The sources are:

Symbol
$\rho_{\mathrm{gas}}$
Unit
kg/m³
Formulae
$- 5.2536065 \cdot 10^{-7} \theta_{\mathrm{air}}^{3} + 3.860201577 \cdot 10^{-5} \theta_{\mathrm{air}}^{2} - 0.005538444326 \theta_{\mathrm{air}} + 1.293393662$humid air at 1 atm (Tsilingiris2007)
$\frac{360.77819}{T_{air}^{1.00336}}$air at 1 atm (Dumas&Trancossi2009)
$\frac{351.99}{T_{air}} + \frac{344.84}{T_{air}^{2}}$air at 1 atm (UW/MHTL 8406, 1984
$\frac{353.0 p_{\mathrm{gas}}}{T_{\mathrm{gas}}}$air (considered as ideal gas)
$\frac{337.4 p_{\mathrm{gas}}}{T_{\mathrm{gas}}}$N2 (Vermeer1983)
$\frac{1666 p_{\mathrm{gas}}}{\theta_{\mathrm{gas}} + 230}$SF6 (Vermeer1983)
$\frac{538.9 p_{\mathrm{gas}}}{T_{\mathrm{gas}}}$CO2 (considered as ideal gas)
$\frac{p_{\mathrm{gas}}}{R_{\mathrm{gas}} T_{\mathrm{gas}}}$ideal gas
Related
$p_{\mathrm{gas}}$
$R_{\mathrm{gas}}$
$T_{\mathrm{gas}}$
$\theta_{\mathrm{air}}$
$\theta_{\mathrm{gas}}$
Used in
$\alpha_{\mathrm{gas}}$
$\eta_{\mathrm{gas}}$
$\nu_{\mathrm{gas}}$
$p_{\mathrm{gas}}$
$T_{\mathrm{conv_{\mathrm{ce}}}}$
$V_{\mathrm{m}}$
Molar volume [m³/mol]
Choices
GasFormula0°C15°C25°C
Air-1.2921.2251.184
N2N21.25011.18481.145
SF6SF66.61616.25636.0383
CO2CO21.97631.87141.8075
COCO1.25021.18491.145
O2O21.42871.3541.3085
H2H20.08990.08520.0823
NH3NH30.77130.72890.7033
SO2SO22.93052.76332.6636
HeHe0.17840.16920.1635
ArAr1.78351.69031.6335
KrKr3.7483.55143.4314
XeXe5.89655.5845.3937