Air Purification 101: What do Different Types of Filters do?

air purification

An air purifier which uses a HEPA filter.

If you are someone who is completely new to the world of using air purifiers to naturally improve your health and remove impurities from the air, it can be a bit daunting to figure out the differences between the different types of filters and purifiers. What is the difference between carbon and HEPA filtration? Do you need a medical grade filtration system, or something to keep the smell of tobacco smoke from settling into your house? These questions can be difficult to answer, and so we at US Air Purifiers have decided to put together a beginner’s guide to air purification. We’ll start with this post, which will cover the most basic question: what do different kinds of air purifier filters do?



By far the most common type of filter in air purifiers, HEPA stands for High Efficiency Particulate Arrestance. These filters are ideal for particulate matter, such as pollen, mold or dust. As such, they are the general favorite of those who suffer from allergies or asthma. These filters are made from multiple layers of filter material, and are required by law to filter at least 99.97% of particles greater than 3 microns in diameter.



Carbon, besides being quite lovely when compressed into diamond or useful in pencils, is an excellent filtration material. This is because of the porous nature of granular carbon. Having a large surface area with many pores, a grain or carbon can absorb contaminants directly from the air during the filtration process, making it ideal for smoke and gases that HEPA filters cannot catch, being sized at the molecular level. Carbon can also be treated with various reactive chemicals that will make this type of filtration even more effective.


  TiO2 Filtration

Those familiar with either chemistry or painting may notice that the chemical formula TiO2 (titanium dioxide) is the same chemical compound used as a pigment in most white paints. However, it has an entirely different usage when it comes to air purification. TiO2 filters are used in many hospital grade filtration systems, such as the one in the Field Controls TRIO unit, as one of many filters. This filter technology is excellent for germs, smoke and unpleasant odors.



Usually used in conjunction with one or more other types of filtration, ionizers are devices that electrically charge molecules in the air to form ions. This causes particles in the air to attach to a grounded electrode, and also kills bacteria and viruses. Some people think that ionizers inherently produce large amounts of ozone. However, this is not true. Some, such as those used in various Bliueair models, cause no net increase in ozone in the air that is filtered.



Air purification isn’t always quite as simple as it seems. There are many different types of air purifiers that operate in many different ways. However, by understanding the uses of the various types of filtration systems, you can start to decide what will match your needs.

If you need more help picking out the right air purifier, you can email us at: