Air purifiers for allergies

Air filters and purifiers capable of helping remove methylisothiazolinone and other VOCs from an internal environment have been a topic of recent interest on the MI allergy Facebook groups.

Because filtration can tackle a number of allergens — pollen, pet dander, mold, dust mite, chemicals, fragrances etc — I recently examined the issue in detail on my more general Allergy Insight website, including some suggestions for products to try.

You can read the full article here, but I’ll summarise my brief thoughts specific to isothiazolinone allergies below.


1/ HEPA-only filters probably won’t help …
HEPA filters filter out particulates — particles such as pollens — and although this may help reduce your hay fever symptoms, and symptoms to any other non-chemical allergies, they can’t filter smaller chemical molecules such as the isothiazolinones, and therefore any help they can provide will be modest at best. There are actually relatively few HEPA-only purifiers now on the market, as most now come with some form of carbon mechanism …


IQAir HealthPro Plus

2/ Carbon / charcoal filters may help … 
Activated carbon / charcoal filters should, in theory, work well in absorbing isothiazolinones, although research, claims and confirmation appears to be lacking. All incorporate HEPA (or HEPA-like) filtration technology.

One of the best on the market — which has some good anecdotal reports from sufferers — is the IQAir HealthPro 250 (UK), which has a triple HEPA / activated carbon / ‘hyper HEPA’ system.

There’s also the slightly cheaper but similarly equipped IQAir HealthPro, and the more affordable IQAir HealthPro Compact (US). In the UK, this seems to be known as the IQAir HealthPro 150.

This seems to be the best option if you have only isothiazolinone allergies and perhaps fragrance allergies to consider (fragrance allergens are quite large chemical molecules).


3/ ‘Boosted’ carbon / charcoal filters may help with additional allergies …
If you have additional chemical allergies to small molecules such as formaldehyde, or other concerns beyond allergens (eg carbon monoxide), then you may benefit from looking at models which not only have HEPA and activated carbon, but additional technologies too.

One is called zeolite: a mineral mix of silicons, aluminium and oxygen, which may give a boost in additionally helping to absorb ammonia, formaldehyde (which many have allergies to) and carbon monoxide, which is toxic and which activated carbon does not absorb particularly well. The Austin Air HealthMate Plus (US) / Austin Air HealthMate Plus (Can / UK) comes with zeolite technology, and is available in smart white, midnight blue, black and sandstone options. 

Also receiving good anecdotal reports on social media are the newest models Dyson trio of Cool Tower, Cool Desk and Hot and Cool Link — which contain a chemical ‘boost’, called tris, to further improve the absorption of formaldehyde and nitrogen dioxide, both small molecules. See the Dyson website to learn more about them. An option such as this may be the better choice if you have multiple chemical sensitivities including to formaldehyde. 


Don’t expect filters to be a magic bullet, and once you’ve thought about the allergens you wish to filter, you need to give personal consideration to room size, noise levels, costs of replacement filters and so on. If anyone has experiences they’d like to share, please leave them below. 

You may also be interested in ‘personal’ filters — i.e. face masks — which may be useful in certain circumstances, and obviously constitute a more affordable initial investment. Click here to see our previous article on them. 


  1. Elise

    The best air purifier on the market is Molekule. It’s a worthwhile investment, and gets rid of all the allergens in the air using molecular technology. We’ve had ours since March and love it.

    1. MI Free (Post author)

      Very interesting – thanks. I’ve heard there can be some problems with oxidisers for those with certain allergies, but do note from their site that ozone is not increased (and in fact reduced) which is reassuring. Has anyone else tried Molekule?


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