- New phenomena of turbulent thermal diffusion and turbulent barodiffusion are discussed. These effects are related to the dynamics of small inertial particles in low-Mach-number compressible turbulent fluid flows with nonzero mean temperature gradient. These effects lead to relatively strong nondiffusive mean fluxes of inertial particles in regions with mean temperature gradients. It is shown that turbulent thermal diffusion under certain conditions can cause a large-scale instability of spatial distribution of particles. Particles are concentrated in the vicinity of the minimum (or maximum) of the mean temperature of the surrounding fluid depending on the ratio of material particle density to that of the surrounding fluid. At large Reynolds and Peclet numbers the turbulent thermal diffusion and turbulent barodiffusion are much stronger than the corresponding molecular effects. These phenomena may cause formation of inhomogeneities in combustion systems and in the atmosphere (e.g., smog and aerosol clouds formation).