Development of Modular Ozone Sensor System for application in practical use

A computerized Modular Ozone Sensor System (MOSS) for evaluating the sensitivity and reliability of different sensor/transducer combinations is presented. The system consists of a compact and portable apparatus that can be used to compare various sensors. The sensor types bench-marked using MOSS are electrochemical cells, various semiconducting gas sensors based on metal oxides (In2O3, SnO2), and Thickness Shear Mode Resonator (TSMR) sensors, which were mounted on separate modules. The gas mixtures containing known amounts of ozone were analyzed using this modular array of different sensors. All electronic sensor modules, including standardized connections are home-built and optimized as a part of this investigation. Computerized data acquisition and evaluation was performed using a standard hardware and an analysis software developed during this work. In order to test the setup, a set of different sensors was employed. Their sensitivity to ozone and their cross-sensitivity to other gases in ambient condition and to humidity were evaluated. Sensors, based on indium oxides, performed best in detecting ozone. They had the largest sensor sensitivity as well as the smallest cross-sensitivities.