Comparison of Volatility

Q: How does the volatility of a compound (i.e. 500 mg/m3) compare to a VOC 530 g/liter?  Is there a formula for comparing these two measurements?

A: There is no relationship between volatility and VOC content.  The issue is not volatility, but rather the potential for the solvent (fast or slow evaporating) to react with nitrogen oxides (NOx) in the presence of sunlight to form ozone (which is the largest component of smog). For example, if the density of a slow evaporating solvent is 7.1 lbs/gal then the VOC content is 7.1 lbs/gal. If a second, fast evaporating solvent also has a density of 7.1 lbs/gal, then the VOC content for that solvent would also be 7.1 lbs/gal.

If the compound in your question is a single solvent, you can go to the Internet or the MSDS to find its density. If your question relates to a mixture of solvents and if you can determine the percentage of each solvent in the mixture, you can easily calculate the density of the mixture. The resulting density is the VOC content reported in lbs/gal or grams/liter.

Regards,

Ron Joseph