Book excerpt: Both the measurement and control of dissolved gas concentrations depend on an accurate knowledge of equilibrium gas concentrations. It is necessary to be able to compute the equilibrium concentration as functions of temperature, salinity, pressure, and gas composition. In this book, solubilities of nitrogen, oxygen, argon, and carbon dioxide are presented for a variety of conditions. The book is divided into three sections: 1) the solubility of gases in fresh water; 2) the solubility of gases in saline waters; and 3) the computation and reporting of gas supersaturation levels. Solubility data are presented in both equation and tabular forms. With this information, the equilibrium concentration of pure gases, air, or mixtures of gases can be computed. In most cases, interpolation should not be required. Sample problems are included in each section. Programs for the computation of dissolved gas concentrations with hand-held calculators are also presented.