For instance, PPM signifies "parts for every million". If you find out which the concentration 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 a million elements, one of them will consist of NO2textual https://freeppmcalculator03996.aioblogs.com/89473920/5-essential-elements-for-ppm-calculator