Present Status of Air Filters and Exploration of Their New Applications

図 Abstract Air filters have been commonly used for the removal of airborne particles. Currently the major concerns of air filters are （ 1 ） improvement of collection performance - a filter with a low pressure drop and a high collection efficiency, （ 2 ） influence of dust load on filter performance - prediction of filter life and development of a filter with a longer life, and （ 3 ） collection efficiency of nanoparticles - thermal rebound of sub -10 nm particles on fiber surfaces. In addition to the conventional usages of air filters, they may also be used for the classification of aerosol particles by tuning the filter structure and filtration conditions. Inertial filter is a low - pass filter, which may be used for the sampling of atmospheric particles and continuous measurement of PM 2 . 5 or PM 0 . 1 . The bounce - off of particles on fiber surfaces may be utilized to achieve “sieving” of aerosol particles. Another topic of filter is the collection efficiency of air filter for PM 2 . 5 . Combination of centrifugal force with air filter may solve many problems which the conventional air filters are confronted with now.