1. How Much Air Can You Exhale

2. An average adult can move about 500 milliliters of air into and out of the lungs with each breath. This amount of air is called the tidal volume.
The amount of air that a person can forcibly exhale after breathing in as much air as possible is the vital capacity.
(adult male = 4800 mL, adult female = 3200 ml)

3. Even after one forces as much air out as possible, about 1200 mL of air remain in the lungs. This is called the residual volume.
Residual volume protects against lung collapse and makes sure there is air remaining in the alveoli for gas exchange.

4. Total lung capacity is the sum of vital capacity and residual volume
Total lung capacity is the sum of vital capacity and residual volume. The total lung capacity of a healthy adult male is 6000 mL.
Vital capacity depends on body, size, age and strength of respiratory muscles.

5. Disease that affect the lungs are:
Allergies
Bronghitis
Cancer
Emphysema
Asthma
Tuberculosis
pneumonia

6. Lung capacity may be decreased as a result of the swelling of lung tissue, accumulation of fluids and rupture of alveoli.
Smoking damages the cilia and white blood cells that protect the respiratory tract and it causes the lungs to produce more mucus. This may reduce the surface area available for gas exchange and promote growth of harmful bacteria.

7. As people age, the lungs become more rigid and are not as elastic
As people age, the lungs become more rigid and are not as elastic. This results in a decreased vital capacity.
Macraphages are cells that clean the respiratory tract. As a person ages, these also become less effective.

8. People who are physically active need more oxygen than people who are resting. They also produce more carbon dioxide because they move more air by increasing their tidal volume (breathing more deeply) and respiratory rate (breathing more often)