Extraction is a term that describes the primary process of extracting or pulling the fumes from a source. In this case, the source of fumes is the laser enclosure. The term filtration describes the secondary process of removing/capturing contaminants from the fume laden air using filters.
A common alternative secondary process is called venting. Venting describes the process of sending the extracted fumes to the outdoors. Therefore, filtered fume extractors usually refers to a machine that pulls fumes from a laser enclosure, filters the fumes out, and recirculates clean air back into the room. A venting blower or extractor generally refers to a specialized fan and duct system which pulls fumes from the laser enclosure and pushes the untreated pollutants directly outside into the environment.
-Chau Vo, PAT Technology