For example, PPM indicates "pieces per million". If you find out that the focus of NO2textual content NO _2NO2? is equivalent to 1 ppm, it ensures that if you are taking a "sample" of air and divide it into 1,000,000 parts, one of these will include NO2text NO _2NO2?.PPT stands for “parts for each trillion” and is accustomed to measure concentr… Read More