Generally speaking, air filters are physically simple but technically complex devices. Whether they are particulate or gas phase filters, they rely on a complex set of mechanisms to perform their function satisfactorily. In many cases, more than one of these mechanisms comes into play.

Many new technologies have been employed in the effort to improve the quality and performance of air filters, and in some cases to reduce their cost. The most notable areas where advancement has been pursued are reduction in pressure drop and elimination of biological contaminants in the filter media. It is important to consider whether applying new technologies to air filter products is necessary and functional. In many cases it is, but in some cases it's not. Certain technologies, like ionic air cleaners, may produce by-products that can be harmful to people or the environment.

This section offers an overview of air filtration technology, and provides a foundation from which you can converse with others about how air filters work. Remember: creating an air filter that is 100% efficient on the target contaminant, has zero pressure drop, and produces no by-products is the goal of all air filter researchers.