Final answer:
An SCBA that releases exhaled air into the atmosphere is known as an Open-circuit breathing apparatus, used where air quality is compromised, and it doesn't recycle exhaled air.
Step-by-step explanation:
An SCBA in which the exhaled air is released into the atmosphere and is not reused is called an Open-circuit breathing apparatus. This type of breathing apparatus is commonly used by firefighters and rescue personnel, allowing them to breathe clean air in environments where the air quality is compromised. The exhaled air in an open-circuit system is directly vented into the surrounding environment, as opposed to being recycled within the apparatus.