There are a couple dozen other elements that are in there in trace amounts, but to a first approximation you're just a bag of carbon, oxygen, and hydrogen. Now, it turns out that the atmosphere is a bag of carbon, oxygen, and hydrogen as well, and it's not living.
Cigarette smoking is the most common irritant that causes emphysema. Pipe, cigar, and other types of tobacco smoking can also cause emphysema, especially if the smoke is inhaled. Fumes and Dust. Breathing in other fumes and dusts over a long period of time may also cause the disease.
Emphysema is a condition in which the inflammation in the lungs causes the dilation and destruction of alveoli. In addition to the loss of alveoli, the cellular walls of air sacs begin to harden and lose their elasticity. This makes it difficult to expel air from the lungs (a condition called air trapping). This explains why exhaling rather than inhaling is usually more difficult in people with emphysema. Pneumonia is an infection that inflames the alveoli in one or both lungs and can result in the air sacs filling with pus.