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How can air purifiers help with asthma?

Young girl with asthma sitting on the end of her bed, putting an inhaler in her mouth.
(Image credit: Getty Images/Justin Paget)

How can air purifiers help with asthma? Asthma is a common condition that affects approximately 25 million Americans – about 8% of adults and 7% of children. We don’t know what causes asthma, but there may be a combination of both genetic and environmental factors that make some people more predisposed to developing the condition. 

If you experience asthma symptoms you may be wondering what you can do to make day to day life smoother and symptom-free. Aside from doctor prescribed medication, there are a few things you can do to keep your environment low-irritant. An air purification system may help to keep your asthma triggers at bay, so make sure to read our guide to the best air purifiers if you’re thinking of investing in one. 

So, what are the main symptoms of asthma, and how can you control them? And how exactly can an air purifier help to keep your symptoms under control? We asked the experts.

Symptoms of asthma

Symptoms are also not always consistent between different people, so the way asthma presents in one person may be very different from how it presents in another. It is important to get a formal diagnosis if you suspect you may have asthma, so that medical professionals can provide you with the best care possible and prescribe you any medication you may need.

Symptoms of asthma include:

  • Shortness of breath
  • Chest tightness or pain
  • Wheezing (a particularly common symptom in children and often the first sign parents have that their child may be asthmatic)
  • Trouble sleeping caused by coughing or shortness of breath
  • Particular difficulty breathing with respiratory infections like a cold of flu

An asthma attack is a particularly dangerous part of the condition where the airways become inflamed and can swell up to the point that a person cannot breathe. The muscles around the airways contract and produce extra mucus which further narrows the airways, putting even more pressure on the respiratory system. 

There is no cure for asthma, but the condition can be managed. Most people with asthma have two types of medication; an inhaler for attacks or quick relief, which calms symptoms as they occur, and an inhaler they use daily as a preventative measure to avoid attacks. Quick relief inhalers generally contain beta-2-agonists, which helps to relax the airways and return breathing to normal. Preventative inhalers contain corticosteroids, which work by making the respiratory system less reactive to triggers, which in turn reduces the frequency of attacks and the severity of symptoms. 

Enesta Jones, a spokesperson for the US Environmental Protection Agency (EPA (opens in new tab)), recommends reducing indoor irritants to help lower asthma triggers. “Americans spend up to 90% of their time indoors, and indoor allergens and irritants play a significant role in triggering asthma attacks,” she says. “Triggers are things that can cause asthma symptoms, an episode or attack, or make asthma worse. If you have asthma, you may react to just one trigger or you may find that several things act as triggers. Be sure to work with a doctor to identify triggers and develop a treatment plan that includes ways to reduce exposures to your asthma triggers.”

Do air purifiers work for asthma?

Symptoms of asthma are often made worse by poor air quality. Airborne irritants such as dust, smoke, and pollen can trigger an asthma attack, which can be particularly dangerous for children. A 2015 review paper (opens in new tab) found that our homes can be full of these indoor contaminants and often outdoor pollutants end up inside, particularly if you live in a heavily populated area, causing further potential irritation. 

The World Health Organization carried out an investigation (opens in new tab) into how damp and mold can impact indoor air quality and found that the presence of mold exacerbated symptoms of asthma. Air purifiers are fantastic for cleaning the air in your home and reducing the amount of potentially harmful, asthma triggering pollutants. Air purifiers for asthma are helpful because of the filtration system inside them. Good ones usually contain one or more HEPA filters, which filter the air in your home to remove indoor pollutants such as dust, pollen, mold spores, and other allergens (opens in new tab). The cleaned air is then much cleaner and less likely to trigger an attack in someone with asthma. 

Jones also notes improvements to symptoms with air purifiers. “Multiple studies with portable HEPA air cleaners have found improvements in one or more allergy and/or asthma symptom(s),” she says.

Air purifiers for allergies: Image of woman at home

(Image credit: Getty Images)

Air purifier vs dehumidifier

If you’re looking to control your asthma symptoms, you may be wondering, are dehumidifiers good for asthma? However, this may actually make things worse. Some people find that dehumidifiers make the air too dry which can irritate their respiratory system and make them cough. 

A 2013 study (opens in new tab) found that dehumidifiers offered no significant benefit in helping to control or reduce symptoms of asthma. However, if your home is particularly damp and warm, running a dehumidifier periodically may help to lower humidity levels, keeping allergens like mold spores at a lower level. It’s better to treat dehumidifiers on a case by case basis – having one might work for you if your home is particularly damp, and try different running patterns and running times to find one that doesn’t dry the air out to the point that it triggers your asthma. 

How to choose an air purifier for asthma

So, what makes a good air purifier? There are two main types that are good for keeping your air clean if you have asthma. Air-sterilizing air purifiers trap and then destroy irritants, instead of trapping them in a filter that then requires changing. They are silent, but also tend to be able to clean less air than purifiers containing HEPA filters. For a small room with little foot traffic bringing in new air, an air-sterilizing purifier is probably the best option. 

However, for larger rooms with a lot of air movement from foot traffic, open windows, aerosol use or other polluting tools, an air purifier with a HEPA filter is the more practical option as they can cycle air much faster. HEPA filter air purifiers tend to make a little bit of noise, as there is a powerful fan pulling air through the filter and then cycling it back into the room, but they tend to be quiet and non-invasive, if not totally silent. The filter works by trapping contaminants in layers of fiberglass or paper, which need to be changed regularly to keep the machine working effectively. 

The EPA recommends (opens in new tab) avoiding filters that produce ozone, as this is a lung irritant and can worsen symptoms of asthma. They advise that in some cases, air cleaners that contain electrostatic precipitators, ionizers, UV lights without adequate lamp coatings, and plasma air cleaners may have the potential to emit ozone, so these are types of air purifier to avoid if at all possible. 

Lou Mudge
Health Writer

Lou Mudge is a health writer based in Bath, United Kingdom for Future PLC. She holds an undergraduate degree in creative writing from Bath Spa University, and her work has appeared in Live Science, Tom's Guide, Fit & Well, Coach, T3, and Tech Radar, among others. She regularly writes about health and fitness-related topics such as air quality, gut health, diet and nutrition and the impacts these things have on our lives. 

She has worked for the University of Bath on a chemistry research project and produced a short book in collaboration with the department of education at Bath Spa University.