By way of example, PPM implies "pieces for each million". If you find out which the concentration of NO2textual content NO _2NO2 is equivalent to one ppm, it ensures that if you are taking a "sample" of air and divide it into 1,000,000 elements, one of these will encompass NO2textual https://freeppmcalculator67531.amoblog.com/the-single-best-strategy-to-use-for-online-ppm-calculator-58539849