Types of Air Filters
There are basically two types of Air Filters:
- Arrestors, which physically trap pollutants.
- Non-Arrestors, which alter the pollutants characteristics without capturing them.
| Arrestors |
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Mechanical Air Filters |
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Most mechanical air filters use a woven material to capture particles as the try to pass thru. Because they accumulate trapped particles,
Mechanical air filters will require maintenance. Some are washable, otherwise dirty filters are discarded and replaced by new ones. As dirt accumulates
in the filter, the filter's effectiveness will be reduced by restricted air flow; so maintenance is very important. Air filters with the ability to trap 99.97%
of particles larger than .3 microns in size are called HEPA or High Efficiency Particle Arrestor.
Absorbents such as charcoal can also be used to Arrest pollutants. Porous materials like charcoal act like sponges to absorb odors and gaseous
pollutants. Because the pollutants accumulate within the charcoal, these too must be regularly maintained. |
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Electrostatic or Electronic Air Filter |
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An Electrostatic or Electronic Air Filter places a charge on particles as they pass by an electrical grid. This gives them a charge which makes them "sticky". The "sticky" particles then pass by some oppositely charged collector plates. Since they are "sticky" with the opposite charge, the particles cling to the plates. Because the plates accumulate particles, they will eventually become covered and need washing, so an electrostatic air filter's ability declines with use and requires maintenance. The electrical charge may also produce ozone. |
| Non-Arrestors |
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Ionic Air Filters |
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Ionic Air Filters generate an electrical charge. The pollutants in the air become "sticky" and cling to the walls and ceiling and furniture in the room. Because the pollutants are "sticky" they may also cling to the inside of your lungs when you inhale them. Ionic Air Filters may also produce Ozone as a byproduct. Ozone may be considered an irritant. |
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Ozone Air Filters |
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Ozone Air Filters manufacturer a form of oxygen that combines with pollutants and changes their chemical make up. Ozone Air Filters are mostly
used for smoke and odor removal . Again, ozone is considered an irritant and may be harmful in large doses. |
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Ultra-violet Air Filters |
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Ultra-violet Air Filters are used to kill bacteria, molds, and viruses. Ultra violet light is harmful to the eyes, so the air must be drawn into the air filter where the pollutants are exposed to the deadly light. The speed of the air and the light intensity are critical to it's success. This type of air filter does not remove particles, but can be combined with a mechanical filtering device to do so. Ozone may be a byproduct of this type of Air Filter. |
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