve through the airstream. Impaction filters are most effective with large air volumes.

Pros & Cons Of HEPA Air Purifiers

  • Removes 99.97% of airborne particles
  • Highly efficient design
  • Long-lasting
  • Highly effective for particles
  • Maintains humidity
  • Relatively expensive
  • Does not remove VOCs
  • Can inculcate mold spores

How Do Ionizers Work To Clean The Air?

Air ionizers work a bit differently than HEPA filters. Ionizers are air purification systems that use electrical charges to remove particulates from the air. They are different from regular air purifiers because Ionizer air purifiers release negative ions into the air.

The electrical charge from these negative ions attracts positively charged ions, which carry dust and bacteria. THe particles batch together and fall from the air. Air ionizers are good for removing larger particles, but might have trouble with very small particles.

  • Particulate pollutants
    Ionizers use electrical charges to attract other large particles that might get in the air. The negative ions attract positively charged ions to remove things like dust and other indoor air pollutants.
  • Gaseous pollutants
    Ionizer air purifiers do not work on gaseous pollutants, including VOCs or odors. Ionizers may also produce ozone which can interact with gaseous products. The ozone produced can be harmful in large amounts.

Pros & Cons Of Ionizers (Ozone Generators)

  • Remove larger airborne particles
  • Can remove bacteria
  • Low energy
  • Removes dust and allergens
  • Electric plates are highly effective
  • Can create ozone, which is toxic in high concentrations
  • Electric plates can get dirty

Common Questions About Air Cleaners

Do air purifiers or ionizers clean cigarette smoke better?

Both HEPA and air ionizer air purifiers purify smoke very well. However, a HEPA air purifier will probably do it better because it can capture all tar particulates.

Do air purifiers or ionizers clean mold better?

HEPA filters can remove mold spores, but they may not kill them outright. If humidity is high, mold spores can grow in a HEPA air purifier if they aren’t clean. Ionic air purifiers, on the other hand, will not kill mold.

Can you clean and reuse HEPA filters?

Generally no. While you probably could clean a HEPA filter and reuse it in your air purifier, it would be difficult to do, and you would probably break the filter in the process. It’s best to buy a new one when you need it.

How often do you change HEPA filters?

A good HEPA filter should last about 2-3 years, depending on where it is being used. It will last longer in places where there is less general air pollution.


I know firsthand how important it is to maintain clean air for a healthy indoor environment. I also know that while both HEPA air filters and air ionizers are viable options, if safety is your main concern, a HEPA filter is the way to go.

When working with clients, I discuss their concerns and preferences to find the most effective and affordable option. If safety is a concern for them, I recommend combining a HEPA filter with an activated carbon filter to remove a wide range of air pollutants.

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Josh Mitchell


Josh Mitchell
My name is Josh and I am obsessed with home appliances. From portable AC units to heaters and air purifiers, I enjoy testing, learning and using these devices to improve the air quality inside my family home.

My Favorite Home Appliance?

Midea U Shaped Window Air Conditioner

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