Most of us spend a significant amount of our day inside. These indoor spaces can be full of air pollutants that aggravate conditions like allergies and asthma.

Air purifiers are portable devices that you can use in an indoor space to reduce unwanted air particles. There are many types of purifiers available.

We asked an internist about what to look for in an air purifier, and what types of air purifiers she recommends for allergies. Read on to learn more.

Dr. Alana Biggers, assistant professor of medicine at the University of Illinois-Chicago, believes that air filters can be useful for those with allergies because they remove a majority of aggravating air particulates from any given room, though they do not take away all particles. They filter what’s in the air and not pollutants that are settled into walls, floors, and furnishings.

If you decide to purchase an air purifier to reduce allergy symptoms, keep in mind that devices can vary. It’s important to consider what air pollutants you’d like to filter, and the size of the room you’ll be using it in.

What are you hoping to filter?

“There are many types of air filters that can remove particles at varying degrees. For example, HEPA filters, UV air filters, and ion filters are very good at removing dust, danger, pollen, and mold but they are not great at removing odors,” notes Biggers.

She adds, “Carbon-based filters are good at filtering some particles and odors, but are not as effective in removing dust, danger, pollen, and mold.”

This table breaks down the different types of air filters and how they work.

Types of air filtersHow they work, what they target
high-efficiency particulate air (HEPA)Fibrous media air filters remove particles from the air.
activated carbonActivated carbon removes gases from the air.
ionizerThis uses a high-voltage wire or carbon brush to remove particles from the air. The negative ions interact with the air particles causing them to attract to the filter or other objects in the room.
electrostatic precipitationSimilar to ionizers, this uses a wire to charge particles and bring them to the filter.
ultraviolet germicidal irradiation (UVGI)UV light inactivates microbes. This does not pull out the microbes from the space entirely; it only inactivates them.
photoelectrochecmical oxidation (PECO)This newer technology removes very small particles in the air by making a photoelectrochemical reaction that removes and destroys pollutants.
permanently installed air cleanersNot considered air purifiers (which are portable), heating, ventilation, and cooling (HVAC) systems and furnaces can remove pollutants from the air. They may use filters like the ones listed above, and they may also include an air exchanger to clean the air.

How big is the area you’d like to filter?

The amount of space in your room should also guide your selection. Check the amount of square feet a unit can handle when evaluating it.

You can look for the clean air delivery rate (CADR) to determine how many particles and square feet an air purifier can reach. For example, HEPA filters can clean the smallest particles like tobacco smoke and medium and large particles like dust and pollen out of the air and may have a high CADR.

What’s the difference between an air purifier and a humidifier?

Air purifiers and humidifiers are very different devices. An air purifier removes particles, gases, and other pollutants from indoor air making it cleaner to breathe. A humidifier adds moisture or humidity to the air without doing anything to clean the air.

Healthline

There are many air purifiers on the market. The following products have allergy-specific features and strong consumer reviews.

The price key is as follows:

  • $ – Up to $200
  • $$ – $200 to $500
  • $$$ – More than $500

Dyson Pure Cool TP01


Price: $$

Best for: Large rooms

The Dyson Pure Cool TP01 combines a HEPA air purifier and a tower fan in one, and it can handle a large room. It claims to remove “99.97% of allergens and pollutants as small as 0.3 microns,” including pollen, dust, mold spores, bacteria, and pet dander.

Molekule Air Mini

Price: $$

Best for: Small spaces

Molekule air purifiers use PECO filters, which are designed to destroy pollutants, including volatile organic compounds (VOCs), and mold. The Molekule Air Mini works well for small spaces, like studio apartments, kids’ bedrooms, and home offices. It claims to replace the air in a 250-square=foot room every hour.

Honeywell True HEPA (HPA100) with Allergen Remover

Price: $

Best for: Medium-sized rooms

The Honeywell True HEPA air purifier is ideal for medium-size rooms. It has a HEPA filter and claims to capture “up to 99.97 percent of microscopic allergens, 0.3 microns or larger.” It also includes a carbon pre-filter that helps reduce unpleasant odors.

Philips 5000i

Price: $$$

Best for: Large rooms

The Phillips 5000i air purifier is designed for large rooms (up to 454 square feet). It claims to have a 99.97 percent allergen removal system, and also protects against gases, particles, bacteria, and viruses. It uses two HEPA filters for double air-flow performance.

RabbitAir MinusA2 Ultra Quiet

Price: $$$

Best for: Extra-large rooms

The RabbitAir’s MinusA2 Ultra Quiet air purifier targets pollutants and odors and features a six-stage filtration system that includes a HEPA filter, activated charcoal carbon filter, and negative ions. It works in rooms up to 815 square feet.

You can mount it on your wall, and it can even feature a work of art so can double as room décor. It can be customized for your needs to focus on the concerns in your home: germs, pet dander, toxins, odor. Finally, you can use an app and Wi-Fi to control the unit when you’re away from the house.

Levoit LV-PUR131S Smart True HEPA

Price: $

Best for: Medium-sized to large rooms

The Levoit LV-PUR131S Smart True HEPA air purifier features a three-stage air filtration process that includes a pre-filter, HEPA filter, and an activated carbon filter. These filters help remove pollutants, odors, pollen, dander, allergens, gases, smoke, and other particles from your indoor air.

Use a smartphone app to program the Wi-Fi enabled air purifier and put it on different automatic modes, depending on the air quality in your home, or if you want it to run quieter at night. It’s also compatible with Alexa.

Air purifiers can target many allergic triggers. While there’s no official recommendation for the use of air purifiers for allergies, many medical experts and research studies point to their effectiveness.

What the research says

The Environmental Protection Agency (EPA) refers to several studies that link the use of air purifiers to allergies and asthma symptom relief. The EPA cautions that these studies don’t always point to significant improvements or a reduction in all allergy symptoms.

  • A 2018 study found that a HEPA air purifier in a person’s bedroom improved the symptoms of allergic rhinitis by reducing the concentration of particulate matter and house dust mites in the air.
  • A 2018 study following people using air purifiers with PECO filters found that allergy symptoms decreased significantly.
  • A 2018 study examining people with asthma triggered by dust mites concluded that air purifiers were a promising therapeutic option.

If you’re experiencing allergy or asthma symptoms inside your house, an air purifier may help reduce your symptoms by cleaning the air.

There are many different brands and models of air purifiers. Determine your specific filtration needs as well as the size of your room before purchasing an air purifier.