Skip to main content
Symbol: ppm / Base data: Fraction.
Amount expressing number of parts of something in 1 million.
It expresses things in parts per million
“ppm” is something that we often hear when watching news reports on air pollution. It has an image as chemistry-based jargon, but “parts per million” (one millionth) is related to the “percent” unit (one hundredth). It expresses the number of parts of something in 1 million.
©KASAKURA PUBLISHING Co.ltd 2015