Why Is There Activated Carbon In HEPA Air Purifiers?

Unless you're an aquarium hobbyist or own a water purification system that uses carbon, the idea of activated carbon in HEPA air purifiers probably seems strange to you. Even if the concept isn't completely foreign, most still don't know exactly what activated carbon actually does.

How Is Active Carbon Used In HEPA Air Purifiers?

The first time most people encounter activated carbon is in choosing HEPA air purifiers. When most customers begin searching for air purifiers, generally due to allergies or asthma, they really have no idea how they work. As they are further educated about HEPA air purifiers, however, they will learn that odors and chemicals are the cause of the vast majority of their respiratory problems. Most quality HEPA air purifiers are designed to take care of not only allergens, but also the odors and chemicals in the air as well.

Was Active Carbon Used Before HEPA Air Purifiers?

Activated carbon has actually been around for quite a while, and though it sounds quite scientific, our ancestors have made good use of it for at least the last two centuries. Back then, they already knew of activated carbon's extraordinary absorption qualities. In the early 1900's, the stuff was produced and sold commercially in the form of a powder. At the time it was only used to remove color from sugar or taste or smell from water. Although we didn't know it at the time, that was barely the tip of what this stuff is capable of. In World War I, the military discovered that they could use activated carbon in gas masks, filtering chemical agents from the air for the soldiers. The soldiers also used it for water purification, just like their ancestors. By this point, it was also available commercially as a granular form instead of just powder, which was when it began finding uses in even more situations.

What Activated Means

So, what is "activated" carbon, and is there such a thing as non-activated carbon? The heat used in "activating" the carbon drives the impurities out of the carbon itself, leaving places for the impurities of the water or air or whatever it is the carbon is filtering to reside. In a way, carbon can act sort of like a sponge, only instead of squeezing out its contents, one heats it out. Once the activated carbon is full, it can be reactivated by re-heating it, though this is considered to be impractical and dangerous. Non-activated carbon would basically be carbon that has stuff in it already, such as soot or charcoal.

Is All Activated Carbon The Same?

Basically, yes. Though there are different types of activated carbon, and it's often described in various ways, all activated carbon is nothing more than amorphous carbon-based materials. These materials all have many holes, also known as a high degree of porosity, which cover a relatively large surface area. This is what gives the material such awesome absorbent quality, enabling it to work so extremely well in filtering both air and water.

Harry writes articles about his HEPA air purifier, and HEPA air purifiers in general.