What does the term "breathing air" refer to in SCBA usage?

The term "breathing air" in the context of SCBA (Self-Contained Breathing Apparatus) usage refers specifically to air that is free from contaminants and safe for human respiration. In various hazardous environments where firefighters and first responders operate, ensuring the air quality is essential to prevent exposure to toxic substances or harmful particulates. Breathing air must meet stringent quality standards, such as being free of carbon monoxide, carbon dioxide, and particulate matter, thereby enabling users to breathe safely without risking health or safety.

In an SCBA, the integrity of the supplied air is paramount for the protection of the user. Therefore, the air used must be specifically filtered and compressed to ensure it meets the required specifications for safe inhalation.