Escaping tendency contributions

Vaporization of low-boiling-point, low-flash-point fuel components can increase the vapor pressure of a fuel. For this reason, fuel vapors are being closely monitored and regulated due to their tendency to escape into the atmosphere from fuel storage and distribution systems. Compounds with low flash points can contribute significantly to increasing fuel vapor pressure. 

In a pure liquid, there is a tendency for some of the molecules of solvent to escape from the liquid and pass into the vapour phase. That is, the molecules form an atmosphere of gas above the liquid. Eventually equilibrium will be reached, with molecules evaporating from the surface at a rate equal to the rate at which they are condensing back into the liquid. This equilibrium pressure of the vapour above the liquid (partial pressure, see Section 4.5.7) is called the vapour pressure. Each solvent will have its own vapour pressure, which will increase with temperature. If the liquid is a mixture, both components contribute to the vapour pressure depending on their relative concentrations, and the total vapour pressure will be the sum of the two. 

Various organic solvents Flammability, toxicity, poor biodegradability, tendency to contribute to photochemical smog Supercritical Widely available, good solvent fluid carbon for organic solutes, readily dioxide removed by evaporation, nonpolluting, except as a greenhouse gas if allowed to escape ... 

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