Definitions for **"Part Per Million"**

Unit of concentration equal to one milligram per kilogram or one milligram per liter.

A term used to denote the amount of a substance relative to another. A part per million (PPM) is equivalent to one milligram of one substance in a kilogram of another (mg/kg). Chemical concentrations in soil or food are often reported in PPM. To give a sense of scale, one ppm is equivalent to one inch in sixteen miles.

(ppm) a measure of the amount of dissolved solids in a solution in terms of a ratio between the number of parts of solids to a million parts of total volume; Equivalent to milligram per liter in water or 1ppm=1 mg/l

one part in 1,000,000 parts