ppm
Updated: September 3, 2024A unit of concentration used to measure pollutant levels. For example, the 2015 ground level ozone standard is 0.070 ppm. For comparison, 1 ppm is equivalent to a drop of water in a 10-gallon bathtub.
A unit of concentration used to measure pollutant levels. For example, the 2015 ground level ozone standard is 0.070 ppm. For comparison, 1 ppm is equivalent to a drop of water in a 10-gallon bathtub.