What is the purpose of a nebulizer?

Answer 1

It puts fine water droplets in the air flow.

This can increase humidity of the air you breath.

If pure water mist is inhaled it can cause productive coughing ...

in normal saline is nebulized it can ease breathing and/or liquefy mucous.

Answer 2

Nasal irrigation is used to clear infected sinuses or may be performed after surgery to the nose region. It may be performed by adding antibiotics to the solution to treat nasal polyps, nasal septal deviation, allergic nasal inflammation.