As an example, PPM means "elements per million". If you find out the concentration of NO2textual content NO _2NO2​ is equivalent to 1 ppm, it implies that if you're taking a "sample" of air and divide it into 1,000,000 components, one of them will consist of NO2text NO _2NO2​. Am https://emilianogznal.buyoutblog.com/36622704/5-essential-elements-for-ppm-calculator