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      Air

      Air is a mixture of several molecules and atoms composing the earth atmosphere. Main components are nitrogen (78.09%vol in dry air) , oxygen (20.95%vol in dry air) and argon (0,93%vol in dry air). Small quantities of helium, neon, xenon and krypton are also to be found. Carbon dioxide, water, methane, ozone as well as other molecules involved into natural and human (local) activities are also present in the atmosphere. Those quantities vary from on site to another and with time.

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      Air

      Air is a mixture of several molecules and atoms composing the earth atmosphere. Main components are nitrogen (78.09%vol in dry air) , oxygen (20.95%vol in dry air) and argon (0,93%vol in dry air). Small quantities of helium, neon, xenon and krypton are also to be found. Carbon dioxide, water, methane, ozone as well as other molecules involved into natural and human (local) activities are also present in the atmosphere. Those quantities vary from on site to another and with time.

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      Air

      Physical Properties

      Under solid (grey), liquid (blue) and vapor states (white) along the equilibrium curves

      • General properties
      • Solid phase
      • Liquid Phase
      • Gas Phase
      (P)
      log(P)
      Download
      • Molecular weight
        28.96
        g/mol
      • Content in air
        /

      Critical Point

      • Temperature
        - 140.6
        °C
         - 221.08 °F 132.55 K
      • Pressure
        37.663
        bar
         3.7663E6 pa 546.2554 lbf/in2 37.1705 Atm 3766.3 Kpa 2.825E4 mmHg
      • Density
        319.93
        kg/m³
         19.9725 lb/ft³

      Triple Point

      • Temperature
        /
      • Pressure
        /
      Pressure 1.013 bar
      • Melting point
        - 214
        °C
         - 353.2 °F 59.15 K
      • Latent heat of fusion (at melting point)
        /
      • Solid density
        /
      Pressure 1.013 bar
      • Liquid density
        /
      • Boiling point
        /
      • Latent heat of vaporization (at boiling point)
        /
      Pressure1.013barTemperature
      • Compressibility factor Z
        9.994E-1
        9.996E-1
        9.997E-1
      • Cp/Cv ratio γ
        1.4028
        1.4022
        1.4018
      • Dynamic viscosity
        1.7218E-4
        Po
         17.218 µPa.s 1.7218E-5 PA.S 1.157E-5 lb/ft/s
        1.7962E-4
        Po
         17.962 µPa.s 1.7962E-5 PA.S 1.207E-5 lb/ft/s
        1.849E-4
        Po
         18.49 µPa.s 1.849E-5 PA.S 1.2425E-5 lb/ft/s
      • Gas density at boiling point
        /
        /
        /
      • Gas density
        1.292
        kg/m³
         8.0657E-2 lb/ft³
        1.225
        kg/m³
         7.6474E-2 lb/ft³
        1.184
        kg/m³
         7.3915E-2 lb/ft³
      • Heat capacity at constant pressure Cp
        1.0059
        kJ/(kg.K)
         2.4042E-1 BTU/lb∙°F 1005.905 J/kg∙K 2.4042E-1 kcal/kg∙K
        1.0062
        kJ/(kg.K)
         2.4049E-1 BTU/lb∙°F 1006.215 J/kg∙K 2.4049E-1 kcal/kg∙K
        1.0065
        kJ/(kg.K)
         2.4057E-1 BTU/lb∙°F 1006.526 J/kg∙K 2.4057E-1 kcal/kg∙K
      • Heat capacity at constant volume Cv
        7.1709E-1
        kJ/(kg.K)
         1.7139E-1 BTU/lb∙°F 717.093 J/kg∙K 1.7139E-1 kcal/kg∙K
        7.1761E-1
        kJ/(kg.K)
         1.7151E-1 BTU/lb∙°F 717.61 J/kg∙K 1.7151E-1 kcal/kg∙K
        7.1803E-1
        kJ/(kg.K)
         1.7161E-1 BTU/lb∙°F 718.025 J/kg∙K 1.7161E-1 kcal/kg∙K
      • Liquid (at boiling point)/gas equivalent
        /
        /
        /
      • Solubility in water
        /
        /
        /
      • Specific gravity
        /
        /
        /
      • Specific volume
        7.738E-1
        m³/kg
         12.3951 ft³/lb
        8.164E-1
        m³/kg
         13.0775 ft³/lb
        8.448E-1
        m³/kg
         13.5324 ft³/lb
      • Thermal conductivity
        24.36
        mW/m∙K
         1.4084E-2 Btu/ft/h/°F 2.096E-1 cal/hour∙cm∙°C 5.8222E-5 cal/s∙cm∙°C 2.436E-2 W/(m∙K)
        25.499
        mW/m∙K
         1.4743E-2 Btu/ft/h/°F 2.194E-1 cal/hour∙cm∙°C 6.0944E-5 cal/s∙cm∙°C 2.5499E-2 W/(m∙K)
        26.247
        mW/m∙K
         1.5175E-2 Btu/ft/h/°F 2.2584E-1 cal/hour∙cm∙°C 6.2732E-5 cal/s∙cm∙°C 2.6247E-2 W/(m∙K)
      • Vapor pressure
        /
        /
        /
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      Air

      Liquid / Gas Volumes

      Calculate a liquid or gas volume or a mass

      Liquid Phase

      At boiling point at 1.013 bar

      m3(Volume)
      kg(Mass)

      Gas Phase

      at 1.013 bar and boiling point

      m3(Volume)
      kg(Mass)
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      Air

      Applications

      Examples of uses of this molecule in Industry and Healthcare

      Chemicals

      Air is used as oxygen source for the synthesis of many organic compounds, such as acrylonitrile and acrylic acid from propylene. Those two compounds are used for the production of plastics.

      Chemicals

      Hospital care

      Drug: air is used to supply air delivery for the ventilation of patients.

      Hospital care

      Laboratories & Research Centers

      Pure air is used to calibrate and run environmental emission monitoring equipement, industrial hygiene monitors and trace impurity analyzers. It is used as a balance gas for many calibration mixtures. Air is also used as combustion oxidizer for gas chromatograph flame ionization detectors and atomic absorption spectrometers.

      Laboratories & Research Centers

      Metal

      Hot air is blown into blast furnaces for the production of liquid metal from iron oxides.

      Metal

      Oil & Gas

      Air is used as oxidizing compound in Claus process to convert sulfur into sulfur dioxide. Compressed air is widely used as an energy for various equipment and instrumentation.

      Oil & Gas
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      Air

      Safety

      Information to safely use this molecule

      • Major hazards
      • Material compatibility
      Safety
      • GHS04
        Gas under pressure

      Odor

      none

      Metals

      • Aluminium
        Satisfactory
      • Brass
        Satisfactory
      • Monel
        Satisfactory
      • Copper
        Satisfactory
      • Ferritic Steel
        Satisfactory
        corrosive in presence of water
      • Stainless steel
        Satisfactory
      • Zinc
        Satisfactory
      • Titanium
        no data

      Plastics

      • Polytetrafluoroethylene
        Satisfactory
      • Polychlorotrifluoroethylene
        Satisfactory
      • Polyvinylidene fluoride
        Satisfactory
      • Polyvinyl chloride
        Satisfactory
      • Ethylene tetrafluoroethylene
        Satisfactory
      • Polycarbonate
        Satisfactory
      • Polyamide
        Satisfactory
      • Polypropylene
        Satisfactory

      Elastomers

      • Buthyl (isobutene- isoprene) rubber
        Satisfactory
      • Nitrile rubber
        Satisfactory
      • Chloroprene
        Satisfactory
      • Chlorofluorocarbons
        Satisfactory
      • Silicon
        Satisfactory
      • Perfluoroelastomers
        Satisfactory
      • Fluoroelastomers
        Satisfactory
      • Nitrile rubber
        Satisfactory
      • Neoprene
        Satisfactory
      • Polyurethane
        Satisfactory
      • Ethylene-Propylene
        Satisfactory

      Lubricants

      • Hydrocarbon based lubricant
        Satisfactory
      • Fluorocarbon based lubricant
        Satisfactory

      Materials compatibility

      Recommendations : Air Liquide has gathered data on the compatibility of gases with materials to assist you in evaluating which materials to use for a gas system. Although the information has been compiled from what Air Liquide believes are reliable sources (International Standards: Compatibility of cylinder and valve materials with gas content; Part 1- Metallic materials: ISO11114-1 (March 2012), Part 2 - Non-metallic materials: ISO11114-2 (April 2013), it must be used with extreme caution and engineering judgement. No raw data such as these can cover all conditions of concentration, temperature, humidity, impurities and aeration. It is therefore recommended that this table is only used to identify possible materials for applications at high pressure and ambient temperature. Extensive investigation and testing under the specific conditions of use need to be carried out to validate a material selection for a given application. Contact the regional Air Liquide team for expertise service.

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      Air

      Learn More

      General information

      More information

      The initial measurements of the constituents of air, with the exception of argon, were improved and summarized in the early 1800s by John Dalton. Earth's atmosphere is 78.09 % nitrogen, 20.94 % oxygen, 0.93 % argon, and 0.04 % carbon dioxide with very small percentages of other elements (neon, helium, krypton, methane, hydrogen, xenon and radon).

      Air