As an example, PPM usually means "areas for each million". If you find out the concentration of NO2text NO _2NO2 is equivalent to one ppm, it signifies that if you take a "sample" of air and divide it into one million pieces, one of these will include NO2textual content NO https://ppmcalculator26048.imblogs.net/86312321/ppm-calculator-things-to-know-before-you-buy