What is an Air Purifier? How Does Air Purifier Work?

How Does an Air Purifier Work

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Air is not the only thing we take for granted but one which carries a huge impact on health if inhaled polluted. We all are vulnerable if exposed to the polluted air, but the consequences depend on various factors such as age, immunity, health etc. No one is certain how much-polluted air their body can withstand without incurring health problems?

It is quite possible to purify the indoor air by removing air pollutants, artificially. Air purifier does this job and, to learn more, let us discuss that how does it work? How different filters play their role? And where an air purifier would cease to work?

What is an Air Purifier?

An air purifier s a device which is designed to capture air pollutants. The device processes the air and strips it of pollutants, effectively.

An air purifier carries huge health benefits as it removes dangerous contaminants, allergens, foul smell, bacteria, and, therefore, is an intelligent investment.

How Does an Air Purifier Work?

What is an Air Purifier

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Regardless of air purifying techniques, fan and filtration system are the two chief components of the air purifier. There are different types of air purifiers in the market, but their basic working principle is the same.

Let us go in detail of what does a fan do and how the filtration system works.  

1. What does a fan do?  

Air purifiers have fans inside which perform the responsibility of sucking in the dirty air along with air pollutants into the device and to blow it out once all the pollutants are captured.

Users may vary the speed depending on the type of model and it goes in your best interest to run it on faster speed, but you have to bear the noise for that.

2. Filtration system

The air pulled inside by the fans are subjected to travel through various filters where all the cleaning operation happens. We can say that filters play a major role in all the magic air purifier does. Depending on nature, there are various types of filter which purify the air in their specific way.

Air purifier device could be assembled with a different set of filters to perform different operations. Typically, once the air is sucked inside passes through all the filters to come out clean.

Based on the role of filters, below is how a typical air purifier works.

The Pre-Filter 

The pre-filter is the first line of defense when exposed to pollutants. Air enters passes through these filters and is stripped of the dust particles. They do the major work of removing big particles and molds to ease off things for the second line of defense.

HEPA Filter

HEPA stands for High-efficiency Particulate Arresting and is the best-known filter in the market. HEPA has taken the purifier to the appreciating level and made it possible to 99.97% purify the air.

These filters are made of tightly woven minuscule glass fiber which vary in thickness depending on the purpose. This highly dense fiber paper seizes airborne toxic contaminants (like dust, mold, pollen and even animal hair). This is extremely beneficial and passing air through it repeatedly cleans it more.

Ideally, at the end of this stage, there shall be no more particles left in the air.

Activated Carbon Air Filter

There is a common myth about the air purifiers that they don’t work for gases and VOCs (Volatile Organic Compounds). However, they hold remedy for this too and this is where activated carbon air filters come in.

Carbon is injected with hot air, carbon dioxide, or steam to make it activated which enhances its ability of adsorption. This bed of activated carbon is used in these filters to trap gas molecules.   

The phenomena are called adsorption where molecules are stick outside the surface and are not absorbed inside the structure. When the carbon filter becomes saturated, it does not perform as effectively. Therefore, it is a common practice to replace it when it shows such symptoms.

UV Light Air Filter

UV Light Air Filter works best for the pollutants (mostly germs and viruses). The UV light is not released into the room but is trapped inside the purifier. It is harmless for a human, anyway.

Once the air has passed through all filters then it is exposed to the UV light in a small internal chamber inside the device. Virus and bacteria vary in size and capturing them alive may go against our chief purpose; to purify the air. Therefore, this filter sterilizes the virus or germs and prevents them from spreading by deactivating them.

What Won’t Air Purifier Work for?

Though we have discussed in detail what they can do, it is all the same important to know what they cannot. 

  • One limitation is that they can only remove the suspended particles or molecules in the air but can’t help themselves against the settled dust on the furniture or the floor.
  • Last but not the least, when filters are used more than their capacity, they remain good for nothing. Therefore, you are required to replace filters after every 3-6 months depending on your usage and filter type if you want to get the best results from your device.


According to WHO stats, the air quality is falling every passing year around us. The invisibility of particles may make us complacent for a while but we cannot remain oblivious to the reality for a long enough. In this circumstance, air purifiers extend good services to us by purifying the indoor air. They are good enough to clean our air to near perfection.