What is ventilation?

• A. The process of supplying outdoor air to indoor spaces; it maintains IAQ and comfort.
• B. The process of filtering indoor air without outdoor air.
• C. The process of heating indoor spaces using indoor air.
• D. The process of removing moisture from air only.

Answer: (A)

Ventilation is the process of supplying outdoor air to indoor spaces to maintain indoor air quality and comfort. By bringing in fresh outside air and exchanging it with indoor air, ventilation dilutes pollutants, odors, and excess moisture, and helps keep CO2 levels comfortable for occupants. It can happen naturally (opening windows) or mechanically (using fans and ducts to move air in and out). This is different from filtration (which cleans air but may not bring in outdoor air), dehumidification (which removes moisture without refreshing the air), or heating (which changes temperature without necessarily introducing fresh air).