Climate & Environment
Process Mass Intensity (PMI)
Definition
Process mass intensity is the ratio of the total mass of all materials used in a process — reactants, solvents, reagents, process water — to the mass of the final product. Developed within green chemistry as a practical alternative to atom economy, it captures real process inefficiency; pharmaceutical processes can show PMI values in the hundreds, meaning hundreds of kilograms of input per kilogram of active ingredient.
References
Supports definition and framing.
Overview
How it is used
Companies benchmark PMI across products and development stages; the metric features in green chemistry scorecards, process development targets and supplier assessments.
Why it matters
PMI demonstrates how a simple mass-balance metric can discipline an entire industry toward material efficiency — a template applicable beyond pharmaceuticals.