Definition of "ppm" []

• Parts per million (abbreviation)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "The majority of samples (128 out of 187) had measurable levels of total hydrocarbons and 28 had levels greater than 10 ppm, which is the level of concern EPA is using for Volatile Organic Compounds (VOCs)."
• "Human emissions have increased the atmospheric CO2 concentration to 385 ppm, which is 4.0 kg per square metre, or an extra 1.1 kg per square metre."
• "One intermediate action they're contemplating is lowering the discharge requirement on existing platforms to 15 ppm, which is easily doable 95% of the time, but the last 5% will be very tricky for platforms."