Question

Inside your nose structure detect ... in the air these structures send messages to the

Answer 1

This description is unspecific and is confusing...

The nose has different functions mainly for inhalation of oxygen and exhalation of carbon dioxide which is called the respiration process or gas exchange. As a sensory organ, the nose has also another function which is olfaction, the ability to smell.
Olfaction in a biopsychological term, is the process by which sensory information recognized by the nasal receptors are transduced in a understandable and recognizable stimulus or rather perception, in simplest term is to smell.

Therefore, nasal receptors are the structures that send messages to the facial nerve which is responsible for sending the information to the brain for it to be perceived and acknowledge.