Which statement about ventilation is true?

Which statement about ventilation is true?

• A. It only recirculates indoor air.
• B. It filters air through specialized filters.
• C. It is the mechanical process of supplying or removing air to and from a space, bringing outside air into the conditioned space.
• D. It has no impact on air exchange.

Answer: (C)

Ventilation is the controlled exchange of air between indoors and outdoors to dilute contaminants and maintain comfort. The statement describes it as the mechanical process of supplying or removing air to and from a space, bringing outside air into the conditioned space. That captures the essential function: bringing in outdoor air and exhausting indoor air so the indoor environment isn’t just a closed loop. This is different from recirculation, which moves indoor air around without introducing outside air, and from filtration, which removes particles from the air rather than changing the air itself. Ventilation directly impacts the air exchange rate, IAQ, and humidity because it determines how much fresh outdoor air enters and how much stale air is expelled.

Ventilation is the controlled exchange of air between indoors and outdoors to dilute contaminants and maintain comfort. The statement describes it as the mechanical process of supplying or removing air to and from a space, bringing outside air into the conditioned space. That captures the essential function: bringing in outdoor air and exhausting indoor air so the indoor environment isn’t just a closed loop. This is different from recirculation, which moves indoor air around without introducing outside air, and from filtration, which removes particles from the air rather than changing the air itself. Ventilation directly impacts the air exchange rate, IAQ, and humidity because it determines how much fresh outdoor air enters and how much stale air is expelled.