abbreviation
Uncommon
PPM
pee-pee-EM
PPM (abbreviation) means Parts per million: a measure of the concentration of a substance, equal to one unit of it for every million units of the whole. Example: “Atmospheric carbon dioxide has passed 420 ppm.”
abbreviation
1
scientific Parts per million: a measure of the concentration of a substance, equal to one unit of it for every million units of the whole.
"Atmospheric carbon dioxide has passed 420 ppm."
"The filter brought chlorine down to under 0.5 ppm."
2
technology Pages per minute: the rated printing speed of a printer.
"It's a workhorse laser printer rated at 40 ppm."
3
engineering, facilities Planned preventive maintenance: scheduled servicing carried out to stop equipment failing rather than in response to a fault.
"The boilers are on a quarterly PPM schedule."
How to use PPM
Learner’s notesIn plain EnglishHow much of something there is in a million parts of a mixture — used for very small amounts.
When to use it
Written in lower case in scientific contexts (ppm) and often capitalised elsewhere.
Memory tip
For dilute water solutions, 1 ppm is about 1 milligram per litre, which makes lab results easy to convert.
Trace the full origin ↓
Easily confused with
Common pairings
parts per million
CO2 in ppm
measured in ppm
ppm concentration
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Fill the gap
Can you complete this real example?
Atmospheric carbon dioxide has passed 420 _____.
Etymology
An initialism; each sense abbreviates a different phrase.
Frequently asked questions
What is the difference between ppm and percent?
Both express a proportion. One percent is one part in a hundred; one ppm is one part in a million. So 1 percent equals 10,000 ppm. Ppm is used when concentrations are too small for percentages to be readable.
How do you convert ppm to mg/L?
For substances dissolved in water at normal temperature, 1 ppm is equal to 1 mg/L, because a litre of water weighs about a kilogram. The equivalence does not hold for gases or for liquids of very different density.
What is the difference between ppm and ppb?
Ppb means parts per billion, a thousand times smaller than parts per million. Ppb is used for trace contaminants such as heavy metals in drinking water, where ppm figures would be a long string of decimal places.
What is the meaning of PPM?
"PPM" (abbreviation) means parts per million: a measure of the concentration of a substance, equal to one unit of it for every million units of the whole.
