Parts Per Million 07
Parts Per Million 07 : (Chem; Toxicol; Abb: ppm) The fractional quantity of one material in another by weight or volume, used in reference to the presence of vapor, gas, or other contaminant in air or in highly dilute solutions. Note: The ppm proportion of impurities in solids and liquids is usually by weight; in gases it is often by volume. Confusion is avoided by specifically stating weight, volume, or molar units