One example is, PPM indicates "components per million". If you discover out the focus of NO2textual content NO _2NO2​ is equal to 1 ppm, it signifies that if you take a "sample" of air and divide it into 1,000,000 components, one of these will consist of NO2textual content NO _2NO2​. https://davidr009mbo4.bloggip.com/profile