For instance, PPM signifies "sections for every million". If you find out that the concentration of NO2textual content NO _2NO2​ is equal to 1 ppm, it means that if you're taking a "sample" of air and divide it into one million pieces, one of them will consist of NO2text NO https://connerzfghh.blog4youth.com/37353685/ppm-calculator-can-be-fun-for-anyone