What is the primary purpose of sounding air horns after an emergency evacuation notice?

The primary purpose of sounding air horns after an emergency evacuation notice is to provide a warning signal on-scene. This audible alert serves to ensure that all personnel on the scene are aware of the need to evacuate or seek shelter. It can also help to gather attention quickly, as air horns can be heard over background noise typically present at emergency scenes. This is crucial for maintaining safety and ensuring that everyone is aware of the situation and the necessary actions to take.

In the context of emergency operations, clear communication and signals are essential; therefore, using air horns helps to centralize awareness among all individuals present, facilitating a more orderly response to a dangerous situation. The other choices may involve related actions, but they do not capture the specific function of the air horns in this context.