What’s A Pre-Filter And Why Is It Important For An Air Purifier?

An air purifier is an essential equipment in your home or office. It’s particularly important if you live or work in industrial zones or dusty environments where the ambient air is perpetually polluted.  

The most useful internal component of air purifiers is the filters. These filters are classified into different categories depending on their efficacy.  

This article looks at pre-filters and the role they play in air purifiers. 

Introducing Pre-filters 

 

A pre-filter is an air filter that removes larger particles, such as dirt, dust, and hair.  

A typical air filtration process begins with pre-filters. Other filters within an air purifier remove any particle that cannot be eliminated at this stage.  

Since pre-filters are the first stage in air filtration, these components usually comprise the outermost layers of an air purifier’s filtration unit. That means they also protect the unit’s internal components from getting clogged up with debris.  

One of the best things about pre-filters is that there are different options. These include replacement carbon pre-filters, which are by far the most common. The type of pre-filter built into your air purifier depends on the machine’s model and intended efficiency. More on that later on. 

Uses of Pre-filters 

 

As already stated, the primary role of pre-filters is to sift out larger particles in the ambient environment. Trapping these macro particles prevents them from contacting your respiratory system.  

Dust, dirt, and hair can all irritate your lungs if inhaled. Depending on the chemicals they carry, inhaling such compounds can predispose you to chronic respiratory problems.  

The role of pre-filters and their outer location within an air purifier’s filtration system also allows them to protect the inner, most fragile filters.  

Pre-filters protect the innermost filters by preventing them from getting clogged with macro particles. This improves their efficiency at trapping the microscopic pollutants.  

 

Where Are Pre-filters Used? 
 

Pre-filters are part and parcel of any air purifier. You’ll find them in air purifying equipment installed in residential and commercial properties.  

Pre-filters are also found in air purifiers used in industrial centers and other public areas, such as commuter zones. 

How Do Pre-filters Work? 

 

To understand the mechanism of pre-filters, we’ll need to back up a bit and familiarize ourselves with how HEPA filters work.  

HEPA filters are made from either fiberglass or plastic. The filters comprise interlaced fibers, each with a diameter of less than one micron. These fibers are twisted and wound into a complex maze. 

 The diameter size and the structural arrangement of the fibers in a HEPA filter allow it to trap minute pollutants.  

Now, a pre-filter follows nearly the same model. The difference is that the fibrous layers in pre-filters are considerably larger than those in HEPA filters.  

Comparatively, pre-filters trap pollutants with a diameter of around 2 microns or larger. These include dust, dirt, human hair, pet fur, and pollen.  

 

What Are Pre-filters Made From? 

 

Pre-filters can be made from several materials. The most common ones include; 

1. Fabric

 

There’s a variety of fabric materials that can be used in making pre-filters. However, most manufacturers prefer polyester.  

Polyester fibers are remarkably effective at trapping macro chemicals. They’re also affordable and easy to clean, making them especially preferable for pre-filters in residential air purifiers. 

2. Fiberglass

Fiberglass stands out for its durability and high efficiency. Pre-filters made from this material can also withstand high temperatures and be moisture-resistant.  

Due to their ability to withstand the elements, fiberglass pre-filters are best suited for air purifiers in commercial, industrial, and public places.  

3. Polypropylene

 

Polypropylene is another common pre-filter material. It’s most beloved for its lightweight, affordability, and resistance to chemical erosion.  

Pre-filters designed from polypropylene are also quite reliable. Such filters can effectively clean the ambient air of pollen and fibers.  

4. Steel Mesh

Steel mesh pre-filters are made from a network of interwoven metal wires. Pre-filters are moderately effective at capturing larger particles, including debris and insects.  

Steel-made pre-filters are also highly durable. However, they tend to be considerably heavy. 

Types of Pre-filters 
 

There are two main types of pre-filters, namely mesh and carbon. Mesh pre-filters are designed to capture solid pollutants, whereas carbon filters capture both solid and gaseous particles.  

Mesh pre-filters work like a sieve. They comprise tiny spores of netting through which air can freely pass. As air flows through the netting, larger particles get trapped on the outside.  

Carbon pre-filters are more advanced. These filters comprise activated carbon material in various forms - powdered, granular, or honeycomb. As air flows through activated carbon pre-filters, larger particles, and gaseous pollutants remain on the outside.  

Some gaseous pollutants trapped by carbon pre-filters include volatile organic compounds (VOCs) and chemical vapors.  

Some activated carbon pre-filters will also trap odor molecules. That makes them all the more efficient in maintaining indoor air quality.  

Various aspects determine the type of pre-filter used in an air purifier. Most notably, the other filters in the equipment’s internal filtration system.  

 

Final Word 

 

Pre-filters play a crucial role in keeping ambient air fresh while protecting the internal components of an air purifier’s filtration system, and there’s plenty of research to back that up.  

It’s more exciting to know that there are different types of pre-filters. But as with any equipment, remember that pre-filters' efficiency comes down to regular cleaning and maintenance.