Home/Equations/Alveolar gas equationAlveolar gas equationFRCA PrimaryEquationAlveolar gas equationPAO2=PiO2−PaCO2RP_AO_2 = P_iO_2 - \tfrac{P_aCO_2}{R}PAO2=PiO2−RPaCO2ExplainerIdeal alveolar oxygen tension.