The effect of air oxidation on the composition and properties of bismuth films with thicknesses $d$ = 10–200 nm is studied by using X-ray photoelectron spectroscopy and measuring electrical and galvanomagnetic properties of the films. The properties of two sets of freshly prepared films (with a protective EuS layer and without it) are compared with the properties of the same films after long-term air storage (during 9 years) at room temperature. As determined, a non-uniform in depth oxidation with the Bi$_2$O$_3$ formation takes place in the Bi films without protective covering. At the same time, the values of the Hall coefficient $R_H$ and magnetoresistance $\Delta\rho/\rho$ as well as their temperature dependences are not practically changed after air storage, whereas electrical conductivity $\sigma$ is decreased. For the thinner films, the more significant decrease in $\sigma$ is observed. On the other hand, after long-term air storage, in the films covered by europium sulphide, Bi is presented only in the metallic state, and $\sigma$, $R_H$ and $\Delta\rho/\rho$ remain practically changeless. As follows from the obtained results, in the case of presence of the protective covering, even long-term air storage at room temperature does not lead to a change either in the chemical composition or in the kinetic properties of bismuth films.