Question: how is ppmv different than ppm?
Answer: “ppm” is a measurement of parts per million while “ppmv” is a measurement of parts per million volume. 2. “ppm” should always be followed by: “by-weight” or suffixed by “w” that is “ppmw” while “ppmv” in itself is self-explanatory and need not be suffixed or followed by any other word.