What is the effect of maintaining a lower pressure in a negative-pressure room?

• A. It prevents contaminated air from escaping to other areas.
• B. It draws air from adjacent rooms into the room.
• C. It vents air directly outside.
• D. It equalizes pressure with surrounding areas.

Answer: (A)

The main idea here is containment through a pressure difference. A negative-pressure room stays at lower pressure than surrounding areas, so air tends to flow from the halls into the room rather than from the room out into hallways. This inward flow helps keep contaminated air from reaching other parts of the building. The air inside the room is then handled by the building’s ventilation system, often matching with filtration or exhaust to outside, so any contaminants are removed before air is released. That containment—the contaminated air staying in the room and being exhausted safely—is why this setup is chosen. Air moving inward is part of how it works, but the critical outcome is preventing contamination from escaping to other areas. The idea of equalizing pressure or simply venting outside without containment would not achieve that protection.