Gone are the days when the term ‘air filtration’ used to immediately and exclusively imply particulate air filtration.  In today’s environment, premier health organizations such as the Centers for Disease Control’s – National Institute for Occupational Safety and Health (NIOSH) define air filtration as removing “unwanted material” from airstreams. The term “unwanted material” thereby further described as material removed via both –

1.         Particulate Air Filtration, and

2.         Gas-phase Air cleaning (for removing gases, vapors and odors)

The collection mechanisms for particulate filtration and Gas-phase air cleaning are different. Description of the principles governing particulate filtration and Gas-phase air cleaning provide an understanding of the most important factors one must consider when selecting or enhancing an air filtration system. A more detailed discussion of air filtration principles can be found in the National Air Filtration Association’s (NAFA) Guide to Air Filtration [NAFA 2001a] and the ASHRAE Handbook: HVAC Systems and Equipment [ASHRAE 2000].

Chemical or Gas-Phase air filters have been in use for over three decades now.  These specialty air filtration products scrub mal-odorous, corrosive, harmful and toxic gases from airstreams. At the onset, companies with access to information on gas scrubbing chemistry packaged different forms of gas removal chemical media and introduced them into ductwork or within HVAC configurations with the good intent to scrub problem gases from air streams.  Applications of this invention spanned across scrubbing corrosive gases to protecting electronics and air compressors in industrial facilities, treating air in a museum or archive, removing odors within office buildings or commercial establishments, treating air quality at airports, laboratories, hospitals, healthcare, etc.   But, due to little expertise in the physics of air, these inventions did not gain widespread use because of inherent product flaws such as high pressure drop, excessive dusting, uneven pressure drop and velocity gradients, ineffective chemical media utilization, excessive leakage, air by-pass and premature breakthroughs.

As air quality degrades globally, the highly specialized air treatment company – American Air Filter (AAF International®), now addresses this market need with innovative and advanced product offerings. Problems from currently employed technologies were revealed using evaluations employing cutting-edge air analysis technologies at AAF International’s Global R&D centers. 

In the new realm, with AAF International addressing Gas-phase air filtration, it can now be safely expected that gas-phase air filters are not being designed to operate in isolation anymore. Gas-phase filters are an integral part of any HVAC system, are to be governed by the physics of air, and need to be designed with a systems approach in mind. With the ultimate goal being to provide – “BETTER AIR”.