PPM Definition (Parts Per Million)

Scientific Meaning

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by Anne Marie Helmenstine, Ph.D.
Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels.
Updated March 25, 2019

PPM Definition: PPM stands for parts per million. It is commonly used to express concentration and temperature coefficients.

Also Known As: parts per million

Examples: 100 ppm is identical to 0.01%