Air filter
An air filter is a device which removes solid particles, such as dust, pollen, mold, and bacteria from air.
They are often used in internal combustion engines, gas compressors, diving air compressors and ventilation systems.
Engine intakes tend to use either paper or foam filters. Paper filters are primarily used by racers but tend to be more brittle. Buildings, on the other hand, use a denser foam in their air vents for cleaner air quality, as well as planes and other man-made environments (i.e. satellites and space shuttles), for cleaner air. Another, but not so often used method, is using static fibers to catch small pieces of particulate matter. These fibers are much like the ones on a Swiffer dusting pad. This method is for a much smaller scale.