What will happen if the respiratory tract is not moist ?

Explanation

(1)If the respiratory tract is not moist the dirt particles in the inhaled air will not be removed from air in the nasal cavities and reaches lungs and create problems to lungs.
(2)The temperature of the inhaled air is brought close to that of the body for the smooth passage in the respiratory tract . If it is dry, It is not possible .
(3)If the surface dries out , gas exchange will happen at a very reduced rate since fast moving gaseous oxygen molecules do not efficiently cross the alveoli membrane .
(4)The reduced gas exchange is most likely not enough to support blood oxygenation for vital functions.
(5)Hence respiratory tract should be moist for smooth exchange of gases.