What is a HEPA filter and what are their benefits?

A HEPA filter is  a specific type of high quality air filter that meets the HEPA filter standard, which is to remove at least 99.97% of particles from the air down to at least 0.3 microns in size. HEPA filters are a common component found in air purifiers which filter the air in order to clean it – there are other types of air purifier such as carbon filter, ionizers and even non-filter purifiers.

HEPA filters are also used in vacuum cleaners and in industries which require high air quality, such as aerospace, pharmaceuticals, nuclear power and the manufacturing of computer chips.

HEPA stands for High Efficiency Particulate Air. A HEPA air filter is made up of thousands of extremely fine fibres arranged into a matt to intercept both microscopic particles and larger ones. An air purifier will push air from the room through the filter to remove pollutant particles. By definition HEPA filters can trap close to 100% of the particles in the air that are 0.3 microns or smaller. (Bearing in mind that there are 10,000 microns in a centimetre, a particle 0.3 microns in diameter is really, really tiny.)

What are the benefits of a HEPA filter

When you invest in a HEPA filter you are buying technology that has been tested and approved against a standard. This ensures the quality and reliability of the filter to remove even the tiniest airborne particles. Air filtration is actually more important than many of us realise as indoor air contains many different irritants and pollutants. A correctly chosen HEPA filter can ensure these pollutants are removed efficiently, vastly improving the quality of air you breathe.

Why is it necessary to remove such small particles from the air?

Microscopic airborne particles are nearly impossible to see, but can be taken into the lungs and be irritating or damaging to your health, especially for anyone who suffers from allergies or asthma. Larger particles such as pollen, mould spores, dust and other allergens are usually filtered out of our systems in the nose or throat – causing all of those unpleasant symptoms that allergy suffers face. These larger particles are easily removed from the air by a HEPA filter.

Smaller particles, such as PM 10 particles, which are only 10 microns in diameter make it past our throat and into our lungs. Even smaller particles, like PM2.5 particles which are 2.5 microns in diameter, can make it right down into the alveoli in our lungs, posing a serious health risk. Most of these tiny particles are pollutants resulting from fossil fuels, traffic or chemicals. It was estimated that small particulate pollution cause around 370,000 premature deaths in Europe in 2005. Scary stuff really! We’ve written a whole other blog post on this subject here.

It turns out that a particle that is 0.3 microns wide is actually the hardest to filter out of air. So if a HEPA filter removes 99.97% of particles that are 0.3 microns in size, it is even more effective at removing PM10, PM2.5 and the larger allergens such as pollen.

Popular reasons for choosing a HEPA filter

  • New parents – A HEPA air filter will remove pollutants from the air making it safer for young children (and adults) to breathe.
  • Smokers – You need an air purifier with both a HEPA filter and a carbon filter inside. The first to remove smoke particles and the second to remove the fumes, gases and associated odour.
  • Pet owners – A purifier with a life time HEPA filter will remove allergy causing pet dander from the air. Look for a purifier with both a HEPA and carbon filter to remove allergens and odour.
  • Asthma Sufferers – A well chosen HEPA air purifier will removing common household allergens like mould spores, dust mite feces and household dust particles., allergy sufferers can enjoy refuge from the unpleasant symptoms.

When not to choose a HEPA filter

Yes, although HEPA filters are fantastic there are occasions where a non-filter air purifier would be better, for example if you want to kill airborne microbes and bacteria a model which works by incinerating particles, will destroy over  99.99% of micoorganisms. You see, as good a HEPA filters are, they cannot actually destroy anything. So things like mould spores, viruses and bacteria will continue to thrive unhindered unless they are actually destroyed. Something like an Airfree air purifier actually destroys these nasties without the need for replacement filters and are perfect for use in a bedroom or quiet area as they are usually completely silent too. Also, if you have an allergy to mould spores or dust mites, then again, the Airfree type of machine is far and away the best option for you. Destroying the mould spores, in turn kills off the dust mites, which in turn gets rid of the dust mite feces which is one of the most prolific airborne allergens in the home.

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