Results of long-term experimental observations, obtained at a network of atmospheric monitoring stations in Tatarstan, are presented. The stations measure simultaneously surface concentrations of aerosol, trace gases, and meteorological parameters. Mesoscale wave variations with periods from 5 min to 16 h propagating in space are found by an original method. It is shown that, for all the atmospheric constituents and meteorological parameters, the distributions of periods, phase velocities, and wavelengths of variations coincide. It is revealed that the direction of propagation of surface mesoscale variations depends on the mean wind azimuth. It is found that the kinetic energy of waves averages 75% of all energy and the mean thermobaric energy twice exceeds the elastic energy. These results along with the results of checking of the dispersion relation indicate that mesoscale variations of the atmospheric constituents are mainly due to internal gravity waves, caused by local orographic inhomogeneities of the surface.