What are the two main types of respirators used?

The correct choice identifies the two main types of respirators based on their function in protecting the user from hazardous atmospheres. Air-purifying respirators work by filtering out harmful contaminants from the air, allowing the user to breathe cleaner air. They are commonly used in environments where there are airborne particles, vapors, or gases that can be removed effectively through filtration.

Atmosphere-supplying respirators, on the other hand, provide the user with a separate supply of breathable air, independent of the surrounding environment. This is crucial in situations where the air may be too contaminated or oxygen-deficient for safe breathing.

The distinction between these two types is fundamental to understanding respiratory protection as it addresses different scenarios and types of exposure. Workers need to choose the appropriate respirator based on the nature of the hazardous materials they might encounter and the characteristics of the environment.

Other options mix elements that don't comprehensively capture the two primary categories that relate directly to how respirators function in various hazardous situations.