For instance, PPM signifies "elements for each million". If you discover out which the concentration of NO2textual content NO _2NO2​ is equivalent to 1 ppm, it means that if you take a "sample" of air and divide it into 1,000,000 pieces, one of these will include NO2text NO _2NO2​. PPT https://ppm-calculator05926.actoblog.com/37502219/free-ppm-calculator-an-overview