ABSTRACT
In principle, respirators are classifi ed into two types: air-purifying respirators and atmosphere-supplying respirators. The air-purifying respirator removes contaminants from the ambient air, and the atmosphere-supplying respirator provides air from a source other than the surrounding atmosphere. Both types can be further subclassifi ed by the type of inlet covering and the mode of operation. Figure 2.1 shows the subclassifi cations of respirators for particulate matter.
