air change rate

The air change rate refers to how many times the entire volume of air inside a space is replaced with fresh air within an hour. It's a measure of ventilation efficiency; higher rates mean fresher, cleaner air and better removal of indoor pollutants. For example, an air change rate of 6 per hour indicates that the air inside the room is fully refreshed six times every hour. Proper ventilation helps maintain good indoor air quality, reducing health risks from pollutants, odors, and humidity. This rate varies depending on the space's use and the ventilation system design.