The difference between a HEPA filter and other filters is that it is made of thin fibers of glass. The fibers are formed into a thick paper-like material that is pleated, with some HEPA air filtration systems having as much as 40 square feet of the folded filter material in the HEPA system. As particulates in pretreated air attempt to pass through the filter’s thick, folded surface they cannot; instead, they adhere to it.
There are three ways the HEPA filter stops particulates:
- First, particulates simply run into the fiber and stick
- Secondly, when particulates get within one diameter of the filter’s fiber, rather than passing through the fiber they are drawn to and get stuck on the fiber
- Third, as a very small particle (about 0.1 micron) moves through the filter it collides with other molecules (Brownian motion) and again gets caught in the fiber
Since pure HEPA air filters do not remove odors, chemicals or gasses, HEPA air purifiers have some level of activated carbon-based material to absorb odors and chemicals. Carbon absorbs gasses that will not be caught by the HEPA element. These chemicals are either harmful gasses or those that cause odors.
Because HEPA Air Filtration Systems combine HEPA filters with carbon-based materials, they stop mold spores, bacteria, viruses, pet dander and dust, and also help to eliminate harmful gasses and odors from your home. Thus, the air that leaves this type of air purifying system is cleansed and almost totally free from contaminants.
Incorporating this technology, the GeneralAire® AC500 HEPA Air Filtration
to watch a video demonstrating how to change your AC-500 HEPA Air Filters
System is 99.97% efficient at removing particles 0.30 microns from the air that passes through the HEPA filter.