The nose and nasal cavity perform a number of functions, including
- Providing us with a sense of smell.
- Warming and moistening the air that is breathed in.
- Filtering the air that is breathed in of irritants, such as dust and foreign matter.
- Assisting in the production of sound.
The nose is the preferred route to deliver oxygen to the body as it is a better filter than the mouth. The nose decreases the amount of irritants delivered to the lung, while also heating and adding moisture (humidity) into the air we breathe.
When large amounts of air are needed, the nose is not the most efficient way of getting air into the lungs. In these situations, mouth breathing may be used. Mouth breathing is commonly needed when exercising.
Infection or irritation of the nasal cavities can result in swelling, a runny nose or blocked sinuses, which can interfere with breathing.