The amount of a chemical or substance present in a particular quantity of
soil, water, air, food, blood, hair, urine, breath, or any other media.
Source: GreenFacts
More:
Concentration is often expressed in milligrams per cubic meter
(mg/m3), parts per million
(ppm), parts per billion (ppb) or as a
percentage (%). More information can be found in the GreenFacts weight
units toolbox.
