ABSTRACT
Air is a mixture of inert and metabolic gases, composed of nitrogen and oxygen mainly, with variable amounts of carbon dioxide, water vapor, ozone, sulfur dioxide, and nitrogen dioxide, and fixed trace amounts of xenon, helium, krypton, argon, methane, nitrous oxide, hydrogen, and neon. By volume, air is 78.1% nitrogen, 20.9% oxygen, and 1% everything else. Over nominal pressure and temperature ranges encountered in the Earth’s atmosphere, air can be treated as an ideal, or dilute, gas.
