Ventilation (per ASHRAE 62.1 definition) is the process of

• A. Process of supplying air or removing air from a space to control contaminant levels, humidity, or temperature within the space
• B. Process of cooling the air
• C. Process of filtering air only
• D. Process of heating air only

Answer: (A)

Ventilation, as defined by ASHRAE 62.1, is the intentional exchange of air with the outdoors—the process of supplying outdoor air to a space and removing indoor air from it—in order to control contaminant levels, humidity, and temperature within the space. This captures the idea of diluting indoor pollutants, managing moisture, and helping maintain comfort by bringing in fresh air and exhausting stale air. It’s not just about cooling or heating, which are thermal adjustments handled by conditioning, nor is it only about filtration, which removes particles without necessarily exchanging air with the outside. Ventilation can be provided mechanically or through natural means, and ASHRAE 62.1 sets the minimum outdoor-air quantities to achieve acceptable indoor air quality.