Negative pressure in a room means that the air pressure inside the room is lower than the air pressure outside. This causes air to flow into the room, but not escape from it — even when the door is opened.

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Purpose of Negative Pressure Rooms:

Used in healthcare settings to prevent the spread of infectious airborne diseases like:

• Tuberculosis (TB)
• COVID-19
• Measles
• Varicella (chickenpox)

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How It Works:

• A ventilation system pulls more air out of the room than is let in.
• Exhaust air is filtered through HEPA filters or directed outside.
• This keeps germs inside, protecting people in nearby areas.

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Examples of Where Used:

• Isolation rooms (AIIRs)
• ICUs
• Laboratories
• Operating rooms (for infected patients)

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