Air purifiers have become an essential part of our lives, especially considering the increasing pollution levels. They play a crucial role in improving the air quality in our homes and offices. The key to their effectiveness lies in the type of filter they use. This article will delve into the world of air purifier filters, their types, and how they contribute to cleaner air.

The Importance of Air Filters in Air Purifiers

Air filters are the heart of air purifiers. They trap pollutants and particles, preventing them from re-circulating in the room. The Environmental Protection Agency (EPA) states that the concentration of certain pollutants can be two to five times higher indoors than outdoors. This makes air purifiers, and by extension, air filters, an essential tool in maintaining indoor air quality and reducing health risks associated with poor air quality.

Types of Air Filters

HEPA Filters

High-Efficiency Particulate Air (HEPA) filters are among the best options for filtering out small particles like dust, allergens, and bacteria. They capture 99.97% of particles larger than 0.3 microns, making them highly effective at improving indoor air quality. However, not all HEPA filters are created equal. There are different ranks, such as H13 and H11, with higher ranks indicating better performance but also a higher price tag.

Activated Carbon Filters

Activated carbon filters work differently from HEPA filters. They absorb odors and chemicals rather than just trapping them. These absorbent materials attract unwanted elements, ensuring the air we breathe smells better too!


Many devices include pre-filters that trap larger particles before they reach the primary filter. This feature extends the lifespan of other internal parts, creating value.

Mechanical Filters

These purifiers use fans to force air through a dense web of fine fibers that trap particles. Filters with very fine mesh are called HEPA filters. While they work on microscopic particles, they can also remove larger particles when they’re suspended in the air.

Activated Carbon Filters

Unlike mechanical filters, these filters use activated carbon to capture certain types of gases, including some odor-causing molecules. But they’re not particularly effective against formaldehyde, ammonia, or nitrogen oxide.

Ozone Generators

These machines produce ozone, a molecule that can react with certain pollutants to alter their chemical composition. This can result in dangerous indoor air quality, and it’s not recommended to use these types of air purifiers.

Electrostatic Precipitators and Ionizers

In these electronic models, particles in the air become charged so that they stick—magnet-like—to plates on the machine or to nearby surfaces. However, they can produce ozone, which is harmful.

Ultraviolet Germicidal Irradiation (UVGI)

Some manufacturers claim that their air purifiers kill airborne viruses, bacteria, and fungal spores with UV lamps. But they might miss certain bacteria and mold spores that are resistant to UV radiation.

Photocatalytic Oxidation (PCO) and Photoelectrochemical Oxidation (PECO)

Some air purifiers use ultraviolet radiation and a photocatalyst, such as titanium dioxide, to produce hydroxyl radicals that oxidize gaseous pollutants. Depending on the pollutant, this reaction can generate harmful byproducts.

Choosing the Right Air Filter

When it comes to maintaining good air quality inside your home, the choice of air filter plays a crucial role. The air filter is a small, often inexpensive part of your heating and cooling systems that keeps them running smoothly. It also helps to capture hair, dust, and other debris that circulates around your house.

The choice of air filter depends on your specific situation. Do you live with pets? Is the air dry? Are there mold issues or specific allergies? If you’re looking for a purifier to improve indoor air quality and reduce health risks, consider investing in one with a HEPA filter, preferably one ranked H11 or higher if possible. For removing unpleasant smells from your home or office, an activated carbon filter might be a better option.

Filter TypeBest For
HEPA FilterImproving indoor air quality, reducing health risks
Activated Carbon FilterRemoving unpleasant smells

The Role of Air Purifiers in Removing Viruses

While some air purifiers claim to have UV-C or other technologies that can capture or kill viruses, it’s important to note that no single device can completely eliminate all types of airborne contaminants. However, a high-quality HEPA filter can effectively capture small particles that may contain viruses and help improve overall indoor air quality.

Air Purifier TypeEffectiveness
UV-CLimited, cannot eliminate all airborne contaminants
HEPA FilterCan effectively capture small particles, including those that may contain viruses

It’s important to remember that an air purifier can only filter the air in the room that it’s located in, so air in other parts of the house can remain untreated. And any droplets that settle onto surfaces won’t end up going through the air purifier. So it’s still very important that you keep up the usual hygiene practices: washing your hands, cleaning hard surfaces, and, of course, trying to avoid bringing germs into your home in the first place.

Activated Carbon Filters and Odor Removal

Activated carbon filters are most commonly used to remove gases and odors from the air. They work by trapping gas molecules on a bed of charcoal. This process, known as adsorption, allows carbon air filters to filter organic chemicals (gases) from the air. However, they cannot remove fine particles like mold, dust, or pollen from the air.

Filter TypeCan RemoveCannot Remove
Activated Carbon FilterGases, OdorsMold, Dust, Pollen

Air Purifiers vs. Air Cleaners

Air purifiers and air cleaners both aim to improve indoor air quality, but they do so in different ways. Air purifiers use filters, like HEPA or activated carbon, to trap and remove contaminants from the air. Air cleaners, on the other hand, often use methods like ionization or UV light to neutralize airborne particles. However, these methods are generally less effective at removing contaminants than HEPA filters.

Air PurifierUses filters to trap and remove contaminantsMore effective
Air CleanerUses ionization or UV light to neutralize airborne particlesLess effective

Air Purifiers and Virus Removal

Air purifiers with a HEPA filter can help remove small particles from the air, including those that may contain viruses. However, they won’t necessarily catch them all or kill them. Even if trapped, the virus may stay alive on the filter surface for several hours or even days.

DeviceCan DoCannot Do
Air Purifier with HEPA FilterRemove small particles, including those that may contain virusesCatch all viruses, Kill viruses

HEPA Filter Ratings and Benefits

HEPA filters are categorized with a numbering system, with higher grades providing a finer mesh and capturing more particulates from the air. For example, a HEPA H10 filter captures 85% of particles over 0.5 microns in size, while a HEPA H13 filter captures 99.97% of particles over 0.3 microns in size.

HEPA Filter GradeEfficiency
H10Captures 85% of particles over 0.5 microns
H11Captures 95% of particles over 0.5 microns
H12Captures 99.5% of particles over 0.5 microns
H13Captures 99.97% of particles over 0.3 microns

To most effectively remove allergy-causing pollutants from the air in your home, it’s recommended to use a purifier with the latest HEPA filtration technology.


Improving indoor air quality is a vital part of maintaining a healthy living environment. An air purifier with the right type of filter can make all the difference. By choosing a device that utilizes high-quality filters suited to tackling common pollutants in your environment, you can significantly improve the air you breathe.


What type of air filters should I use in my air purifier?

HEPA (High Efficiency Particulate Air) filters are the most effective at removing small particles such as dust, pollen, and pet dander. Activated carbon filters are also commonly used to absorb odors and chemicals.

How often do I need to change the air filter in my air purifier?

It depends on the model and usage frequency. Generally, HEPA filters should be changed every 6-12 months, while activated carbon filters may need to be replaced more frequently. Check your manufacturer’s guidelines for specific recommendations.

Can an air purifier remove viruses from the air?

While some air purifiers claim to have UV-C or other technologies that can capture or kill viruses, it’s important to note that no single device can completely eliminate all types of airborne contaminants. However, a high-quality HEPA filter can effectively capture small particles that may contain viruses and help improve overall indoor air quality.


Hey there, I'm Kevin, editor of Xievo. I'm passionate about air purifiers and providing accurate information to help readers make informed decisions. In my free time, I love hiking and experimenting with air purifiers in my own home. Thanks for visiting Xievo!