When we exhale, the primary gas we release is carbon dioxide (CO2), along with other gases like nitrogen and traces of oxygen. This exhaled carbon dioxide does not spontaneously convert back into oxygen when it mixes with the surrounding air. Instead, it disperses and becomes diluted within the atmosphere.
The air we breathe is composed of approximately 21% oxygen, 78% nitrogen, and trace amounts of other gases, including carbon dioxide. When we exhale, the exhaled air containing carbon dioxide mixes with the surrounding air, and the concentration of carbon dioxide in that area increases slightly. This is a natural part of the carbon cycle.
However, the oxygen we inhale and the carbon dioxide we exhale are not directly interconverted during this process. Oxygen is absorbed by our lungs into the bloodstream, where it binds to hemoglobin and is transported to cells throughout the body to support various physiological processes. Conversely, carbon dioxide is produced as a byproduct of cellular metabolism and is carried back to the lungs through the bloodstream to be exhaled.
It's important to note that the process of converting carbon dioxide back into oxygen is typically carried out by plants through photosynthesis. During photosynthesis, plants utilize carbon dioxide, water, and sunlight to produce oxygen and glucose. Therefore, the oxygen we breathe in primarily comes from plants, as they release oxygen into the atmosphere as a byproduct of photosynthesis.