What is indicated by a slight positive pressurization in air processing systems?

A slight positive pressurization in air processing systems indicates that there is more air being supplied into the space than being exhausted. This situation typically exists when the system is designed to introduce a significant amount of conditioned air while having only a limited amount of return air, hence the description of "most air is returned with a small amount of make-up air" aligns with this scenario.

In a positive pressurization condition, the excess air creates a slight pressure differential that helps push contaminants out of the building, contributing to better indoor air quality. This is essential in environments where maintaining specific indoor conditions is necessary, such as controlled spaces in healthcare or laboratories. The slight positive pressure helps to ensure that the air quality remains high, preventing external pollutants from infiltrating.

The other choices suggest scenarios that do not align with the dynamics of a system exhibiting slight positive pressurization. For instance, the belief that more air leaves the building than enters contradicts the definition of positive pressurization, as that would imply negative pressure. Similarly, stating that air is only introduced without any return does not hold true in a properly functioning system as certain amounts of return air are always necessary for balance. Lastly, the idea that it leads to a complete neutral balance of air would