What are the two categories of respiratory protection equipment?

The two primary categories of respiratory protection equipment are self-contained breathing apparatus (SCBA) and air-purifying respirators (APR). SCBA provides breathable air from a tank and is used in environments that are immediately dangerous to life and health, whereas APR filters contaminants from the air and is suitable for atmospheres that contain less hazardous levels of pollutants.

In this context, ASRs refers to air-supplying respirators, while APRs refers to air-purifying respirators. Both of these serve crucial roles in various environments, but they are distinct types of equipment charged with specific purposes. The terms must be used correctly to avoid confusion in referring to the functionality of respiratory protection gear.

The answer choice that combines ASRs (air-supplying) with APRs (air-purifying) captures the right classification, highlighting the broader spectrum of respiratory protection options available for firefighters and ensuring safety in different atmospheres encountered during operations.