We need to minimize the quantities of these impurities to cut back chances of corrosion.For locating the ppm values we need a Distinctive calculator similar to the parts for every million calculator. If percentages, per mille, and elements for every million still confuse you, give this PPM calculator a shot. https://hectorwtlcs.thekatyblog.com/35239750/new-step-by-step-map-for-free-ppm-calculator