Air Filters

Air filters, also called air purifiers, are used for home, hospital, and industrial applications. Their purpose is to filter pollutants and contaminants from the ambient air that we breathe. Air filters purify the air through the use of air filters using charcoal absorption, ionizing techniques, or mechanical filters.



Why Use Air Filters?

In recent years, air filters have increased in popularity in part due to studies released by organizations such as the U.S. Environmental Protection Agency (EPA) and the American Lung Association that show indoor air quality is not as good as it should be. People who suffer from allergies, especially mold, pollen, animal dander, and dust benefit most from the use of air purifiers.

High Efficiency Particulate Air (HEPA) Filters

High Efficiency Particulate Air (HEPA) filters were developed by the Department of Energy in the 1940s to filter radioactive particles from exhaust systems in nuclear reactor facilities. HEPA filters are required by law to filter out more than 99.97% of dust, mold, pollen, bacteria, and particulate matter less than 0.3 microns in size.

Those with severe allergies or asthma should use specialized HEPA filters. Also, these filters are frequently found in areas that need to be dust- and particle-free such as:

  • Hospitals
  • Industrial and manufacturing facilities
  • Pharmaceutical industry
  • Electronics industry.

Purchasing Air Filters

Although using an air filter in the home may serve to reduce allergens in ambient air, it is not a cure-all, especially since not all air filters are created equally. HEPA filters are manufactured to strict compliance, but the label must indicate its authenticity. When buying an air filter or purifier, there are several considerations to keep in mind including:

  • Selecting the proper size air filter
  • Noise level
  • Filter efficiency
  • Filter maintenance (how often it needs to be changed)
  • Size
  • Physical appearance.

The efficiency of the filter is gauged by what is referred to as the Clean Air Delivery Rating (CADR). The higher the rating, the more efficient the air filter. The CADR was developed by the Association of Home Appliance Manufacturers to aid consumers in choosing the best air filter for their needs. The CADR also has a bearing on what size air filter to purchase.

The most important consideration when purchasing an air filter is choosing the correct size air filter for the room. The formula that is used to determine this is CADR = the square feet of the room x 0.75.