The function of a respirator is to protect the wearer from respiratory hazards. Personal protective equipment is typically the last line of defence. Employers are required to provide workers with suitable personal protective equipment, while workers have the responsibility to care for those devices. Without proper care, the protective qualities of the respirator could be compromised, potentially causing the worker to be exposed to hazards that could impact their health and safety. A checklist can help a worker properly inspect and care for a respirator. As a minimum, follow the manufacturer's recommendations for care of the respirator. 

Respiratory protective masks (usually called respirators) are used whenever airborne contaminants are present and cannot be economically controlled by engineering means or administrative controls. Respirators come in many forms, including popular filtering facepiece respirators (FFRs), one-quarter, one-half, and full facepiece masks, and filtering air-purifying respirators (APR), air-supplied respirators, blower powered air-purifying respirators (PAPR), and self-contained breathing apparatus (SCBA). They are used by personnel in homes, industry, agriculture, mines, emergency first responses, medicine, and the military wherever airborne contamination is a possible threat. The threats may be from gases, vapors, dusts, and particulates of various sizes, including aerosols .

Although the protective mechanisms of respirators are largely physical and sometimes chemical, wearing respirators come with a host of physiological and psychological burdens. These can interfere with task performances and reduce work efficiency. These burdens can even be severe enough to cause life-threatening conditions if not ameliorated. Quantitative assessments of these burdens have been made so that respirator design trade-offs, wearer usages, and regulations can accommodate the needs of the wearer.