Oxygen adsorption, dissociation and desorption kinetics at the SnO2 surface is simulated. Both the temperature dependence of equilibrium coverages of various forms of oxygen and their transient behavior in varying temperature are considered. The model is based on our earlier work on rate equation simulations of ionosorbed oxygen, but now refined to include the "bridging" lattice oxygen atoms on the surface. Model for the electrical conductance of porous SnO2 material as a function of temperature and in terms of the effects from surface coverages of different oxygen components is presented. With the present model, we are able to simulate the essential features in the experimental conductance dependence.