A lot of people often end up thinking that air pollution is an occurrence which takes place outdoors but this is not true. In the home, there is a considerable amount of pollution.

In fact, considering the fact that we spend more time in the home, the pollution from inside the home is considered more dangerous to our health. In the home, we have different pollutants such as dust mites, dust, pollen and so on.

Indoor pollution is very capable of irritating your lungs and leading to a very serious allergic or asthmatic condition. A very good solution to all these pollutants would be an air purifier.

Using a vacuum cleaner may only simply rearrange or disturb these pollutants. The cleaner would clean some of the pollutants and send others into the air. The airborne pollutants are the most problematic. They can easily get into the respiratory system of man and cause a lot of problems.

An air purifier is very effective against the different pollutants which are found in the air in the home. It is a machine which is able to clean the air and filter the particles by making use of a HEPA filter.

What is HEPA (High Efficiency Particulate Air) Filter

The HEPA filter is powerful enough to trap 99.97% of 0.3-micron particles. HEPA stands for High Efficiency Particulate Air. The HEPA filter is a very effective tool used in air purifiers and other equipment but let’s take a closer look at how it works.

How HEPA filters work to trap dust and dirt

HEPA filter working

The air purifier works by pushing the air from the room across the HEPA filter. Basically, the simplest type of filter works just like a sieve. It has holes which are big enough to trap some particles and small enough for others to pass through.

Now, the HEPA filter is different because the filter isn’t just one filter. It can be said to be a very fine filter that was created by keeping several filters on top of one another. As the purifier sucks the air into the machine, a lot of particles get trapped in the purifier.

Hepa filter design

On taking a look at the design of a HEPA filter, you would find that the filter commonly has different outer filters working like a sieve to trap the very large particles such as dirt, dust, and hair. Beneath those filters, we have another network of a filter that is designed to trap the smaller particles which escaped the other filters.

This inner network of filters looks more like folded paper. It is very dense and is responsible for trapping these smaller particles. The filter is so dense that the particles simply smash directly into it and are prevented from going further. This means that as the air purifier sucks the air into the machine, the different particles are getting stuck in the HEPA filter.

The truth about HEPA filters is that they were designed for a completely different application. They were made to be used in the nuclear industry to help clean up the very dangerous particles flying around. A lot of us don’t have to deal with nuclear radiation but the filter can be useful in keeping our homes from overtaken by pollutants.

What are the different types of HEPA filters?

According to NIOSH(that is, US National Institute for Occupational Safety and Health), a true HEPA filter is one which is capable of trapping 99.97% of 0.3-micron air particles. This size is very small as a micron is one-millionth of a meter.

The simple truth about 0.3 microns is that they are the ones that are most likely to get through filters. Funny enough, smaller and larger particles easily get trapped but not the 0.3-micron particles. Keep in mind that the human hair measures about 50–150 microns in diameter; this means that the HEPA filter is trapping something which is about several hundred times thinner.

The HEPA filter is very important because it is basically cleaning at a very microscopic scale. The sooth that is expelled from diesel engines is often less than 10 microns (PM10) or less than 2.5 microns (PM 2.5). A true HEPA filter is much more powerful than any regular filter and it is capable of trapping mold spores, bacteria, and even certain viruses.

When talking about filters used in respiratory equipment, NIOSH is known to recognize nine grades which are dependent on three different levels of efficiency and three levels of resistance to filter degradation (N, R, and P). N means the filter is not resistant to oil; R means the filter is oil resistant while P means the filter is oil proof.

That means you may come across a filter labeled as N95 (this means it is 95 percent efficient at stopping particles and is not resistant to oil) or P100 (this means it is 99.97% efficient at trapping particles and is oil proof)

You may also come across HEPA filters which are classified using the letter A – E, depending on how well they capture particles and resist air flow.

The Type A filters are the least effective filters that meet the HEPA standard.

Type E is known to be the best type of HEPA filters which you would find. Type E filters are capable of dealing with chemical, radiological, or biological particles.

When it comes to air purifiers, you will commonly find three types of HEPA filters namely:

  • HEPA filter
  • True HEPA filter
  • Super HEPA filter.

Most effective air purifiers run on the true HEPA filter which is capable of trapping 99.97% of 0.3-micron air particles. This is powerful enough to stop most of the pollutants found in the home.

It doesn’t matter if you find the HEPA filter in an air purifier, mask, or even a vacuum cleaner. They are designed to serve the same purpose. They are designed to trap particles and make our environment much safer for human living.

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