By way of example, PPM suggests "pieces for each million". If you find out that the focus of NO2textual content NO _2NO2​ is equal to 1 ppm, it means that if you are taking a "sample" of air and divide it into 1,000,000 elements, one of them will consist of https://lanefosuv.izrablog.com/37170775/5-simple-statements-about-ppm-calculator-explained