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.

The amount of activated carbon, as well as the type and other things with which it is blended, as well as how it is used in HEPA air purifiers depends largely on the model and brand of the HEPA air purifiers.

For example, the Austin Air HM400 uses 18 pounds (!) of granular activated carbon impregnated with zeolite. The zeolite enhances the chemical absorption qualities fo the activated carbon.

The Austin Air HM400 SuperBlend also contains 18 pounds of granular activated carbon, but it is impregnated not only with zeolite, but also potassium. This makes it effective at removing formaldehyde.

The Blueair 501 and 601 systems contain three integrated HEPA air filters. Unlike Austin Air, Blueair does not specify the weight of the carbon included. The optional SmokeStop filters have a lot more activated carbon than the standard filters that the unit comes with, though.

The V-5 Cell filter in the HealthPro Plus by IQAir has a five filtration chamber that includes a blend of activated carbon, as well as impregnated active alumina. This provides for enhanced absorption. Like Blueair, IQAir does not tell us the weight of the activated carbon that is in their HEPA air purifiers.

In most cases, pollens and pet dander are the main things that people are concerned about when buying HEPA air purifiers. Odor and chemical absorption are often less important, if they’re important to the consumer at all. Some, though, may be looking for a high degree of both. for those people it is best to look for high caliber HEPA air purifiers that offer outstanding odor, chemical, and particle removal. Volatile organic compounds, known as VOC’s, such as ozone, pets, tobacco, smog, and even cooking can be irritating or downright unhealthy for anyone, not just asthmatics and those with bad allergies.