Such as, PPM signifies "pieces for every million". If you discover out the focus of NO2textual content NO _2NO2​ is equal to one ppm, it implies that if you take a "sample" of air and divide it into 1,000,000 sections, one of them will include NO2textual content NO _2NO2​. PPT https://freeppmcalculator34516.widblog.com/91515420/online-ppm-calculator-secrets