Activated carbon in HEPA air purifiers may seem strange to you, unless you own a water purification system which uses carbon or are an aquarium hobbyist. Even so, you may not understand exactly what it is activated carbon does.

For most people, though, the first time they encounter activated carbon will be in choosing HEPA air purifiers. Most customer begin their search for air purifiers due to asthma or allergies. As they learn more about HEPA air purifiers, though, they’ll learn that many of their respiratory problems come from chemicals and odors in the room. Therefore, most quality HEPA air purifiers are designed to address the chemicals and odors as well as the allergens themselves.

Believe it or not, humans were using activated carbon to purify water as many as two centuries ago. Even back then, we knew of activated carbon’s exceptional absorption qualities. It was not until the early 1900’s, though, that the stuff was produced in a form that could be sold commercially. Produced commercially, activated carbon was sold as powder. Back then, it was used only to remove smell or taste from water and to remove the color from sugar. As World War I got into full swing, we discovered that activated carbon could be used in gas masks to protect soldiers from chemical agents in the air. Not only that, but it was used for war time water and air purifying. At this point, instead of being used in powder for, it was used in a granular form. This was the beginning of activated carbon being used in many ways.

You’re probably wondering why we’re referring to this carbon as “activated.” Is there such a thing as non-activated carbon? Well, the heat used in “activating” the carbon is what drives out the impurities in the carbon itself. This leaves a place for the impurities in whatever it is the carbon is cleaning to reside. So activating carbon is kind of like emptying a sponge, only with head instead of pressure. After activated carbon becomes full, it can actually be reactivated by re-heating it. This is, however, not a good idea, and is considered dangerous and impractical. Non-activated carbon is basically charcoal or soot.

There are a variety of types of activated carbon, and it is described in a variety of ways, but generally activated carbon includes a wide range of amorphous carbon-based materials. These materials have a high degree of porosity (lots of holes) and a relatively large surface area. Basically, this means it has excellent absorbent characteristics. These absorbant characteristics are why activated carbon works so well filtering air and water both.

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