En DE ES

Glossary

Parts Per Million (ppm)

The English expression parts per million (ppm, literally translated as “parts every million”) is used in science and technology to refer to the millionth part (10-6) − similar to percent for the hundredth part (10-2). The problem is the different uses in concentration specifications as a volume, mass or particle concentration measure. In chemistry ppm is used for concentrations of aqueous solutions of dissolved substances. The specification of 1 ppm means that one gram of a substance is contained in a million grams of the solution or mixture.