What term describes the duration an agent remains in a specific area?

The term that describes the duration an agent remains in a specific area is "persistence." In the context of military operations or environmental science, persistence refers to how long a substance, such as a chemical agent or contaminant, lasts in a particular environment without degrading or being removed. This is an important concept as it influences the potential impact of the agent on the area and the strategies that need to be employed for mitigation or response.

In contrast, concentration refers to the amount of an agent present in a certain volume, which does not directly address the duration it remains in the area. Transience implies a short duration or temporary presence, which is opposite to the concept of persistence. Mobility, on the other hand, refers to the ability of an agent to move or be transported from one location to another, not its duration in a specific location.