An important goal for the development of SnO2-based gas sensors is finding calibration procedures. In this paper, a long-term calibration procedure is presented, based on the experimental finding that the dependence of the response of SnO2-based gas sensors on ambient atmosphere changes and on aging can be described in a simple way, i.e, by the changes in the exponent of the power law which describes the relationship between the conductance of the sensor and the concentration of a reducing gas. It also was found that the calibration procedure can describe the changes in the response of the sensors to a reducing gas in a changing background of another reducing gas. Using some previous calculations, use of the calibration procedure suggested is proposed.
