| The Environmental Protection Agency has | | | | These filters are used as the primary filtration |
| determined that almost 90% of the people spend | | | | systems for electronic clean room assembly, |
| their time indoors. This means that indoor air | | | | isolation wards, surgical theaters, bioengineering |
| quality is much more important than outdoor air | | | | units, pharmaceutical processing units, and other |
| quality for most people. | | | | places where the maximum removal of |
| HEPA (High Efficiency Particulate Air) filters are | | | | sub-micron particulate is required. They are also |
| recommended by allergists and medical | | | | used in portable units to supplement a building's |
| professionals for the removal of all dust particles | | | | ventilation system by providing disinfected air. |
| in the size range of droplet nuclei from the air. | | | | Doctors are advising the usage of HEPA filters in |
| The HEPA filter, a mechanical filter, was | | | | heating/cooling systems for the prevention and |
| developed by the Atomic Energy Commission of | | | | treatment of Tuberculosis. HEPA air cleaners, |
| U.S.A. during World War II to prevent radioactive | | | | vacuum cleaners and air filters are essential by |
| particles from escaping from plants and | | | | law to be used in all equipment for asbestos, lead, |
| laboratories. Those initial HEPA air filters were | | | | toxic chemicals, and mold abatement. |
| very bulky compared to those that are produced | | | | The major benefit of HEPA filters is that they can |
| today. | | | | remove Volatile Organic Compounds (VOCs) |
| HEPA filters are able to trap 99.97% of particles | | | | which are the gases that are released from |
| having the size of 0.3 micron, including harmful | | | | household chemicals and synthetic materials. If |
| fibers, dust, smoke, pet dander, and more. With | | | | filtration systems do not contain HEPA filters, all |
| the capacity to collect dirt particles, which are 1 | | | | the toxic particles trapped in the room are left |
| 300th the width of the human air, these filters | | | | unfiltered. The price of portable HEPA filter unit |
| have high resistance power and cannot be placed | | | | ranges from approximately $100 to $3500, |
| directly in heating or cooling systems. | | | | depending on the size of the unit. |