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What Does An Air Purifier Do?

Derek Hales

Written By: Derek Hales

Published on:

You’ve likely seen, heard, or been told that you may benefit from an air purifier. But what exactly does an air purifier do? Get the 411 of what you really need to know about air purifiers right here.

Table of Contents

What is an air purifier?

An air purifier is an electroncally powered device that pulls air in from the surrounding air space, forces it through an series of filters before expelling the clean air through the air grille at the top.

Best Air Purifier
Popular air purifier models we’ve tested

While every air purifier is different, the goal is the same. Clean the air in the room by removing floating particulates, gasses, odors, and other irritants.

Types of Air Purifiers

The four most popular types of air purifiers include the following filtration styles:

  1. HEPA
  2. Carbon
  3. Ionizer
  4. PECO

What’s the difference between these types?

Here are some of the most popular models of the different types of air purifiers that we’ve tested to date. Click on the links below to read our full review of each model.

It’s important to note that many air purifiers utilize multiple filter layers to achieve better overall filtration.

Winix 5500-2 air purifier
Winix 5500-2 air purifier

For example, the Winix 5500-2 uses HEPA, carbon, pre-filter, and an ionizer. We just listed it under the best carbon because it does such an amazing job at removing smells.

#1. HEPA Filters

HEPA filtration systems use a filter made of thin folded paper that captures ultra fine particulates.

360° HEPA filter on the Levoit Core 300 air purifier
Levoit Core 300 HEPA filter

These particulates, which are caught stay lodged in the filter and only clean air passes through to be redistributed into the space.

True HEPA filters stop particles from traveling into clean air
How HEPA filters trap particulates

Not all HEPA filters are created equally. Higher performance HEPA filters can remove fine particulates from the air. See our deep dive guide on HEPA filtrations here for more info.

#2. Carbon Filters

A Carbon filtration system use activated carbon to absorb odors and unwanted smells from the air.

Carbon filter on the Airdog X3
Carbon filter for the Airdog X3

Filters with carbon in them can capture these odors and diffuse them in the carbon itself.

Dyson BP01 HEPA and carbon filters
Carbon filters absorb odors and VOCs

Oftentimes, carbon filtration is paired with a HEPA system and both filter techniques are used together.

#3. Ionic Filters

Ionizer systems use negative-charged ions to attract to positively charged airborne particles in your room and sink them to the floor, where they can later be vacuumed up.

how air ionizers work

Getting these particles out of the air is the first step in preventing airborne illnesses and the spread of germs.

Rabbit Air Purifier Filters
The Rabbit Air MinusA2 uses 5 different filters and an ionizer as the last purification stage

It’s important to know that many types of ionic air purification create some level of ozone. Ozone in large quantities is dangerous to humans. If you do opt for an ionic air purifier make sure it creates zero or low levels of ozone.

Read our guide here on air ionizer dangers to better understand what to look for.

#4. Peco Filters

PECO systems use a propriety process called Photo Electrochemical Oxidation (PECO), which can eliminate indoor pollutants at a molecular scale.

Installing Molekule PECO filter into base of purifier
Molekule PECO filter

Although this filter is designed to destroy particles and not store them, you still need to periodically replace the filter.

Molekule air purifier PECO filter
Molekule air purifier PECO filter

MORE: Learn more about Molekule: Molekule Air vs Molekule Air Pro vs Molekule Mini

How much area can it cover?

The area coverage of any air purifier is laregely dependant on the size of the filter and / or the size of the unit itself. It takes power and generally a larger footprint to clean larger spaces.

Here’s an idea of how some of the top-rated air purifiers compare when it comes to area coverage.

ModelMax CoverageRead ReviewCheck Price
IQAir Atem150 sf.Read ReviewCheck Price
Coway 1512HH360 sf.Read ReviewCheck Price
Levoit Vital 100500 sf.Read ReviewCheck Price
Levoit LV H-134710 sf.Read ReviewCheck Price
Mila1,000 sf.Read ReviewCheck Price
Oransi EJ1201,250 sf.Read ReviewCheck Price

What can an air purifier filter out?

The exact particles that any given air purifier can remove vary greatly on the details of which model you go with.

HEPA filters on the Mila air purifier
Mila HEPA filters

In general, a good air purifier can eliminate particles down to 0.3 microns. HEPA filters that can perform to this level are generally rated H12. H13 rated HEPA filters remove 99.95% of airborne particulates.

This would include:

  • Allergens
  • Pollen
  • Pet Dander
  • Food Odor
  • Smoke
  • Etc.

NOTE: To eliminate unwanted odors, you’ll need to make sure you select an air purifier with a carbon filter. Carbon absorbs foul odors into the filter and is one of the best ways to keep smells at bay.

MORE: 5 Best Air Purifiers of 2021

Other Ways To Improve Indoor Air Quality

In addition to adding an air purifier, there are a few other ways you can improve the air quality inside your space. Some of the best strategies include:

#1. Add a plant.

Real plants that grow inside are known to have benefits on indoor air quality.

Some of the most popular varieties of air-improving plants include:

  1. Devil’s Ivy or Pothos
  2. Snake Plant
  3. Aloe Vera
  4. Chrysanthemums 
  5. Peace Lily or Flamingo Lily
  6. Philodendron
  7. Chinese Evergreen
  8. Ferns (Boston or Kimberly Queens)
  9. Pineapple Plant
  10. English Ivy

RELATED: For a complete list of what toxins are removed by each plant, check out the full guide here.

#2. Don’t smoke inside.

Smoking indoors is one of the fastest ways to greatly reduce your indoor air quality. Not only can it be hard to get the smell out, but it also can be hazardous to your health, especially indoors.

How to Smoke in Your Room Without Smelling It

Adding an air purifier with a carbon filter may help with the odor, but its certainly not failproof.

If you must smoke indoors you can follow this guide to help eliminate the smell.

#3. Keep Things Clean.

Keeping a dirty home can be another fast way to have really poor indoor air quality. Dirt, dust, debris, pet dander, and other allergens can easily build up on the floor and furniture, spreading to the air.

  • Pick up things from the floor
  • Regularly dust furniture
  • Regularly vacuum / mop floors
  • Clean up leftover meals
Ecovacs Deebot N8+ Pro robot vacuum

Taking care of the items on this short list in a timely manner can help limit excessive exposure to airborne particles, pests, allergens, and bacteria.

Not sure where to get started? Check out our guide for the best vacuums or keep it cheap and convenient with the best cheap robot vacuums.

Should You Buy an Air Purifier?

I would recommend adding an air purifier for people who:

  • Struggle with allergies: Seasonal allergies are one area where adding an air purifier can have a big impact. Many allergens are airborne and hard to clean since they don’t always attach to a surface. Air purifiers are designed to suck dirty air in and clean it, which can be a great way to address seasonal allergies.
  • Have pets: Pets bring a lot of love to a home, but also a lot of unwanted things as well—dirt, dander, bugs, and anything else they can shake off. If you have pets (even hypoallergenic pets), adding an air purifier can still be a good idea to keep your home feeling fresh.
  • Dislike strong odors: Does the neighbor in the apartment next to you frequently cook with strong odors? Does your roommate use too much perfume? Do your kids forget to shower? Air purifiers (with carbon filters) can be a great way to limit the presence of strong odors.

Best Air Purifier

Still not sure where to get started? Here’s a quick look at some of the top-rated air purifiers we’ve reviewed to date.

CategoryModelRead ReviewCheck Price
Best CompactCoway 1512HHRead ReviewCheck Price
Best CoverageOransi EJ120Read ReviewCheck Price
Best PerformanceRabbit Air Minus2Read ReviewCheck Price
Best ValueLevoit Vital 100Read ReviewCheck Price

If you still need more help finding an air purifier see our full list of tests and reviews here and find our favorite air purifiers here.


  • May 17, 2021 – Initial version of the page was published.

About Derek Hales

Derek HalesDerek Hales is the Founder and Editor-in-Chief of He has been featured in Fast Company, Reader's Digest, Business Insider,, She Knows, and other major publications. Derek has a Bachelor's Degree in Business Administration from Kansas State University. Hales has been testing and reviewing products for the home since 2014.

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