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1 volume percent = 10,000 ppmv (i.e., parts per million by volume) with a million being defined as 10 6. Care must be taken with the concentrations expressed as ppbv to differentiate between the British billion which is 10 12 and the USA billion which is 10 9 (also referred to as the long scale and short scale billion, respectively).
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 ...
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).
The particle mass density or particle density of a material (such as particulate solid or powder) is the mass density of the particles that make up the powder. Particle density is in contrast to the bulk density, which measures the average density of a large volume of the powder in a specific medium (usually air).
In chemistry, the mass concentration ρ i (or γ i) is defined as the mass of a constituent m i divided by the volume of the mixture V. [1]= For a pure chemical the mass concentration equals its density (mass divided by volume); thus the mass concentration of a component in a mixture can be called the density of a component in a mixture.
Average levels of PM 2.5 were measured using aqicn.org's World Air Quality Index data, and a formula developed by AirNow was used to convert the PM 2.5 figure into micrograms per cubic meter of air (μg ⁄ m 3) values. Among the 70 capital cities investigated, Baghdad, Iraq is the worst performing one, with PM 2.5 levels going up +31.6 μg/m 3.
The kayser (K) is a unit of wavenumber equal to 1 cm −1 (100 m −1). The gal (Gal) is a unit of acceleration equal to 1 cm/s 2. [3] The dyne (dyn) is a unit of force equal to 1 g⋅cm⋅s −2 (10 μN). [3] The barye (Ba) is a unit of pressure equal to 1 dyn⋅cm −2 (100 mPa). The erg (erg) is a unit of energy equal to 1 dyn⋅cm (100 nJ). [3]
The ISMP recommends the non-SI symbol mcg instead. [1] However, the abbreviation mcg is also the symbol for an obsolete centimetre–gram–second system of units unit of measure known as millicentigram, which is equal to 10 μg. Gamma (symbol: γ) is a deprecated non-SI unit of mass equal to 1 μg. [2]