Abstract: This paper describes a wind tunnel investigation of dust emission prevented by windbreaks. 11 windbreaks (wire screens) which are of the same porosity but different holes sizes were tested. The experimental results showed that the shelter effect of windbreaks, i.e. the reduction of mean wind speed behinds the windbreaks, is just dependent on the porosity, but the turbulence will be extinguished just behinds the windbreaks and the dust emission rate will be reduced if the hole size is too small. Therefore, when one modeling the process, the necessary (the main) similarity principles are: i) modeling of the turbulent flow of atmospheric boundary layer, ii) porosity of windbreaks, and iii) aperture Reynolds number Re^* .