Pp

ppb
Abbreviation of Parts per Billion.
ppm
Abbreviation for Parts Per Million.
PPM
Abbreviation of Pulse Position Modulation.
ppmv
Abbreviation of Parts Per Million by Volume.
PPMVD
The part per million concentration that is determined by comparing the volume of one constituent with the volume of the other constituents with the exception of moisture.
ppmw
Abbreviation of Parts Per Million by Weight.
ppth
Abbreviation of Parts per Thousand.