For example, PPM implies "components for each million". If you find out which the concentration of NO2text NO _2NO2​ is equal to 1 ppm, it implies that if you take a "sample" of air and divide it into 1,000,000 pieces, one of them will encompass NO2text NO _2NO2​. Changing to https://ppm-calculator19538.bloggadores.com/35788203/ppm-calculator-can-be-fun-for-anyone