Asthma Air Purifier

Asthma Air Purifier

Whether you have mild or severe asthma, an asthma air purifier will help to reduce your exposure to asthma triggers in the form of airborne pollution and thus will help you to control your asthma symptoms.

A good asthma air purifier will reduce levels of common household allergens such as dust mite, dust, pollen, pet dander and mould, as well as odours, gases, chemicals and general traffic pollution. This article will discuss the relevant information you need to know when purchasing an asthma air purifier.

Frequently Asked Questions

Asthma Triggers

Asthma can be triggered by a very broad range of common household allergens, such as dust, pollen, dust mite, mould, and pet dander, as well as by tobacco smoke, traffic pollution and other gases and chemicals. Understanding the size and type of asthma triggers there are is vital as this will help you identify which asthma air purifier you need.

Tobacco Smoke:
Tobacco smoke releases large quantities of chemicals, particulates and odours. A good asthma air purifier will be able to remove all three contaminants from the air. There are around 7,000 chemicals in tobacco smoke, such as tar, formaldehyde, benzene, arsenic and cadmium. Tobacco smoke particles range from 0.01 - 90 microns in size.

Traffic Pollution:
Traffic pollution consists of ultra-fine particles at 0.001 – 0.3 microns in size, including black carbon, as well as a broad range of chemicals such as VOCs, carbon monoxide, nitrogen, and sulphur oxides. Traffic pollution can inflame the lungs and increase the airway resistance in all people, and the effects on people suffering with asthma are significantly more severe.

Smog can add to the existing traffic and air pollution. However, smog is visible as it is a combination of fog and smoke and is easily identified by the thick foul smelling, dirty-yellow characteristics. Breathing in smog is harmful towards everyone, not just asthma sufferers as smog is a mixture of industrial pollution, transportation emissions, photochemical smog and natural causes such as a volcano erupting. When certain chemicals mix with water and air they turn into acid, causing skin irritations, breathing problems and even corrode buildings.

VOCs (Volatile Organic Compounds) are gases which are emitted from natural or man-made solids or liquids. VOCs can be found in many everyday products such as vehicle fuel, building materials, photocopier toner, air fresheners, engineered wood products and paint. Some VOCs have a distinctive smell so you are aware of what it is, such as paint or gasoline, whilst other VOCs are undetectable. VOCs can cause asthma symptoms at any time of the year. VOCs can also contribute to the nose, eye and throat irritations as well as headaches, loss of coordination, nausea, and damage to the liver, kidney, and central nervous systems. A good asthma air purifier will effectively control a wide range of VOCs and the only appropriate way to do so is for the asthma air purifier to use high quality activated carbon.

Natural Allergens:
Natural allergens include dust mitedustpollenmould spores and pet dander; all of which can cause asthma symptoms. The severity of the reaction can differ greatly and the particle size for natural allergens varies. For example, dust mite droppings are 0.1 – 40 microns in size while pollen grains are 3 – 100 microns in size. However, some pollen grains can break into fragments of 0.4 - 1 micron in size. Dust particles are between 1 - 90 microns in size and are made up of human skin, soil and dirt. The flakes of dead pet skin, saliva and dried urine (better known as pet dander) are about 0.1 - 10 microns in size. Mould spores are between 3 – 200 microns in size and can be found anywhere in the house. Natural allergens are relatively easy to filter out of the air, however, the key for an asthma air purifier is that the unit is leakage free – otherwise, allergens will pass the filter and will be released back into the air.


The number of air exchanges an asthma air purifier can complete within an hour is important, as well as the level of filtration efficiency it achieves. The filtration efficiency of an asthma air purifier should be HEPA standard (i.e. 99.95% at 0.3 microns) or higher. What number of air exchanges the asthma air purifier should produce depends on the contamination levels and the severity of the asthma condition. The filtration efficiency of an asthma air purifier should also be as consistent as possible, and should not reduce over time. A decrease in the filtration efficiency of the asthma air purifier will result in lower air quality within the environment.

Suitable Technology

There is a range of filter technologies advertised for asthma air purifiers but the only one that will effectively remove the particulate, gas and chemical contamination mentioned above, is the combination of the granular activated carbon filter and a HEPA filter.

Granular Activated Carbon Filter:
The granular activated carbon filter combines with various minerals such as zeolite and some carbon is impregnated with potassium iodide or active alumina. This increases the adsorption quantities within the carbon, making odours, vapours and other chemicals attach to the surface of the carbon when they pass next to it.

The use of a HEPA filter is recommended for reducing asthma triggers such as pollen, dust mite, bacteria, viruses, pet dander, tobacco smoke and traffic pollution. HEPA filters are capable of capturing 99.97% of all airborne particulates at 0.3 microns.

Ionisers work by creating a static charge around the airborne contaminants floating within the room. Once the particles have been charged they stick to surfaces they come close to. We do not recommend asthma air purifiers that use ionisation as the ionisation process can release ozone as a by-product into the atmosphere, which can function as an asthma trigger. Furthermore, the filtration efficiency of ionisers decreases over time, not giving you the certainty that the asthma air purifier’s filtration efficiency is as high as required.

Filters using the combustion method simply incinerate pollution. However, when pollution is incinerated it is not filtered out of the air but released back into the environment, which is unacceptable for people with asthma or other respiratory conditions. The other problem with combustion technology is that it tends to produce insufficient amounts of air changes per hour.

Other considerations

Granular Activated Carbon:  The carbon filter should consist of large amounts of granular activated carbon in order to effectively eliminate VOCs, gases and chemicals. A carbon mesh (rather than granular activated carbon) will be less effective. An IQAir GC MultiGas, for example, uses up to 5.4kg of granular activated carbon whilst the V5-Cell MG filter used in the IQAir HealthPro 250 has 2.5kg of granular activated carbon to reduce gases and chemical pollution.

Leakage:  It is important that an asthma air purifier is leakage free, i.e. that the entire system filtration efficiency is as high as possible. A leakage free air purifier ensures that all the polluted air passing through the unit also passes through the filters and is properly cleaned. An asthma air purifier that is not leakage free allows pollution to escape past the filters.

Which air purifier is best for asthma?

Unfortunately, the air purifier industry in the UK is not regulated.  So, you can sell more or less anything as an 'asthma air purifier' and make misleading and sometimes false claims about it. When looking for an asthma air purifier to help ease your asthma symptoms, we recommend looking for one that offers high filtration efficiency and also a significant amount of activated carbon to remove gases and chemicals. The asthma air purifier should also have been tested by an independent testing company, in a real size room - so that you can compare its actual performance against other air purifiers. TheIQAir HealthPro 250is a medical grade asthma air purifier, with the highest filtration efficiency, and independently tested, certified and guaranteed performance.  It is one of the market’s very best rated professional asthma air purifiers. 

Can air purifiers make asthma worse?

If you use an air purifier that uses a technology that produces unwanted by- products (such as ozone or charged particulates) then that 'air purifier' could make your symptoms worse.  A professional asthma air purifier, however, should only use HEPA filtration, as it will be completely free of any by-products, and thus will help to reduce airborne pollution that might trigger your asthma symptoms. Asthma air purifiers with efficient and effective filtration are capable of significantly reducing the number of pollutants in the air that could otherwise be inhaled by the person suffering with asthma.

Do air purifiers help with asthma?

A professional asthma air purifier is a great way to help reduce the amount of airborne pollution in your home, and thus reduce the amount of asthma triggers that you might get in contact with.  Asthma symptoms can be triggered by household allergens such as dust, pollen, mould spores, pet dander, traffic soot, cleaning products and more. An effective asthma air purifier will purify the air in your home several times and hour and capture these pollutants - leaving you to breathe cleaner air.


The best asthma air purifier that we would recommend is the IQAir HealthPro 250:

The IQAir HealthPro 250 is IQAir’s asthma specialist. As the unit is designed for people with respiratory problems, it is 100% ozone free, and its HyperHEPA filtration removes virtually all particulate pollution, as well as the broadest range of chemical and gas contamination.

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