For example, PPM suggests "elements for each million". If you discover out the focus of NO2text NO _2NO2​ is equal to 1 ppm, it implies that if you're taking a "sample" of air and divide it into 1,000,000 sections, one of these will consist of NO2text NO _2NO2​. Am i https://mickm022aum5.angelinsblog.com/profile