# PPM

/ˈpiˈpiˈɛm/ (US) · /pˌiːpˌiːˈɛm/ (UK) · CEFR C1 · Noun

Source: https://englishreference.com/word/ppm
Updated: 2026-05-10

## Definition

Stands for parts per million. A way to measure very small amounts of something in a liquid or gas. It tells you how many parts of a substance are in one million parts of the total mixture.

For teachers: Abbreviation for parts per million. A unit of concentration expressing the ratio of one substance to another, where one unit of solute is present for every million units of the total solution. Often used in environmental science and chemistry to quantify trace contaminants.

## Examples

- The carbon dioxide level reached 400 PPM this year.
- The local government monitors the water supply to ensure lead levels remain below 15 PPM for safety.
- Analytical chemists utilize mass spectrometry to detect impurities at the PPM level, ensuring that pharmaceutical compounds meet rigorous purity standards before clinical distribution.

## Usage notes

- Typically functions as a unit of measurement following a number; often written in capital letters as an abbreviation for 'parts per million'.

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