The nasal passage is a channel wherein air flows through the nose. Respiratory mucous membranes with many hair-like cells line the walls of this passage.
These membranes trap substances such as dust and bacteria as an individual inhales them. Having entered the mucous membrane in the nose, these substances safely travel into an individuals gastric juices where they are not as harmful. These tiny cells ensure that dust and similar small particles do not enter an individuals respiratory system and cause health problems. The nasal passage also contains small patches of tissue called olfactory membranes, which are responsible for an individuals sense of smell. When air rushes past the olfactory membranes, a scent is transmitted to an individual, which is why the quick rushes of air that occur during sniffing often provide a heightened sense of smell.