One example is, PPM indicates "pieces per million". If you find out the concentration of NO2text NO _2NO2​ is equal to one ppm, it implies that if you are taking a "sample" of air and divide it into one million sections, one of them will encompass NO2text NO _2NO2​. Can https://free-ppm-calculator49360.bloggosite.com/43942194/details-fiction-and-ppm-calculator