Units for chemical abundance Concentrations and mixing ratios

2 Units for chemical abundance Concentrations and mixing ratios 

Air is a multiphase and multicomponent system or, in other words, a mixture of gases and particles. The latter we distinguish into liquid droplets and solids. Solid particles are also often mixtures and always contain water to different extents, i. e. they are humid. Within the troposphere, droplets are exclusively aqueous solutions (hydrometeors) but in the stratosphere, droplets can be formed from sulfuric and nitric acid. 

volume, mole and pressure (note that pressure is an intensive quantity) are linked in the general gas equation (which, however, is only valid for diluted mixtures, which is true when we consider traces in air), as seen in Eq. (4.14). We also can apply the gas law based on the partial quantities m = 2 m/, V = J, Vi, p = Ipi and n = Itii in two forms  

for any mixing ratio x, by taking into account the gas equation for a given sub- 

Normally, it must be decided on which quantity the mixing ratio is based (volume or mass) and then written as ppmm or ppmV (also written as to ppm(m) or 

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