What is a HEPA Air Purifier? Working, Benefits & Limitations!

In Brief: What is a HEPA Air Purifier

HEPA (High Efficiency Particulate Air) purifier uses a multi-layer mechanical filtration technique to trap the microscopic impurities suspending in the air. It can trap particles of different sizes ranging from 5µm to less than 0.1µm with an efficiency of 99.97%. Its purpose is to filter the contaminants in the air and create a pollution-free environment.

Different types of air purifying technologies are available in today’s market. Each purifier has its own merits and demerits and is suited for specific situations.

If you are searching for a purifier with high efficiency and better filtering capacity, HEPA Air Purifier is the best choice. We will now discuss about HEPA air purifier in detail.

This article will give you an idea of the HEPA purifier and help you decide on whether you should choose a HEPA air purifier to solve the problem.

What is HEPA air purifier technology

HEPA purifier technology uses mechanical filters to filter both particles of larger size like dust, mold, pollen, etc and microscopically small airborne particles that are of 0.3 µm in size with an efficiency of 99.97%.

The HEPA filters are made up of either fiberglass or Plastic, and the sheets are pleated to increase the overall surface area.

How HEPS filter Works?

HEPA air filters remove the contaminants in the air using the multi-layer filtration technique. The air is forced through the fine mesh of filters to trap the air pollutants.

Now let us briefly discuss the filtration technique used in the HEPA air purifiers.

The HEPA air purifiers have five filtering mechanisms, each for separating particles of different sizes.


Sieving is the most commonly used filtering mechanism.

Particles that are too large to fit between the fiber spaces are trapped and filtered at this layer. Particles of size 5µm and above are filtered.

Inertial Impaction

In this layer, larger particles of size ranging between 1µm and 5µm that escaped the sieve layer are filtered using an impaction mechanism.

Larger particles suspended in the flow stream have more mass and are incapable of changing its direction when it enters the fiber space because of inertia.

Thus, they move in a straight line and get trapped by the fiber in this layer.


Mid-sized particles of range 0.1 µm to 1 µm, are intercepted as they traverse through the air stream and get trapped in this layer when they come into direct contact with the fiber.

These particles must be of one particle radius of the filter to get trapped.


Particles that are smaller than 0.1 µm are trapped in this layer by the Brownian diffusion mechanism.

The small particles diffused in the airflow will collide with other gas molecules and create a Brownian motion.

The smaller the particle size, greater will be the random motion, thus increasing the probability of the particles getting trapped by the fiber.

Electrostatic filtration

It is the last filtration layer. It is not a dominant method but still plays a role in the filtration process.

As the air flows through the filters, it will develop a negative charge around it. These negatively charged particles are attracted to the positively charged fiber and get trapped by them.

I hope you would have gotten a clear image of the different filtering techniques used in the HEPA air purifier.

Benefits of HEPA air purifier technology

Now let us discuss the benefits of HEPA Air purifier.

High Efficiency – HEPA purifiers have high efficiency of 99.97% and filter impurities of different particle sizes at ease.

Improve Air Quality – HEPA purifiers are capable of filtering most of the airborne contaminants and in-turn improve the indoor air quality.

Filters Allergens – HEPA filters can trap almost all the airborne allergens like pollen, dust, spores, etc and aids people with respiratory ailments like asthma, allergy, etc to breathe fresh air.

It helps pet lovers with asthmatic problems to live a happy life with their pets by trapping the pet hair and pet dandruff.

Limitations HEPA air purifier technology

Benefits and Limitations go hand in hand. Now let us see some of the limitations of the HEPA air purifier.

Gaseous impurities – HEPA filters are incapable of filtering gaseous contaminants like fumes, gases, and odors.

For example, HEPA filter can’t purify VOC (Volatile Organic Compound), an airborne chemical released from building materials, cleaning products, and beauty products. VOC is said to be carcinogenic in nature.

Microbes – HEPA filters are not capable of killing any microbes or spores.

Microbes like bacteria that get trapped in the filter will release an endotoxin in the air when it dies. This toxin can cause inflammation in the respiratory tract and atopic reactions to the people who inhale this air.

The spores that get trapped on the filters will grow feeding on the other particulates that get trapped the filter as its ingredients and in-turn reduces the filtering efficiency.

Where HEPA air purifier technology can benefit

Now let us discuss how the HEPA purifiers benefit us in our day-to-day life.


HEPA purifiers are commonly used at home by parents to protect their children from allergens or respiratory diseases causing agents.

It also helps old-people or people with asthmatic problems breathe fresh and pure air, thus creating a cozy environment to live-in.


HEPA filters are used in the office or company to remove the toner dust. They are also used in industries as industrial vacuum cleaners to remove asbestos that is hazardous to humans.

It is also used to purify the cigarette smoke in the smoking area of restaurants, bars, etc.

Pet shops

HEPA purifiers are used in pet shops to filter the pet’s hair and dandruff floating in the air. It creates a good atmosphere for both the pets and customers.


HEPA purifiers are used in hospitals to purify the air and prevent the spread of airborne microbes. These filters also purify the air in the surgical smoke evacuation, surgical respiratory system, biological safety cabinets, etc.


Thus, HEPA purifier is used to filter contaminants of different sizes from large dust particle to small airborne microscopic organisms.

It is also known for its high efficiency and cost-effectiveness.

From the above article, you must have a clear understanding of the HEPA purifier, its pros and cons, and its application in different fields.

In case of further information please type in the comment box below or reach us through email

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