# Converter Parts Per Million (ppm)

## Parts Per Million (ppm) Converter for GasesThis converter calculates the measured value in units of [ppm] into units of [mg/m
[ Converters ] [ Calculators ] [ Periodic Table ] ## Parts per Million by Volume (or mole) in AirIn air pollution literature ppm applied to a gas, always means parts per million by volume or by mole. These are identical for an ideal gas, and practically identical for most gases of air pollution interest at 1 atm. Another way of expressing this value is ppmv. [1] A micro liter volume of gas in one liter of air would therefore be equal to 1 ppm: Today's more and more there is an interest to express gas concentrations in metric units, i.e.
For converting ppm by mole, the same equation can be used. This can be made clear by the following notation: By checking the dimensions of the most right part of the equation, there will be found a dimensionless value, like the concentration in ppm is. To calculate the concentration in metric dimensions, with other temperature and pressure conditions the Ideal Gas Law comes in handy. The volume ( T) and pressure (P).
With this equation it comes clear that the percentage notation by ppm is much more useful, because the independency of the temperature and pressure.
The density of pure water has to be by definition 1000.0000 kg/m ^{3} at a temperature of 3.98°C and standard atmospheric pressure, till 1969. Till then this was mean definition for the kilogram. Today's the kilo is defined as being equal to the mass of the international prototype of the kilogram [4]. Water with a high purity (VSMOW) at a temperature of 4°C (IPTS-68) and standard atmospheric pressure has a density of 999.9750 kg/m^{3}. [5]The density of water is effected by the temperature, pressure and impurities, i.e. dissolved gasses or the salinity of the water. Even the concerning concentration of gas dissolved in the water is affecting the density of the solution. By nature there's a chance that water contains a certain concentration of Deuterium which influences the density of the water. This concentration is also called the isotopic composition [6]. Accurate calculations on these conversions are only possible when the density of the water is measured. In practice the density of water is therefore set to 1.0 ·10 ^{3} kg/m^{3}. When calculating the conversion with this value you gets:
## Reference[1] Never, N. ,
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