Air Purifier vs Ionizer – What’s the Difference?

With the coronavirus delta wave in full swing, maintaining good indoor air quality has become more important than ever. Air purifiers and ionizers both bring very different approaches to cleaning the indoor air and are quite effective at it. 

Different types of air purifiers feature a set of filters and offer various health benefits. Air ionizers also bring down the air particle concentration and bring the benefit of having zero maintenance costs. But the use of advanced technology to tackle unwanted particles adds a non-financial additional cost. 

If you’re looking to buy an air-cleaning device and are confused between an air purifier vs ionizer. This guide will help you understand both the devices, how they function, and what will be the best choice for your indoor space.

What is an Ionizer?

Ionizers are devices that improve air quality by producing negatively charged ions that latch onto the airborne particulate matter in a room. This makes the contaminants too heavy to stay airborne. These heavy particles then stick to the nearby walls, floors, countertops, draperies, etc. This can result in an increase in surface dust levels in the first few weeks of usage, particularly if the ionizers lack collection plates.

How do air ionizers work?

Ionizers have special plates inside them that produce electrical charges that are sent out of the machine with the air. These charges cling to the small particles in the air either making them too heavy to stay airborne or convert them into a different substance altogether. 

The nifty technology is efficient at handling small-sized particles but loses its efficiency as the particle size increases. Some ionizers have an electrostatic collection plate that attracts the contaminants back into the machine.

The only problem with negative ion charges is accidental ozone generation. Ozone is a lung irritant and can adversely affect human health. Static electricity and unsafe levels of ozone can lead to respiratory issues. In addition, because the ionizers cause particles to clump together and settle down, mold spores can settle onto surfaces and that can actually speed up their spread.

What is an Air Purifier?

An air purifier is any device that filters dangerous particles in indoor air by using a mix of air filters. Air purifiers can trap particles as little as 0.3 microns in size, these include dust particles, dust mites, animal dander, mold spores, etc. A standard air purifier features 2-stage filtration, with advanced ones bringing in at least a 3-stage filtration system. 

Advanced air purifiers can feature as high as 6-stage filtration with the ability to neutralize VOCs, harmful effects of gases and can even add a scent to the purified air. The Asthma and Allergy Foundation of America suggests using an air purifier to improve indoor air quality and for alleviating asthma symptoms. 

Air purifiers use different technologies to filter and clean the indoor air, these can range from the use of mechanical high-efficiency filters to electrostatic charge or negative ion filtration. Depending on the type of air purifier you opt for, the advantages can vary.

How do air purifiers work?

Air purifiers feature a series of filters and depending on the number of stages of filtration, the air is passed through:


The pre-filter is made of either synthetic non-woven material or a cotton blend that is usually washable. It filters large particles from the air like pet dander, hair, pet fur, and dust before the air is passed onto more specialized filters. Because these can usually be washed, pre-filters can last a long time.

HEPA Filter (High-Efficiency Particulate Air Filter)

A High-Efficiency Particulate Air Filter can filter out 99.97% of airborne particles, even microscopic particles with tiny size of 0.3 microns (µm). Medical-grade HEPA filters can filter 0.3-1 micron size particles with an efficiency of 99.97%. True HEPA filters can filter even further with improved efficiency of 99.99%

Carbon/Activated Carbon Filter

An activated carbon filter is particularly efficient at neutralizing organic compounds and can help alleviate allergy symptoms by taking care of cooking odors and chemical odors around the house.  Different manufacturers use variations of carbon filters that assist the other filters in the air cleaning process.

Carbon filters are great for odors but come with their own drawbacks. Carbon filters can off-gas, i.e. emit absorbed gas back into the indoor air.

Additional Stages

Air purifiers are evolving with time and some manufacturers are adding innovative features like UV-C chambers and ionizers. These extra filtration stages allow air purifiers to work like air scrubbers and ionizers while also efficiently removing the contaminants.

Air Purifier vs Ionizer

So, What is the difference between air purifiers and ionizers?

Air purifiers filter the indoor air using series of mechanical filters and can trap pollutants effectively. Air Purifiers are effective against dust, smoke, smell mold, and VOCs. On the other hand, ionizers use negative ions to make the air pollutants heavy. It can cause harmful particles to settle down and lack any physical filters.

When comparing air cleaning performance, air purifiers come out on top as some air purifiers have specialized models that incorporate an ionizer.  Ionic air purifiers bring the best of both worlds and add an extra stage of filtration to air purifiers.

CharacteristicAir PurifierIonizer
Removes Dust, Smoke
Removes Odors, VOCs
Helps treat Mold
Leaves behind residue
Power Consumption10-100 Watts5-50 Watts
Operation costModerateLow
Annual CostsModerateZero

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Air Ionizer vs Air Purifier – Takeaways

Air purifiers and ionizers both clean the air. Ionizers are particularly efficient against small particles whereas an air purifier can handle particles of all sizes. While air purifiers use mechanical filtration, ionizers use negative ions to make the air pollutants too heavy to stay airborne. However, if you have severe air quality issues and have a mold infestation, then an air purifier will be a better option as it can eliminate airborne pollutants with an efficiency of 99.99%.

Depending on the level of contaminants in your indoor air, you might need to use both an air purifier as well as an ionizer. An ionizer can assist a purifier in removing allergens and other contaminants. Some manufacturers offer an air purifier that is equipped with an ionizer.

Ionic air purifiers have physical filters just like HEPA air purifiers. This helps in removing the additional dust produced by the ionizer. Before making the final decision, it is important to understand that air purifier replacement filters can be costly to replace, whereas ionizers don’t require any such expense.