What is the supervisor's responsibility regarding breathing air quality?

• A. Monitor air temperature
• B. Ensure air meets required purity standards
• C. Document dive duration
• D. Check buoyancy calculations

Answer: (B)

Breathing air quality must meet purity standards before divers use it, and that is the supervisor’s responsibility. The supervisor ensures the air being used to fill cylinders comes from a certified, tested source and meets the applicable purity requirements. This means supervising the air supply system—compressors, filtration and drying equipment, and any gas available in air banks—so that contaminants such as moisture, oil, particulates, or harmful gases are kept within limits. Proper documentation and testing records accompany the air supply, and those records must show the air meets the required standards before diving occurs. If the air fails to meet the standards, it must not be used and corrective actions taken.

Air temperature, while relevant to equipment operation and storage, is not the main safety concern tied to breathing air quality. Documenting dive duration and checking buoyancy calculations pertain to records and dive planning, not to the integrity of the breathing gas itself.