Air Filters, Air Sterilisers and Air Purifiers - What’s the difference?

10th January 2022

As it’s looking highly likely that we’re soon going to be relatively restriction free as far as returning to the office is concerned, we thought that maybe the need for air purification might be on the wane. But then we came across some interesting articles that made us think again.


Firstly, whilst many anticipate the worst of the Omicron wave will soon be behind us, there is obviously a concern that new COVID variants are highly likely (we’ve seen four significant variants of concern (1) in the last 18 months but the severity of their impact on health is clearly difficult to anticipate.


The next article that grabbed our attention related to cognitive function and air quality (2). The most significant takeaway fact which hit me from this article was that cognitive function improves by 61% in areas with low concentrations of volatile organic compounds.


This led us on to more articles which referred to air quality being lower indoors (3) (4). Other studies on this subject estimated that pollution indoors can be between two to five times greater than outdoors.


I must admit, until I looked into this subject, I didn’t realise the weight of research into this topic was so significant, nor the business case for improving air quality so compelling. As with many things, I guess it’s often the case that something so basic, yet obvious is easily overlooked.

Air Quality Improvement

Arguably, as the world changes around us, new diseases and increased health risks associated with pollution means the need to purify air is more important than ever before.


Whilst an organisation’s responsibility to safeguard their employees is mandated in law, and not in question, the drive to enhance colleague wellbeing is intensifying. As the hybrid office model gains traction, the increasing level to which spaces are shared increases the risk of viruses, chemicals or allergens spreading.


In balancing the need to continually seek to improve employee wellbeing and manage risk, there are two main strategies businesses can implement as far as improving air quality is concerned. These are air purification and ventilation.


It quickly became apparent when I looked into this topic that there is an important distinction to be made between air purifiers and air sanitisers. An air purifier works by mechanically removing particulate matter from the air by some means of filtration. Purification can be accomplished in a few different ways. HEPA filters are one of the most common operating principles of air purifiers. Ionic purifiers are also common. Ionic purifiers work by charging dust particles and getting them to stick with electromagnetism. Through these means, air purifiers work to remove dust, allergens, and most air pathogens.


Air sanitizers work a little differently. UV sanitizers use ultraviolet light to destroy pathogens and neutralize some chemicals present in indoor air. Sanitization technology generally involve small, standalone units or in some instances, can be installed in-line with air conditioning ducts to sanitize the air in the whole building.


Ventilation involves replacing the air inside with “fresh” air from outside. The primary reason for this is to keep carbon dioxide levels down. Air purification devices are unable to filter out CO2 molecules due to their relatively small size (0.00065 microns) (5) when compared to things such as viruses (0.005 - 0.3 microns) (5).

A Practical Air Quality Improvement Solution

It seemed pretty obvious that the optimum air quality improvement solution involves ventilation, air filtration and air sterilisation, but finding the means of achieving it took a bit of looking into.


Whilst ventilation is fairly obvious, there seems to be a lot of smoke and mirrors around the technology behind air purifiers and in particular the distinction between filtration and sterilisation.


That said we did discover some neat air sterilisation units which combine filtration (Medical grade HEPA filters alongside activated carbon filters) which remove larger particles and UV-C lamps that kill up to 99.97% of airborbne pathogens and viruses.


The units themselves are portable, low noise (<65db) and come in two sizes: W575 H1335 D335mm and W490 H729 D244mm. The smaller unit caters for spaces up to 90m2 and the larger one covers spaces up to 150m2 (Both based on ceiling height up to 2.8m).

Further Information

If you’d like more information on this topic or further details on the air filtration and sterilisation units we’ve introduced into our portfolio drop please contact us and we’ll do what we can to help.