As an example, PPM implies "elements per million". If you discover out the focus of NO2textual content NO _2NO2​ is equal to 1 ppm, it signifies that if you are taking a "sample" of air and divide it into a million sections, one of these will encompass NO2text NO _2NO2​. https://gregorycwlgs.iyublog.com/35736873/top-ppm-calculator-secrets