Probably square metre. M2.
3
PPM stands for parts per million, which is a unit of measurement used to express the concentration of a substance in a solution. When adding chemicals to a swimming pool, the recommended levels for chlorine, pH, alkalinity, and other parameters are often expressed in parts per million to ensure proper water balance and sanitation.
Parts Per Million.
pa = Per Annum / Per Year
Sales per transaction
Miles per hour
meters per second
MPG = Miles Per Gallon
It stand for pay per view
gallon per minute (gpm).
feet per second
Minutes Per Game