The thermodynamic properties of ideal gas air at low pressure (0.1 MPa) are newly calculated, using the most recent spectroscopic data for its components. The components of the 'ideal air' are nitrogen, oxygen and argon, with appropriate volume fractions. The thermodynamic properties of the components are computed by means of statistical thermodynamics using the molecular, physical and spectroscopic data in the new set of Joint Army-Navy-Air Force (JANAF) tables. Therefore, the resulting air table is thermodynamically consistent with the JANAF tables. The reference temperature of enthalpy and entropy is zero degrees kelvin and the reference pressure is 0 1 MPa. The temperature range of the table is 100-4000 K, which covers most engineering interests. In order to speed up the computation, approximate models are developed without any significant loss of accuracy. The new air tables are available in interactive computer codes format for microcomputers as well as in the conventional number-listing tables format. The enthalpy and specific heat of this study are within 005% of those of Keenan et al. (1980). The entropy of this study differs from that of Keenan et al. by a constant (= 1.164 W kg-' K-I). If the entropy of Keenan et al. is augumented by 1.164 kJ kg-' K-I, thermodynamic properties of Keenan et al. are in full agreement with those of this study. The enthalpy, specific heat and entropy of this study are also in full agreement with those of the NBS table and Vargaftik's table (1975) for real gas air.