Asthma: Air Purifier Vs Humidifier Vs Diffuser


Asthma is an inflammatory disease which can be caused due to many allergens which can trigger the bronchoconstriction of the airways. The trigger caused as a result of the allergen turns into an adaptive immune response which develops an immunological memory of the allergen. Hence whenever the allergen is present in the atmosphere, the patient will suffer from symptoms of asthma.1

Bronchoconstriction refers to the narrowing of the airways in the lungs where muscle around the airways tightens due to an immune response initiated due to the allergens in the body. The narrowing of the airways thus causes many day-to-day issues where people with asthma, struggle to breathe and suffer with many implications of damaged or blocked airways.1

Airways can become damaged or blocked because of many reasons, such as:1

  • The obstruction of airways due to the overproduction of mucus, where the already narrowed airways become irritated due to lifestyle factors which trigger the inflammatory immune response consequently hyperproducing mucus, clogging it and furthering the impact of asthma
  • The inflammation of the airways caused due to the presence of allergens in the body, where the immune system reacts by sending lots of white blood cells to the irritated area (being the airways) thus leading to the inflammatory response mechanism which inflames the airways, hence causing damage
  • The remodelling of the airways which are also caused due to the inflammatory immune response which occurs as a result of the interaction between the body and the allergen. Remodelling of the airways refers to the permanent structurally pathological changes in the airways, in which they become permanently narrowed

In short, inflammatory cells predominantly mediate what happens to the airways, whether it be the fact that they are remodelled, inflamed, or obstructed.1

About asthma 


Asthma is characterised by particular symptoms which are known to be episodic. 

Many of which include:2

  • Coughing – which is caused due to the lack of oxygen being available to the red blood cells of the body (that are responsible for transporting oxygen all over the body). This occurs as a result of the narrowness of the arteries which does not allow efficient gas exchange
  • Wheezing – which is also triggered because of inefficient gas exchange taking place in the body. This can be due to an issue with the airways such as them being narrowed, obstructed, or remodelled
  • Shortness of breath – as the patient’s lung capacity is severely reduced due to a multitude of complications occurring in the airways. Thus, it takes longer to reoxygenate the whole body, especially during exercise, causing the patient to overexert their heart and hence cause shortness of breath
  • Intolerance in terms of exercise – meaning that the patient's exercising capability becomes limited. Exercising in healthy people, who do not have asthma involves the exertion of the respiratory system. However, people with asthma suffer from an intolerance to it, as they are unable to exercise normally due to reduced lung capacity and a lack of stamina caused due to inefficient gas exchange taking place
  • Tightness in the chest – this can occur when the respiratory system (heart and lungs) is being overexerted. This tightness can occur alongside chest pains as the body is having trouble keeping up with the body’s oxygen demand, thus the heart is overworking causing chest pains and tightness in the chest is caused due to the feeling of the constriction of the airways

What is an air purifier?

Effects of air purifiers on asthma

Can air purifiers help with asthma symptoms? How?

Air purifiers are devices which improve indoor air quality by eliminating air contaminants and thus can help alleviate the symptoms of asthma quite significantly. 

Choosing an air purifier for asthma

An ideal air purifier would need to be accessible so it can be easy to clean, Smart air purifiers are better because they can give an indication level as to how efficient they are and when they need to be cleaned as well as when their filters need to be changed. 

Pros and cons of air purifiers 

Pros include the fact that it rids the air of allergens which is the immediate cause of asthma, thus can help patients breathe better and improve the quality of life.6  This is because people would experience much less inflammation in their airways and so symptoms would be lessened.

On the other hand, cons include the fact that they are again high maintenance and would require frequent cleans upon usage as they can begin dispelling fungal spores if they are to become trapped in the machinery which can further exacerbate the asthmatic symptoms.6 Furthermore, they would need to be reviewed every once in a while, as their efficiency can drop if there’s a duct leakage6 as well as their filter having to be changed.

What is a humidifier?

Effects of humidifiers on asthma

Is a humidifier good for asthma symptoms? How?

Humidifiers are appliances that increase moisture levels in the air, hence increase the level of humidity. This can be both good and bad for people with asthma, though this depends on the context of the situation. Increasing humidity to an extent will reduce the impact of the symptoms of asthma however if it’s too humid, it can promote mould and thus furthering the number of allergens in the atmosphere. However, if it’s not humid enough, it can cause dry nasal passages and hence increase symptoms of asthma. So, an ideal humidity level is required in order for the desired effect to take place.5

Choosing a humidifier for asthma

An ideal humidifier would be easy to clean and easily accessible as the water would need changing quite frequently. Moreover, the water-containing part would have to be easily detachable to allow the rinsing of it. Overall, it would have to be an energy-efficient humidifier and thus a cost-effective one too.

Pros and cons of humidifiers 

Pros include the soothing effect of a humidifier which involves the moistening of airways, hence allowing better gas exchange to take place. This means that a patient would feel better as the symptoms would be slightly toned down ,especially with an ideal humidity level.5

In terms of the cons, studies show that the presence of a humidifier increases the risk of the development of asthma in adolescents4 as the devices are considered to be high maintenance. This means that they require to be cleaned to a high standard every three  days5 and if they’re not they can exacerbate symptoms. Their water would also need changing quite frequently as this can also cause high humidity hence promoting the growth of harmful pathogens in the house thus furthering the impact of asthma.

What is a diffuser?

Effects of diffusers on asthma

Is diffusing essential oils good for asthma symptoms? How?      

Aromatherapy is an ancient cultural technique used to benefit the health of the body and the mind. This is done so by using essential oils derived from plants and using a device called a diffuser to spread the aroma around the room.7 Tough studies show that this technique can aid people with anxiety, scientists’ advise allergy and asthmatic patients to avoid going down this route as it can cause asthma attacks, hives, irritation, and other issues.7

Choosing a diffuser for asthma

It’s best for people with asthma to avoid essential oil diffusers. However, a simple diffuser can be bought for aesthetic purposes, without the use of essential oils.

Pros and cons of diffusers 

Pros include the fact that they alleviate feelings of anxiety and have a calming effect.7

However, patients with asthma need to avoid contact with any allergens including ones that go straight into one’s respiratory organs such as the lungs. As these can irritate them significantly and cause severe coughing, wheezing, other allergic reactions and even result in an asthma attack, so are best avoided.7

Air purifier vs humidifier vs diffuser – Which is better?

Firstly, an easy one to eliminate is essential oil diff-users, these can cause more harm than good, especially for asthma symptoms, as they can aggravate symptoms and are best avoided.

So, it comes down to humidifier vs air purifier. Both Humidifiers and Air purifiers go hand in hand when it comes to being high maintenance, hence both would need regular cleaning as well as changing the water/filer, so in terms of maintenance, they are equivalent. Similarly, they can both spread and promote allergens in the indoor atmosphere, if left unchecked so would again need similar levels of monitoring. 

Though humidifiers can alleviate symptoms quite a lot and can be beneficial, they do not tackle the main issue of removing allergens. Air purifiers on the other hand, though unable to add moisture, do remove allergens and thus would be better suited to households of asthmatic patients.

Lifestyle tips to manage asthma symptoms

There are quite a few methods to reduce the impact of the symptoms of asthma, specifically certain lifestyle changes, that when put in place can make a real difference. 

Improving the quality of one’s diet can reduce the impact of asthma – this involves, consuming more wholegrain foods as well as vegetables and fruits which provide many antioxidants for the body, thus helping the body get rid of the allergens quicker.3 Also reducing the consumption of saturated fats aid in gaining weight and research shows that obesity aggravates symptoms and furthers other health complications.3

Maintaining a regular exercise schedule is also a good way to reduce the effect of asthma as it improves the lung function of patients meaning that it improves the lungs’ ability to effectively exchange gases, in short, opposes the symptoms of asthma to an extent which is very beneficial for the patient. It also improves the patient’s quality of life, as it reduces obesity and decreases the chances of the onset of other health conditions.3

As briefly mentioned above, weight loss is also recommended for asthma patients, as it can reduce their  quality of life. This means that losing weight would reduce pressure on the heart and in turn the lungs, resulting in healthier respiratory organs, that would improve the symptoms of asthma and even decrease their severity. There are plenty of other health benefits which would help in terms of managing asthma, as well as reversing it to an extent.3

Yoga, Meditation and breathing exercises have also shown scientific benefits to reducing the impact of asthma. As all three activities are known to improve lung function and thus can diminish peoples’ symptoms quite significantly.3

When to see a doctor

It is  considered best to see a doctor when episodic symptoms of coughing, wheezing, tightness in the chest, exercise intolerance, and Shortness of breath begin to occur.2 These would have to be consistent and effectively hinder  your day-to-day activities. 

Additionally, it is  best to see a specialist if and when you have pre-existing underlying health conditions impacting your respiratory organs (heart and lungs). These could include Chronic obstructive pulmonary disease (COPD), Rhinitis, Sinusitis, Nasal polyposis, and Atopic dermatitis.2 These conditions exacerbate the symptoms of asthma, hence immediate medical attention is to be sought, or else other health complications can ensue and further damage other parts of the body.


In summary, asthma is an inflammatory condition which affects the airways of a person by causing immune responses which lead to inflamed airways which cause the narrowing of airways and hence reducing the person’s ability to breathe. 

This impacts a person’s daily tasks as they experience persistent coughing and wheezing episode, as well as a tightness in the chest. If people are to experience this for an extended duration, they must consult a doctor immediately and try to implement changes in their lifestyle to reduce the impact of asthma. This could include eating healthy, exercising regularly and losing weight.

In terms of devices, they can use to alleviate asthma symptoms, air purifiers are the best bet as they rid the air of allergens which are the cause of asthma. Though humidifiers can alleviate symptoms too, they do not tackle the root cause of asthma and essential oil diffusers are not recommended as they can make conditions worse.


  1. Hamid Q, Tulic M. Immunobiology of Asthma. Annual Review of Physiology. 2009 Mar 1;71(1):489–507.
  2. National Heart, Lung, And Blood Institute. National Asthma Education Program. Expert Panel On The Management Of Asthma. Guidelines for the diagnosis and management of asthma. Bethesda, Md.: National Asthma Education Program, Office Of Prevention, Education, And Control, National Heart, Lung, And Blood Institute, National Institutes Of Health; 1991.
  3. Stoodley I, Williams L, Thompson C, Scott H, Wood L. Evidence for lifestyle interventions in asthma. Breathe. 2019 Jun;15(2):e50–61.
  4. McConnell R, Berhane K, Gilliland F, Islam T, Gauderman WJ, London SJ, et al. Indoor Risk Factors for Asthma in a Prospective Study of Adolescents. Epidemiology [Internet]. 2002 [cited 2022 Jul 29];13(3):288–95. Available from:
  5. Clinic M. Humidifiers: Why you might need them [Internet]. Mayo Clinic. 2019. Available from:
  6. Sublett JL. Effectiveness of Air Filters and Air Cleaners in Allergic Respiratory Diseases: A Review of the Recent Literature. Current Allergy and Asthma Reports. 2011 Jul 20;11(5).
  7. Halligudi N, Al Ojaili M. Page6 Page6 Page6 Page6 The Science and Art of Aromatherapy: A Brief Review. REVIEW ARTICLE Journal of Biomedical and Pharmaceutical Research. 2013;2(2):6–14.
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

Get our health newsletter

Get daily health and wellness advice from our medical team.
Your privacy is important to us. Any information you provide to this website may be placed by us on our servers. If you do not agree do not provide the information.

Bhavyaa Ojha

Bachelor's degree, Medical Neuroscience, University of Sussex

Bhavyaa is dedicated to achieving a career in the sciences. Experienced as a Domiciliary Care worker, Healthcare Article Writer and Academic Tutor.

Leave a Reply

Your email address will not be published. Required fields are marked * presents all health information in line with our terms and conditions. It is essential to understand that the medical information available on our platform is not intended to substitute the relationship between a patient and their physician or doctor, as well as any medical guidance they offer. Always consult with a healthcare professional before making any decisions based on the information found on our website.
Klarity is a citizen-centric health data management platform that enables citizens to securely access, control and share their own health data. Klarity Health Library aims to provide clear and evidence-based health and wellness related informative articles. 
Klarity / Managed Self Ltd
Alum House
5 Alum Chine Road
Westbourne Bournemouth BH4 8DT
VAT Number: 362 5758 74
Company Number: 10696687

Phone Number:

 +44 20 3239 9818