A laboratory-scale mechanical aeration system was used to examine the variation in oxygen transfer rates into water as a function of water temperature. This research was done to study sewage treatment aeration systems at various altitudes. The over-all volumetric mass transfer coefficient, liquid phase base, increased linearly with water temperature at a rate of 2.84% per degree C. The relative aeration efficiency decreases with increasing elevation, water temperature, and dissolved oxygen concentration. For zero dissolved oxygen and elevation, the rate of oxygen transfer per unit volume and time is independent of water temperature for 0 to 50C. Equations were developed relating saturation dissolved oxygen concentration to temperature and atmospheric pressure to elevation and air temperature. An equation was developed for predicting average annual air temperature (for locations in the U.S.) from elevation, longitude, and latitude. (Author)