When measuring expired gas volumes, standard temperature pressure dry (STPD) is used because:

Question

Answer

Temperature, pressure and humidity can effect gas volume and should be standardised

Answer

Only temperature effects gas volume and should be standardised

Answer

Temperature, pressure and humidity does not effect gas volume and does not need to be standardised

Answer

Only humidity effects gas volume and should be standardised

Answer

Only pressure effects gas volume and should be standardised

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