How Does A HEPA Filter Work?

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We often talk about HEPA filters but never discuss them in detail. This blog post talks about HEPA filters and how a HEPA filter works. 


What is a HEPA Filter? 

HEPA is an acronym for high-efficiency particulate air [filter]. Before HEPA became a part of air filtration technology, it was a secret government project. Its history dates back to the era when the British found it as a paper piece in German gas masks during the early days of World War 1.

It stood out for its ability to perfectly capture chemical smoke. The idea was replicated by the British and later used as mechanical filtration in headquarters.

In the 1950s, HEPA was officially available as a commercial air purification filter. According to the Environmental Protection Agency, HEPA air filters can filter 99.97 per cent of air, extracting airborne bacteria and viruses, mould, dust and pollen particles of size as small as 0.3 microns.

Different regulatory authorities recommended HEPA air purifiers for installation in commercial spaces during the pandemic due to their efficiency and effectiveness in preventing virus transmission.

They have also been cited as ideal in cleaning the space and making it friendly for asthma and allergic patients. 


How Does a HEPA Filter Work? 

Let’s talk about how does a HEPA filter work.  

True HEPA filters feature borosilicate glass or plastic fibres with a randomly-arranged fibrous maze. These air filters do not filter smaller particles like a sieve but trap them using one of the following methods – impaction, straining, diffusion or interception.  

Direct impaction is used to trap large particles, such as pollen, mould and dust. By large, we are referring to particles of size 10 microns. 

Also known as sieving, straining occurs when particles get stuck between two fibres.  

Interception is for mid-sized particles that are neither large enough for inertia nor small enough to diffuse. These particles follow the stream of the airflow and stick to the fibre sides. 

Diffusion is for smaller particles of size less than 0.3 microns. These particles move in a random pattern, causing them to hit the fibres and stick to them.

It involves the theory of Brownian motion, which refers to the random movement of particles after their collision with gas molecules. 


When Should You Use a HEPA Filter? 


To Prevent Allergies

HEPA air purifiers are ideal for your home if you have asthma or allergies. It is because they effectively filter mould, pollen, pet dander, allergens and bacteria from the space and provide allergy relief.

Other ways to support relief include replacing carpets with tiles, keeping pets outdoors, changing sheets frequently and vacuuming daily. 


To Filter Dust 

If you are the owner of a commercial space, like a manufacturing site, warehouse facility or workshop, you should make necessary arrangements to keep your employees safe.

A dusty working environment can negatively impact workers and decline their health and well-being. HEPA air purifiers are the best to extract large and small dust particles from the environment and make it safe for breathing. 


To Prevent Viruses and Bacteria 

The deployment of HEPA air purifiers enabled the global commercial sector to resume its activities after a strict lockdown during the pandemic.

The regulatory authorities, like the EPA, recommended the use of HEPA air purification technology in schools and offices to prevent the transmission of COVID-19.

The virus was declared airborne, and HEPA has been found effective in extracting airborne particles that remain in the air for a long time.     

Reach out to us for more information if you are looking for the best air purifier for commercial or residential use.