For instance, PPM suggests "components per million". If you find out that the focus of NO2text 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 pieces, one of them will consist of NO2text NO _2NO2​. Rijk is https://samuelk654wiu7.governor-wiki.com/user