What term describes the condition in which the air pressure inside a contained area is lower than the outside air pressure?

What term describes the condition in which the air pressure inside a contained area is lower than the outside air pressure?

• A. Positive air pressure
• B. Neutral air pressure
• C. Negative air pressure
• D. Ambient air pressure

Answer: (C)

This describes a negative air pressure environment. When the air pressure inside a contained area is lower than the outside, air naturally flows into that space from the surrounding areas. In healthcare, maintaining negative pressure means that any air and potentially infectious particles are drawn into the room and exhausted to the outside, rather than escaping into adjacent spaces. This is achieved by exhausting more air than is supplied and by keeping the room well-sealed, often with monitoring to ensure the pressure differential stays in the desired range. In contrast, a room with higher inside pressure than outside pushes air outward (positive pressure), which helps keep outside contaminants from entering but can release indoor air into adjacent areas. Neutral air pressure means inside and outside pressures are about equal, so there isn’t a directional flow to contain contaminants. Ambient air pressure simply refers to the surrounding atmospheric pressure.

This describes a negative air pressure environment. When the air pressure inside a contained area is lower than the outside, air naturally flows into that space from the surrounding areas. In healthcare, maintaining negative pressure means that any air and potentially infectious particles are drawn into the room and exhausted to the outside, rather than escaping into adjacent spaces. This is achieved by exhausting more air than is supplied and by keeping the room well-sealed, often with monitoring to ensure the pressure differential stays in the desired range.

In contrast, a room with higher inside pressure than outside pushes air outward (positive pressure), which helps keep outside contaminants from entering but can release indoor air into adjacent areas. Neutral air pressure means inside and outside pressures are about equal, so there isn’t a directional flow to contain contaminants. Ambient air pressure simply refers to the surrounding atmospheric pressure.