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  2. Useful conversions and formulas for air dispersion modeling

    en.wikipedia.org/wiki/Useful_conversions_and...

    1 Nm 3 of any gas (measured at 0 °C and 1 atmosphere of absolute pressure) equals 37.326 scf of that gas (measured at 60 °F and 1 atmosphere of absolute pressure). 1 kmol of any ideal gas equals 22.414 Nm 3 of that gas at 0 °C and 1 atmosphere of absolute pressure ... and 1 lbmol of any ideal gas equals 379.482 scf of that gas at 60 °F and ...

  3. Air pollutant concentrations - Wikipedia

    en.wikipedia.org/wiki/Air_pollutant_concentrations

    As an example, a measured NO x concentration of 45 ppmv in a dry gas having 5 volume % O 2 is: 45 × ( 20.9 - 3 ) ÷ ( 20.9 - 5 ) = 50.7 ppmv of NO x. when corrected to a dry gas having a specified reference O 2 content of 3 volume %. Note: The measured gas concentration C m must first be corrected to a dry basis before using the above equation.

  4. Template:Table composition of dry atmosphere - Wikipedia

    en.wikipedia.org/wiki/Template:Table_composition...

    Up to 1.00 Up to 0.0001% - - Ozone: O 3: 0.02 to 0.07: 2 to 7 × 10 −6 %---- 0.01 to 0.10 1 to 10 × 10 −6 % Up to 0.02 to 0.07 [ note 4] Up to 2 to 7 × 10 −6 % [ note 4] - - Trace to 30 ppm [ note 5] — ----2.9: 0.00029% - - - - - - Dry air total: air: 1,000,000: 100.00%: 1,000,000: 100.00%: 1,000,000: 100.00% 1,000,000 100.00% ...

  5. Parts-per notation - Wikipedia

    en.wikipedia.org/wiki/Parts-per_notation

    For example, the conversion factor between a mass fraction of 1 ppb and a mole fraction of 1 ppb is about 4.7 for the greenhouse gas CFC-11 in air (Molar mass of CFC-11 / Mean molar mass of air = 137.368 / 28.97 = 4.74). For volume fraction, the suffix "V" or "v" is sometimes appended to the parts-per notation (e.g. ppmV, ppbv, pptv).

  6. Lifting gas - Wikipedia

    en.wikipedia.org/wiki/Lifting_gas

    The amount of mass that can be lifted by hydrogen in air per unit volume at sea level, equal to the density difference between hydrogen and air, is: (1.292 - 0.090) kg/m 3 = 1.202 kg/m 3. and the buoyant force for one m 3 of hydrogen in air at sea level is: 1 m 3 × 1.202 kg/m 3 × 9.8 N/kg= 11.8 N

  7. Dobson unit - Wikipedia

    en.wikipedia.org/wiki/Dobson_unit

    The Dobson unit (DU) is a unit of measurement of the amount of a trace gas in a vertical column through the Earth's atmosphere.It originated by, and continues to be primarily used in respect to, the study of atmospheric ozone, whose total column amount, usually termed "total ozone", and sometimes "column abundance", is dominated by the high concentrations of ozone in the stratospheric ozone layer.

  8. Grain (unit) - Wikipedia

    en.wikipedia.org/wiki/Grain_(unit)

    [14] [15] Otherwise, water hardness is measured in the dimensionless unit of parts per million (ppm), numerically equivalent to concentration measured in milligrams per litre. [14] [15] One grain per U.S. gallon is approximately 17.1 ppm. [14] [note 1] Soft water contains 1–4 gpg of calcium carbonate equivalents, while hard water contains 11 ...

  9. Gas composition - Wikipedia

    en.wikipedia.org/wiki/Gas_composition

    The standards below are two examples of commonly used and cited publications that provide a composition for standard dry air: ISO TR 29922-2017 provides a definition for standard dry air which specifies an air molar mass of 28,965 46 ± 0,000 17 kg·kmol-1. [2] GPA 2145:2009 is published by the Gas Processors Association.