Air in an occupied space must be kept moving to eliminate ________.

• A. Stratification
• B. Drafts
• C. Humidity
• D. Odor

Answer: (A)

Preventing stratification is the goal of keeping air moving. In a room, warm air tends to rise toward the ceiling while cooler air stays near the floor, forming distinct temperature layers. When the air is still, these layers persist, causing uncomfortable temperature differences and wasting energy. By circulating and mixing the air, those warm and cool layers are disrupted, producing a more uniform temperature throughout the occupied space. While drafts, humidity, and odors are related HVAC concerns, the primary reason for moving air in this context is to eliminate that vertical separation of air temperatures—stratification.