zero air
zero air · zero airs
Atmospheric air specially cleaned so that it contains less than 0.1 ppm of hydrocarbon…Atmospheric air specially cleaned so that it contains less than 0.1 ppm of hydrocarbon impurities.
Meaning
1 sensesAtmospheric air specially cleaned so that it contains less than 0.1 ppm of hydrocarbon impurities.
For calibration, first pass a known range of concentrations of the gas through the gas chromatograph, for comparison with zero air that contains effectively none of the gas to be measured.