Mitigating Corrosion Under Insulation and Supporting the Longevity of Industrial Pipe Insulating Systems

# Parts Per Million (ppm)

Last updated: July 19, 2024

## What Does Parts Per Million (ppm) Mean?

Parts per million (ppm) is a dimensionless quantity and measurement unit that is used to express a very dilute concentration level of a solvent or particulate matter in a solution, such as when describing the level of pollutants in the air, water or other fluids. Thus, parts per million refers to one item in a million of anything of the same size. It is used to express very small concentrations.

## Corrosionpedia Explains Parts Per Million (ppm)

Parts per million describes very minuscule values such as mass fraction or mole fraction. It represents a fraction of a whole number in units of 1/1,000,000 or

1 ppm = 10-6 = 0.0001%

For example, 1 ppm of ink in water means that in a million mass units of water there is one mass unit of ink.

Just like parts per million, concentration may also be expressed in similar units, such as:

• Parts per billion or ppb (10-9)
• Parts per trillion or ppt (10-12)
• Parts per quadrillion or ppq (10-15)