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.
A Discovery Health answered. The percentage of oxygen is the same at sea level as it is at high altitudes, which is roughly 21 percent. However, because air molecules at high altitudes are more dispersed, each breath delivers less oxygen to the body. A breath at 12,000 feet (3,657.6 m), delivers 40 percent less oxygen to the body than it does at sea level. At 18,000, feet, a breath takes in 50 percent less oxygen.