- (chemistry) parts per million
- Also: PPM. peak programme meter
Example Sentences Including 'ppm'
Atmospheric CO2 has shot up from 280 parts per million (ppm) in 1800 to 380 ppm today.
New Scientist (2004)
Liver samples had PCB levels between 0.1 to 0.3 parts per million, with the maximum level being two samples with 0.6 ppm.
The Mercury, Sunday Tasmanian (2004)
The other nine had levels that ranged from 23 to 1,807 ppm.
Times, Sunday Times (2004)
To put it another way, carbon dioxide in the atmosphere is increasing each year at a rate of 1.5 parts per million instead of 3 ppm or more.
The Crisis of Life on Earth - our legacy from the second millenium
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