Such as, PPM indicates "components for each million". If you discover out that the focus of NO2text NO _2NO2​ is equal to one ppm, it implies that if you're taking a "sample" of air and divide it into a million elements, one of them will include NO2textual content NO _2NO2​. https://andytbxyu.affiliatblogger.com/88797049/ppm-calculator-can-be-fun-for-anyone