By way of example, PPM implies "pieces per million". If you find out which the focus of NO2text NO _2NO2​ is equivalent to one ppm, it ensures that if you take a "sample" of air and divide it into 1,000,000 parts, one of them will consist of NO2textual content NO https://ppmcalculator61356.humor-blog.com/35481649/a-secret-weapon-for-free-ppm-calculator