Air Filtration

Air filtration is the process of removing contaminants from air.  There are several other means of removing particles from air without going through any types of porous substances, such as scrubbers, cyclones and electrostatic precipitators.  Since fibrous materials are relatively inexpensive maintaining relatively high level of protection, and are simple to operate, air filtration through fibrous materials is widely used and a very popular among the air filtration industry.  

Air filtration was originated to protect equipment or valuable substances.  The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) has released Standard 62-2001 “Ventilation for Acceptable Indoor Air Quality” which requires minimum of MERV (Minimum Efficiency Reporting Value (MERV) 6 for the buildings in 2001.  This represents an average efficiency more than 35% at 3 to 10 micrometer particles.  After 9/11, awareness of air filtration systems to protect building environments for commercial/industrial and residential HVAC (heating, ventilating and air-conditioning) units has substantially been increased. Indoor Air Quality (IAQ) is becoming a dominant concern for human health effect.  

People spend most of their time indoors.  Indoor pollutant levels are generally two to five times higher than the outdoor’s.  As the EPA pointed out the importance of human health effect associated with environment, Indoor Air Quality (IAQ) is a dominant concern for us. Allergens affect more than half the population in the world.

Following the implementation of the PM2.5 standards along with PM10 (NAAQS: National Ambient Air Quality Standards), people paid more attention to the fine particles.  There is a strong correlation between the level of particles in outdoor ambient air with the level found in the indoor environment.  Since there are much more particles indoors than in the ambient, an effective filtration system is needed to remove these particles.

Although the forced air ventilation residential filters are very unique to North America, these forced air ventilation systems have been increasingly utilized in commercial and industrial buildings all over the world.  Due to the mechanical limitation of air circulating blowers, the pressure drop of these filters is a very critical factor.

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