Based on the use of a new design of a capillary wave generator, a method is proposed for studying the human surfactant system for diagnosing patients suffering from pulmonary diseases, including after infection with COVID-19. The study of the surfactant system of the lungs (SSL) in a healthy organism and in pathology is one of the important tasks of modern pulmonology. The proposed method for monitoring human exhaled air condensate consists in applying a condensate sample to the surface of an aqueous solution, on which capillary waves are created due to the phenomenon of electrostriction, the change in the amplitude and phase of which makes it possible to determine the surface tension of the liquid and the parameters of the surfactant layer. To this end, we have developed a design and received a patent for the invention of a liquid parameter meter containing a liquid cuvette, a generator associated with a system for creating capillary waves on the liquid surface and a system for recording the characteristics of liquid vibrations. Improving the technology of the CCL control process is aimed at solving the problems of reducing the time of measuring the CCL and reducing the cost of the method.