What Is a HEPA Filter & How Does It Work?

The air quality in the United Kingdom is generally considered good, but the air quality has become a growing concern, especially as it can take a serious hit during bushfires and dust storms. It is estimated to cause forty thousand premature deaths each year, which is about 8.3% of deaths, while costing around £40 billion each year.

HEPA filters, short for “High-Efficiency Particulate Air” filters, are highly effective at capturing tiny particles compared to other filters. If you’re aiming to create a healthier home environment, particularly in areas prone to air pollution or for those dealing with allergies, understanding how these filters work will be helpful.

What Is a HEPA Filter?

A HEPA filter is a type of air filter that captures at least 99.97% of airborne particles as small as 0.3 microns (μm), including dust, pollen, mold, bacteria and other pollutants that could otherwise circulate in the air you breathe. The term "HEPA" stands for “High-Efficiency Particulate Air”, and these filters are widely used in household vacuum cleaners, industrial air filtration systems, and even hospitals.

To be classified as a HEPA filter, it must meet specific criteria, with Grade 1 filters capturing at least 99.97% of 0.3μm particles, and Grade 4 filters snatching an impressive 99.999% of particles as small as 0.12μm. To give you a better idea, 0.3μm is commonly used as the most penetrating particle size (MPPS) when measuring filtration efficiency, as it represents the size of particles most likely to pass through the filter, including airborne allergens and germs.

You may also come across the terms "True" or "Absolute" HEPA filters and HEPA-type filters – Simply put, True HEPA filters are heavily tested to meet strict industry standards for trapping 99.97% of 0.3μm particles; while HEPA-type filters do not meet the same high standards and are, therefore, less effective for serious air filtration tasks.

How Does a HEPA Filter Work?

A HEPA filter works by forcing air through a dense mat of fibres that trap tiny particles from recirculating back into the air. This process is highly effective for dust, pollen, pet dander and even microscopic pollutants like bacteria and viruses.

Mechanism

HEPA filters trap particles using a combination of three primary mechanisms: interception, impaction, and diffusion. As air passes through the filter, larger particles like dust and pollen are captured through interception, where they collide with and stick to the fibres. Smaller particles are trapped by impaction, where the inertia of these particles leads them to embed themselves directly into the fibres. The smallest particles, such as viruses, are captured by diffusion, a process where the particles move randomly and are eventually caught in the dense fibre mesh.

Particle Size

From large particles like pollen and dust mites, to microscopic particles like bacteria and viruses, HEPA filters are designed to capture them all. The size of the particles these filters can capture typically ranges from 0.3μm and larger, which covers most airborne pollutants. Hence, they are highly effective in reducing allergens and other contaminants in the air.

Efficiency

HEPA filters are known for their impressive efficiency to capture 99.97% of tiny particles. In practical terms, this means that nearly all unwanted particles – pollen, pet dander and even some bacteria, are removed from the air. This level of filtration is particularly beneficial in homes with pets, smokers or individuals with allergies.

In terms of application, their usage is not just limited to air purifiers; they can also be found in home appliances, automobiles, industrial HVAC systems and medical facilities. In homes, HEPA filters are commonly found in vacuum cleaners, just like DEEBOT X2 COMBO, which is equipped with a HEPA filtration system in the handheld vacuum to capture fine dust particles and allergens while cleaning the floor.

What Are the Benefits of a HEPA filter?

Using a HEPA filter can improve your living environment by capturing allergens, reducing airborne contaminants and minimising the need for other air purification methods.

Investing in a device with HEPA filter and you can enjoy these benefits.

● Enhanced Air Quality: When pair a home appliance like vacuum cleaners with HEPA filters, you can prevent fine dust and pet dander from being released back into the air during vacuuming. The fewer allergens floating around, the better overall air quality.

● Health Benefits: For those with respiratory conditions such as asthma or allergies, HEPA filters are incredibly beneficial. For instance, if you have a pet dog that tends to shed hair, a HEPA air purifier can effectively remove pet hair, dander and even odours from the air, thereby reducing your exposure to allergic triggers that can cause symptoms.

● Multi-use: HEPA filters aren’t just for air purifiers. They are also used in vacuum cleaners, air-conditioners, HVAC systems in laboratories and factories, as well as in medical facilities and hospitals where clean environments are vital.

● Environmental Health: By capturing tiny particles before they can spread, HEPA filters make sure fewer pollutants are recirculated into the air. As a result, air quality and overall environmental health is improved.

● Convenience: HEPA filters are generally easy to maintain. To keep them operating at their best, detach and clean them regularly to avoid clogging issues. These filters can be reused for a period of time and should be replaced when necessary – they are conveniently available online or at local stores, so it’s a good idea to keep a few at home as backup.

● Cost Savings: To keep your home clean and healthy, regular vacuuming, dusting, and cleaning are required, but they can be time-consuming. A HEPA filter can help you save both time and money by effectively removing dust and allergens, hence reducing the need for extra air purification methods and lowering overall cleaning costs in the long run.

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