Effect of Dissolved Air on the Density and Refractive Index of Water

The effect of dissolved air on the density and the refractive index of liquid water is studied from 0 to 50° C. The density effect is calculated from the best available values of Henry’s constants and partial molar volumes for the components of air; the results are in agreement with some previous experimental studies, but not others. The refractive-index effect is calculated as a function of wavelength from the same information, plus the refractivities of the atmospheric gases. Experimental measurements of the refractive-index effect are reported at both visible and ultraviolet wavelengths; the measured and calculated values are in reasonable agreement. The magnitude of the refractive-index change, while small, is several times larger than a previous estimate in the literature.