The problem with the air pollutants is that we don’t know what effect they may have on our health in the long term.

India is home to half of the most polluted cities in the world.

According to WHO, most of the premature deaths are a result of household air pollution.

It is shocking to know that the air pollution level in the homes can be 10 times more harmful than outdoor pollution.

With the rate of increase in Air Pollution, Air Purification has become a dominant force worldwide.

Air Purifiers are meant to purify the indoor air of the harmful pollutants.

We shall discuss the various type of filters used in Air Purifiers.

Pollutants Which Air Purifier Targets

The main task of the Air Purifiers is to clean the indoor air of the pollutants which can cause respiratory problems.

Below is a list of various pollutants which an Air Purifier targets inside the home:

  • Dust
  • Mites
  • Mold
  • Soot
  • Germs
  • Pet Dander
  • Bacteria
  • Viruses
  • Fungi
  • Pollens
  • Allergens
  • Smoke

Filters Used in Air Purifiers

1. Active Air Purifiers

Active Air Purifiers purify the air through ionisation. They give ozone as a side product.

2. Passive Air Purifiers

These purifiers depend on air filters to remove dust and dirt from the air. They can remove the dust particles permanently.

What Are the Types Of Air Filters?

1. HEPA Filter

HEPA stands for High-Efficiency Particulate Air Filter.

HEPA Filters can remove 99.97% of the airborne particles.

Even the tiniest 0.3 micrometres sized particles cannot escape from these filters.

It weeds out debris, bacteria and also soaks out smoke and odour.

The best thing about HEPA filters is that the impurities collected cannot find their way back into the air.

Doctors recommend these filters to the patients suffering from allergies.

2. Carbon Filter

There is plenty of chemicals in furniture and paints, pet odour and moisture make things more uncomfortable.

Activated Carbon Filters are used to remove a plethora impurities like:

  • Smoke
  • Odour
  • Pesticides
  • Herbicides
  • VOCs
  • Chlorine
  • Sediments

Drawback: Even the best Ventilation System cannot remove these impurities, Carbon filters are not that useful in removing tiny dust particles and organisms.

3. Prefilter

We can call it a double filter in an Air Purifier.

Prefilter works as a wall to stop large particles from entering the main filter.

It stops the hair furs, debris, dust and pollen which increases the capacity of the air filter.

In other words, it decreases the load on the internal filters.

As a result, the lifespan of the main filter increases.

You can wash and reuse these filters.

4. Catechin Filter

Catechin filter got its name from a natural anti-oxidant present in green tea.

These filters destroy virus and bacteria.

They also remove pet odour and smoke.

It improves overall health.

They are very durable. With proper maintenance and routine cleaning, they can serve you for a long time.

5. Vitamin C Filter

The name itself defines everything related to these filters.

It is a filtration-cum-therapy.

Vitamin C Filters fill the air with Vitamin C which makes the skin soft, gentle and reduces stress. These filters also fight with free radicals which cause aging and makes the skin look dull.

6. Anti-Bacterial Filter

These filters kill germ and bacteria present in the air.

This filter is a defence against microbes spread across the room.

This filter either comes in one piece or along with HEPA filters.

These filters can be easily cleaned using vacuum cleaners or a usual hand wash.

7. Anti-VOC Filter

VOC stands for Volatile Organic Compounds. These compounds contain carbon.

Pesticides, paints, furniture, etc. may emit these compounds in your rooms.

It might give you a headache, watery eyes, nausea or a runny nose.

They can have short-term, as well as, long-term effects on health.

An Anti-VOC filter removes toxic VOCs, other impurities and hazardous gases from the air.

8. PM 2.5 Filter

It removes PM (Particulate Matter) less than 2.5 micrometres in size.

PM 2.5 can cause major health problems such as :

  • Eye and Nose Irritation
  • Throat and Lung Irritation
  • Coughing and Sneezing
  • Chronic Bronchitis

PM 2.5 filters are designed to trap these micro particles.

It consists of a PTFE (polytetrafluoroethylene) membrane.

It is a soft and elastic material with a pore size of 2.0 microns.

It means that these filters can trap 2.0 micrometres sized particles.

9. UV Light Filter

These filters use UV light to destroy bacteria, viruses, molds and yeasts.

These filters can also remove smoke and bad odour.

This filter is ideal for someone who gets sick repeatedly.

It is used in hospitals to prevent infections.

Drawback: It cannot remove solid particles, dust, allergens from the air.

10. Photocatalytic Filter

Nowadays, many ACs and air purifiers come with photocatalytic filters.

The catalyst used in these filters which that cleans the air is Titanium dioxide.

When UV light falls on this catalyst, electrons are released at its surface. These electrons react with the water molecules in the air and form hydroxyl (OH) radicals.

These hydroxyl radicals attack the pollutants. They make the pollutants neutral and make them non-toxic.

It is an example of PCO (Photocatalytic Oxidation).

Drawback: Its only drawback is that it produces a small amount of Ozone (O3), that itself is a pollutant. So, it’s better to avoid purchasing PCO technologies as it can trigger Asthma problems.

How To Choose a Right Air Purifier For Your Home?

A filter is the most important part of Air Purifier. Different purifiers use different filtration technologies.

Here are some of the points to keep in mind before choosing an Air Purifier:

1. Buy an Air Purifier With A Prefilter

These are basic filters which remove pet hair, dust, microbes from the air. It increases the lifespan of the air purifier.

Make sure to clean these filters regularly.

2. Room Size

Nowadays, a number of purifiers are available in the market ranging from compact to heavy sizes.

You should opt for the one which can purify the air in a slightly larger space than the size of the room.

3. ACH

ACH stands for Air Changes Per Hour.

ACH value tells how many times a purifier can exchange the air within a room with clean and fresh air in an hour.

It is expressed in multiple of ‘x’ like, 3x, 4x, 6x, etc.

Higher the number, more efficient is the purifier.


CADR stands for Clean Air Delivery Rate.

It gives you an idea about how large room can an air purifier handle.

CADR measures three types of impurities:

  • Dust
  • Tobacco Smoke
  • Pollen

CADR ratings can lie anywhere between 10-450. This rating is a set of three numbers separated by a slash.

For example, in a CADR rating of 200/220/190, 200 refers to dust, 220 is for tobacco smoke, and 190 is for pollen.

Higher the number, better is the air purifier.


Every air filter is meant to improve the quality of air.

HEPA purifier is a good choice as it removes tiniest of the impurities present in the air.

Try to avoid such air filters which produce ozone as a side-product.

You can buy the best air purifier as per your need and budget on the online shopping sites.