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.
These cases result in usually painless swelling of the face and neck, with an immediate onset, the crepitus (crunching sound) typical of subcutaneous emphysema, and often with subcutaneous air visible on X-ray. One of the main causes of subcutaneous emphysema, along with pneumothorax, is an improperly functioning chest tube.