Nasal cavity larynx nasopharynx trachea. in the lungs.
I believe that ,Exhalation begins when the internal intercostal muscles contract.
Exhalation happens due to elastic properties of the lungs as well as the internal intercostal muscles which lower the rib cage and decrease the thoracic volume. As the thoracic diaphragm relaxes during exhalation it causes the tissue it has depressed to rise superiorly and put the pressure on the lungs to expel the air.