As good as HEPA air purifiers sound, they cannot remove gasses, chemicals, or odors. Consider that these are molecular level substances, and that the 0.3 micron holes are actually quite large compared to gas molecules. To compensate for this, most HepA air purifiers have some type of activated carbon based material that will absorb chemicals and odors. There are a number of different varieties of activated carbon that is included in most HEPA air filters. For example, the Air-O-Swiss unit has a thin mat in it to cancel out smells. In the Austin Air Purifier, there are pounds of activated carbon that do the same job. Regardless of the form, the carbon absorbs the gasses that would otherwise not be caught by HEPA air filters. These chemicals usually either cause unpleasant odors, or are possibly dangerous, harmful gasses.

Worth mentioning is the Blueair product line. The Blueair product line uses a different approach to HEPA. Not only do they provide a large surface area for air to pass through in their products, but they also have much larger openings in their filters, which are polymer based. This allows the Blueair to use a much smaller and less noisy fan and still achieve far more airflow. To compensate for this, these air purifiers use electrostatic brushes in the airflow just before the HEPA element. The result is that the pollution particles are charged electronically and end up getting stuck to the filter media, despite the larger passageway and increased air flow.

HEPA filter air purifiers are actually quite simple, in reality. A fan shoves airflow through a filter. As the same air passes back through the filter, it gets purer and purer. Therefore, the bigger the room, the bigger the product. Another approach, though, is more small air purifiers, which tend to work better. Think of a long, narrow room. If you put HEPA air purifiers at each end, the air only has to move half as far as if you were to put one larger purifier at one end, or even in the center. This results in cleaner air as not only does more air get treated, but the same air gets treated repeatedly, far more often than with just one of the HEPA air filters. Many times, the price is either comparable or better, and if a problem develops in one of your HEPA air filters, you only lose one and still have one small one in operation until you’re able to replace or repair the other.

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