advanced practice nurse a registered nurse having education beyond the basic nursing education and certified by a nationally recognized professional organization in a nursing specialty, or meeting other criteria established by a Board of Nursing.
Quick Answer. The air that makes up Earth's atmosphere contains 20.9 percent oxygen. This is true up to about 70,000 feet above sea level. However, above 10,000 feet, the atmosphere becomes too thin to support human life, even though its proportions do not change much. Continue Reading.
Oxygen makes up 21% of the air around us. In exhaled air, this reduces to 15% in exhaled air. Each breath exchanges a volume of 500ml of air between our lungs and the surroundings, known as the tidal volume. So, a reduction of 6% of oxygen means that we consume 30ml of oxygen per breath. Normal breathing rate is at 12breath/min, corresponding to an oxygen consumption of 360ml/min.