Air Composition

Dry air is a mechanical mixture of nitrogen, oxygen, carbon dioxide and more

Air is a mixture of gases - 78% nitrogen and 21% oxygen - with traces of water vapor, carbon dioxide, argon, and various other components. Air is usually modeled as a uniform (no variation or fluctuation) gas with properties averaged from the individual components.

• The water or vapor content in air varies. The maximum moisture carrying capacity of air depends primarily on temperature
• The composition of air is unchanged until elevation of approximately 10.000 m
• The average air temperature diminishes at the rate of 0.6^oC for each 100 m vertical height
• "One Standard Atmosphere" is defined as the pressure equivalent to that exerted by a 760 mm column of mercury at 0^oC sea level and at standard gravity (32.174 ft/sec²)

Other components in air

• Sulfur dioxide - SO₂ - 1.0 parts/million (ppm)
• Methane - CH₄ - 2.0 parts/million (ppm)
• Nitrous oxide - N₂O - 0.5 parts/million (ppm)
• Ozone - O₃ - 0 to 0.07 parts/million (ppm)
• Nitrogen dioxide - NO₂ - 0.02 parts/million (ppm)
• Iodine - I₂ - 0.01 parts/million (ppm)
• Carbon monoxide - CO - 0 to trace (ppm)
• Ammonia - NH₃ - 0 to trace (ppm)

Common Pressure Units frequently used as alternative to "one Atmosphere"

• 76 Centimeters (760 mm) of Mercury
• 29.921 Inches of Mercury
• 10.332 Meters of Water
• 406.78 Inches of Water
• 33.899 Feet of Water
• 14.696 Pound-Force per Square Inch
• 2116.2 Pounds-Force per Square Foot
• 1.033 Kilograms-Force per Square Centimeter
• 101.33 Kilopascal

More about Temperature, Density, Specific heat, Thermal Conductivity - the properties of air.

Resources, Tools and Basic Information for Engineering and Design of Technical Applications!