Can Using an Air Purifier Treat the Symptoms of Asthma?

Asthma is a chronic medical condition that tightens and inflames the airways in the lungs. More than 25 million Americans—including more than 5 million children—have asthma. 

Asthma symptoms include wheezing, coughing, excess mucus, and chest tightness. These symptoms, as well as asthma attacks (when symptoms worsen), can be triggered by allergens (normally harmless substances that trigger an allergic reaction) and other irritants. 

It's no wonder that air purifiers can be so enticing. These devices purportedly remove indoor pollutants like dust, allergens, bacteria, and mold from the air and replace them with clean air. Understandably, many people with asthma wonder if putting an air purifier in their home can help ease their symptoms. You may be one of them.

Learn more about whether air purifiers address asthma symptoms, if they make symptoms worse, and how to treat them.

Air purifier

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Does an Air Purifier Help With Asthma Symptoms?

An air purifier is a device that uses a filter and a fan to trap small particles from the air and recirculate the room with clean air. It can remove many pollutants that trigger allergy symptoms, such as:

  • Ash
  • Bacteria
  • Dust mites
  • Fungus
  • Mildew
  • Pet dander
  • Pollen
  • Smoke

There are many different types of air purifiers. High-efficiency particulate air (HEPA) filters are able to capture 99.7% of all particles 0.3 microns or smaller. HEPA filters can be sold on their own or used in other systems, such as your heating, ventilation, and air conditioning (HVAC) system or vacuum cleaner. 

Other types of air purifiers include:

  • Electrostatic filters, which use a small static charge to attract and trap particles
  • Ultraviolet (UV) light filters, which kill bacteria and viruses with UV light
  • Ionizers/ion generators, which magnetize small particles

Air Purifier vs. Humidifier

While air purifiers clean indoor air, humidifiers add moisture to the air. If your asthma is triggered by dry air, a humidifier could potentially help you control your symptoms. However, humidifiers can promote mildew, bacteria, dust mites, and mold growth, which can make symptoms worse for some people with asthma.

Potential Benefits

The U.S. Food and Drug Administration (FDA) has not licensed any air purifiers as medical devices for the purpose of treating asthma. However, some research suggests that air cleaners can help control asthma symptoms by limiting exposure to common asthma triggers. Air purifiers might do this by:

  • Lowering the medication burden: In one 2020 study, daily use of an indoor air purifier in an elementary school decreased the concentration of pollutants in the air. Students with asthma had a lower “medication burden” as a result, meaning they didn’t have to take as many prescribed medications to control their asthma symptoms. 
  • Reducing the effects of secondhand smoke: A 2018 study showed that air purifiers lowered the amount of cotinine (the chemical your body makes after nicotine exposure) in the saliva of nonsmoking adults.
  • Reducing inflammation: A 2018 study showed that indoor air purifiers improved indoor air quality and lowered the level of lung inflammation among a group of adults with asthma. It concluded: "Indoor cleaning by air purifier seems (to be a) promising therapeutic option for patients with asthma and further study is needed to clarify" its role.
  • Improving quality of life: A 2018 review suggested that the use of air purifiers alone did not consistently improve the quality of life of people with allergies and asthma. However, the use of HEPA vacuums along with other measures, such as mold removal, did improve quality of life.

Are There Any Precautions to Using an Air Purifier for Asthma?

Avoid air purifiers that generate ozone, a chemical that can harm your health even at low levels of exposure. The U.S. Environmental Protection Agency (EPA) warns against purchasing ozone-producing air cleaners, which are usually electrostatic air filters or ionizers.

Ozone is an unstable gas molecule and it is a lung irritant. It can cause breathing problems, shortness of breath, chest tightness, throat irritation, and coughing. It can make asthma symptoms worse and put you at a higher risk of developing a respiratory infection.

Also, remember that air purifiers can’t remove every asthma trigger, such as outdoor allergens, gases, fumes, or mold caused by moisture. It’s always best to treat your triggers “at the source,” if possible.

Work From "the Outside In"

Stop outdoor air particles from becoming indoor air nuisances by:


  • Replacing old and energy-inefficient windows
  • Caulking window frames to keep moisture, mold, pollen, and insects out
  • Insulating your home
  • Sealing foundation cracks
  • Installing smooth flooring surfaces that can be easily dusted or damp-mopped (to stop dust mites and mold spores in their tracks)

Choosing the Right Filter

If you're ready to buy an air purifier, keep a few pointers in mind:

  • Check the label: If you want to buy a stand-alone HEPA filter or HEPA vacuum cleaner, make sure it’s labeled as such. A product labeled “HEPA-like” or “HEPA-style” is not the real deal. 
  • Ensure efficiency: If you’re buying a filter for your central air system, the Environmental Working Group (EWG) suggests looking for one with a Minimum Efficiency Reporting Value (MERV) rating of 10 or higher. MERV ratings refer to a device’s ability to trap particles between 0.3 and 10 microns.
  • Look for certification: Allergy Standards Limited (ASL) and the Asthma and Allergy Foundation of America (AAFA) have designated certain air cleaners as "CERTIFIED asthma & asthma & allergy friendly®" based on their ability to remove allergens from the air. AAFA-approved air purifiers also don’t produce ozone or reintroduce allergens back into the air. 
  • Keep size in mind: The EWG recommends that you buy a filter that can replace a room’s volume of air two to three times in an hour, based on its square footage.
  • Avoid noisy air cleaners: Some air purifiers are very loud. This is especially concerning because many people with asthma already deal with sleep difficulties. For your own comfort, make sure an air purifier runs at a comfortable volume.

How to Use an Air Purifier for Asthma

Some guidelines for using an air purifier may help you control your asthma symptoms:

  • Perform regular maintenance: Washable air filters are often cheaper, but they have to be cleaned regularly. If you don’t clean or switch out your air purifier on a regular basis, it can grow mold or reintroduce allergens into the air. This could make your asthma symptoms worse. Aim to replace your filter at least every three months. 
  • Use a fan: When possible, run your central air system with the fan on. This helps ensure that the air is constantly replaced and your space is well-ventilated.
  • Vacuum regularly: You should vacuum with a HEPA vacuum cleaner once or twice a week to reduce your exposure to allergens.
  • Monitor your symptoms: To see if your air purifier is helping you manage your asthma, monitor your symptoms with a daily diary. If you take peak flow measurements with a hand-held device, record and monitor these as well. Peak flow measures how air flows from the lungs.

Filters Can Fill Up Fast

A whole-house HEPA filter should be sized to your home and installed by a professional HVAC company. The filter should be changed once every three months.

Additional Remedies to Manage Asthma Symptoms

While an air purifier can help some people control their asthma symptoms, you can take other steps to stop asthma triggers in their tracks:

  • Take your asthma medications as prescribed.
  • Carry your rescue inhaler with you everywhere.
  • Exercise regularly and maintain a healthy diet.
  • Get help to stop smoking, if you haven’t already.
  • Talk to your primary healthcare provider about a referral to a specialist, such as an allergist
  • Create an asthma action plan with your provider so you know when to seek emergency medical help if you need it. 
  • Get the seasonal flu shot.

Other Home Remedies

In addition to using an air purifier, you can take these steps to improve indoor air quality and reduce your exposure to irritants, pollutants, and allergens:

  • Keep your doors and windows closed to avoid exposure to outdoor allergens, such as pollen.
  • Avoid wall-to-wall carpet and heavy drapes.
  • Wash stuffed toys, rugs, and bedding regularly.
  • Use plastic or allergen-resistant covers on your pillows and mattresses. 
  • Prevent pet dander by keeping your pets out of your bedroom, washing their toys and bedding often, and bathing your pets regularly.
  • Reduce moisture with dehumidifiers and air conditioning.
  • Never leave food out in the open; it may attract pests, such as cockroaches.

Summary

Air purifiers are supposed to remove pollutants, allergens, and irritants from the air and improve indoor air quality. There is some evidence that air purifiers can help people with asthma control their symptoms. If you wish to buy a purifier, consider the device's cost, size, efficiency, volume, certification, and effectiveness. Avoid ionizers and other air purifiers that produce ozone, which can irritate the lungs. 

To manage asthma symptoms and reduce exposure to allergens, you can also take measures like reducing moisture, keeping pet dander under control, vacuuming regularly, controlling pests, shutting doors and windows, and using allergen-free mattress covers.

A Word From Verywell

The Allergy & Asthma Network cautions that "no air cleaner or filter can do it all." It recommends going to the source of the allergen, whether it’s mold, dust mites, pets, or insects. Air filtration is only one of several measures that may ease allergy and asthma symptoms in children and adults.

Frequently Asked Questions

  • Which air purifier is best for asthma?

    High-efficiency particulate air (HEPA) filters are the best air purifiers for asthma symptoms. They're designed to remove more than 99.7% of small particles from the air—or at least those that are 0.3 microns or smaller. These particles include dust mites, mold spores, pet dander, smoke, pollen, and many other common pollutants and irritants that trigger asthma symptoms.

  • Which is better for asthma: a humidifier or an air purifier?

    There’s some evidence that air purifiers, which clean indoor air by removing small particles like pollutants and allergens, can help with asthma symptoms.

    Humidifiers add moisture into the air. While humidifiers can help some people whose symptoms are triggered by dry air, they can also potentially make asthma symptoms worse by promoting mold growth.

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17 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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