People Power Movement (Philippines) Personnel & Property Manager Parent Partition Mapping People’s Progressive Movement Period of Performance and Maintenance Pre-Assembled Power Module (wind turbines) Programme and Project Management (various organizations) Planning and Performance Management (various organizations) Piecewise Parabolic Method PPM or Parts Per Million is a unit used to describe very small concentrations of a substance in a larger solution. PPM means 1 per every 1,000,000 or 1/1,000,000. What is PPM in Science? Parts per million (ppm) is a commonly used unit of concentration for small values. One part per million is one part of solute per one million parts solvent or 10 -6. Parts per million and other "parts per" notations (e.g., parts per billion or parts per trillion) are dimensionless quantities with no units. oKeZ.