The use of cyclones to simultaneously collect trash and fine dust does not result in minimum emission concentrations. With the implementation of the Federal Clean Air Act Amendments, (FCAA), many cotton gins will be required to reduce their particulate matter emission rates. One approach is to use pre-separator/cyclone systems. The pre-separator can be used to remove trash (particles larger than 100 m) which allows the cyclone to capture fine dust only. Emission concentrations from testing four pre-separator designs with 1D-3D and 2D-2D cyclones used as fine dust collectors are reported. Results indicate that emission concentrations of less than 0.01 grains per dry standard cubic foot can be achieved.