What is the approximate amount of oxygen present in expired air?

The correct amount of oxygen present in expired air is approximately 16.4%. This value reflects the typical composition of air that we breathe out, which is lower in oxygen content than the air we inhale. Inhaled air contains about 21% oxygen, but during respiration, the body uses some of this oxygen for metabolic processes, resulting in a lower concentration in expired air.

The typical values for the composition of expired air are around 16-18% for oxygen. This range indicates how efficient the body is at utilizing oxygen during the process of cellular respiration. The presence of carbon dioxide levels in expired air also increases, representing the waste products of metabolic activity, further affirming that the oxygen content falls within this range. Understanding the composition of expired air is essential in clinical settings, as it can aid in assessing a patient’s respiratory function and overall health.