Such as, PPM implies "components for each million". If you find out that the concentration of NO2textual content NO _2NO2 is equivalent to 1 ppm, it implies that if you take a "sample" of air and divide it into one million sections, one of them will consist of NO2text NO https://online-ppm-calculator86306.fare-blog.com/36943361/online-ppm-calculator-fundamentals-explained