For example, PPM implies "areas per million". If you discover out the concentration of NO2textual content NO _2NO2 is equal to 1 ppm, it means that if you take a "sample" of air and divide it into one million parts, one of them will encompass NO2textual content NO _2NO2. Rijk https://cesarhnirz.elbloglibre.com/36752924/a-secret-weapon-for-free-ppm-calculator