Ppm 16
Ppm 16 : Parts Per Million. It is a common unit of concentration of gases or vapour in air. For example, 1 ppm of a gas means that 1 unit of the gas is present for every 1 million units of air. One ppm is the same as 1 minute in 2 years or 1 penny in $10,000. 00, or 1 inch in 16 miles