What's the relationship between parts per hundreds and parts per million?

Parts per hundred (pph), parts per million (ppm) are ways to express concentrations in which each unit represents a fraction of a larger quantity compared to a base unit within a larger mixture or solution. Parts per hundred signifies a ratio in which the concentration is described as a fraction of 1/100, or 1 part in 100 parts, or 1% of 100. Parts per million signifies a ratio in which the concentration is described as a fraction of 1/1,000,000, or 1 part in 1,000,000 parts, or 0.0001 % of 1,000,000.