As many as 2000 years ago, human beings used activated carbon to remove impurities from water. Even then, its exceptional absorption qualities were known. However, it was not until the early 1900s that activated carbon was produced in powder form that could be sold commercially. At that time, it was used to purify water and to remove the color from sugar. As World War I progressed, it was discovered that activated carbon could be used in gas masks to protect soldiers, in addition to cleaning wartime water and in the manufacturing of air purifiers. It was during this period that granular activated carbon was developed.
You may find yourself asking why activated carbon is called "activated" and whether there is non-activated carbon, as well. The heat used in the process of changing carbon to an "activated" state drives out impurities; there are places for your air impurities to reside when it is used in an air purifier. After activated carbon has been used, it can actually be reactivated by heating it again. However, the reactivation process is impractical and dangerous. Non-activated carbon is soot or charcoal.
Activated carbon is described in a variety of ways, but generally the range includes amorphous carbon-based materials that exhibit a high degree of porosity and an extended surface area. This simply means that it has excellent absorbent characteristics that make it very useful for a wide variety of filtration processes, including air and water.
In room air purifiers, the activated carbon is often combined with other minerals, like zeolite. Zeolite can absorb ions and molecules and thus act as a filter for odor control, toxin removal, and as a chemical sieve. In some air purifiers, the carbon may be impregnated with potassium iodide or blended with active alumina to increase absorption qualities. These home air purifiers are particularly helpful to people with Multiple Chemical Sensitivity (MCS), because they absorb formaldehyde, a compound found in carpet, wood paneling, and furniture upholstery. Perfumes and chemicals in household cleaning items are also removed, making the environment much more breathable for all, especially asthma sufferers, babies, children, and the elderly.
The type and amount of activated carbon and how it is used in home air purifiers depends on the brand and model. Here are the highlights:
The Alen A350 air purifier features HEPA (High Efficiency Particulate Air) style filtration, combining three layers of filter technology to purify and freshen the air in your home. In the final stage, clean air passes through a layer of Alen's Activated Carbon, reducing odors and chemicals commonly found in the air from cleaning products, smoke, cooking, pets, and other household materials.
The BlueAir 603 air purifier contains three integrated HEPA/carbon filters. Though, Blueair does not publish a weight for the carbon included, the optional SmokeStop filters have substantially more activated carbon than the standard filters that come with the unit.
The Austin Air Healthmate Plus air purifier contains 18 pounds of granular activated carbon impregnated with a blend of zeolite and potassium, making it effective at removing formaldehyde and other harmful chemicals.
VOCs (volatile organic compounds), smog, ozone, fumes from cooking, pet dander, and tobacco can cause irritation for allergenics and asthmatics. Particulates, such as pollens or pet dander, are the main irritants for many households. For those who need a comprehensive air purifier solution, higher caliber room air purifiers that offer outstanding particle, odor, and chemical removal are ideal.