What is the purpose of a negative air machine in containment?

• A. To create negative pressure and limit dust migration outside the containment
• B. To heat the air
• C. To humidify
• D. To increase airflow

Answer: (A)

Creating negative pressure inside the containment is the central idea. The negative air machine draws air from the surrounding space into the containment and pushes it through a HEPA filter before it’s exhausted, which keeps dust and contaminants from escaping to adjacent areas. This maintained negative pressure ensures any leakage would be air flowing inward rather than outward, reducing cross-contamination. Heating, humidifying, or simply increasing general airflow do not achieve containment protection; without filtration and a controlled pressure difference, dust can migrate outside the work zone.