What does the term 'air changes per hour' refer to in filtration?

The term 'air changes per hour' specifically refers to B, which is the number of times the total volume of air in a given space is replaced within one hour. This metric is crucial in understanding ventilation and air quality in various environments, particularly in settings that require specific air purity levels, such as hospitals, laboratories, and industrial facilities.

This measure helps determine how effectively a space is being ventilated. For example, if a room has an air change rate of 6 air changes per hour, it means that the entire volume of air in the room is replaced six times within that hour. Higher air change rates often indicate better ventilation, which can lead to lower concentrations of indoor pollutants and improved air quality.

The other choices relate to different aspects of air filtration but do not define the concept of 'air changes per hour.' Speed of air entering a room pertains to airflow dynamics but does not quantify how often the air is replaced. The efficiency of a filter refers to how well it captures particles from the air but does not measure the frequency of air exchange. The volume of air processed by a filter relates to the capacity or output of a filtration system, which again is not a direct indication of air changes per hour. Thus, the definition that correctly identifies