Parts Per Million (Ppm)

Parts per million (ppm) is a unit of concentration that measures the amount of a substance in a given sample. It is often used to measure contaminants in water or air. One ppm is equivalent to one drop of water in an Olympic-sized swimming pool. In other words, it’s a very small amount. Ppm is often abbreviated as either ppb (parts per billion) or ppt (parts per trillion).