Is it Breathing Pure Oxygen Going To kill you?

Why does breathing pure oxygen kill you?

So you might think that breathing 100 percent oxygen would be good for us -- but actually it can be harmful. So, the short answer is, pure oxygen is generally bad, and sometimes toxic.If we breath pure oxygen it is very harmful to health because we require oxygen to live and we breathe air in which contains only 21 percent oxygen. And Our blood has evolved to capture the oxygen we breathe in and bind it safely to the transport molecule called hemoglobin. If you breathe air with a much higher than normal O2 concentration, the oxygen in the lungs overwhelms the blood's ability to carry it away.

The result is that free oxygen binds to the surface proteins of the lungs, interferes with the operation of the central nervous system and also attacks the retina.Contrary to popular myth, hyperventilating air at ordinary pressures never causes oxygen toxicity (the dizziness is due to CO2 levels dropping too low), but breathing oxygen at pressures of 0.5 bar or more (roughly two and a half times normal) for more than 16 hours can lead to irreversible lung damage and, eventually, death.

Now what would happen if you breathed 100 percent oxygen? In guinea pigs exposed to 100 percent oxygen at normal air pressure for 48 hours, fluid accumulates in the lungs and the epithelial cells lining the alveoli. In addition, the pulmonary capillaries get damaged. A highly reactive form of the oxygen molecule, called the oxygen free radical, which destroys proteins and membranes in the epithelial cells, probably causes this damage. 

In humans breathing 100 percent oxygen at normal pressure, here's what happens:

• Fluid accumulates in the lungs.
• Gas flow across the alveoli slows down, meaning that the person has to breathe more to get enough oxygen.
• Chest pains occur during deep breathing.
• The total volume of exchangeable air in the lung decreases by 17 percent.
• Mucus plugs local areas of collapsed alveoli -- a condition called atelectasis. The oxygen trapped in the plugged alveoli gets absorbed into the blood, no gas is left to keep the plugged alveoli inflated, and they collapse. Mucus plugs are normal, but they are cleared by coughing. If alveoli become plugged while breathing air, the nitrogen trapped in the alveoli keeps them inflated.