What is the average oxygen content in the air?

The average oxygen content in the air is approximately 21%. This percentage is based on the composition of Earth's atmosphere, where nitrogen makes up about 78% of the air, and the remaining 1% consists of other gases, including carbon dioxide, argon, and trace gases. The presence of 21% oxygen is vital for combustion processes and for the respiratory needs of most living organisms. Understanding this baseline is essential for fire inspectors, as various fire-related phenomena, including fire behavior and fire prevention strategies, are closely tied to the availability of oxygen. An accurate grasp of these atmospheric conditions is crucial when assessing fire safety and effectiveness in both residential and commercial environments.