The proper choice of respiratory protection is an important process that involves many factors. The most obvious factor for consideration is the type of hazard — i.e., the chemical or substance that must be protected against. This drives whether or not a chemical cartridge must be used, a particulate filter, a combination of both, or a higher level of protection. The concentration of the contaminant will drive whether a half-mask, full-face, or higher level or protection is needed. Full-face respirators must also be considered when eye protection is required to protect from things such as irritants, or skin and mucosa absorption.
Still other factors, such as chemical resistance of the materials making up the respirator, temperature of the environment in which the respirator is to be used, and how the respirator will be cleaned and serviced must be considered. Visibility, frequency and duration of use, and fit are also important considerations in the selection process. Of course, when respirators are required in the workplace all these, as well as other program elements, must all be incorporated into the written comprehensive respiratory protection program.