This study demonstrated the proof of the concept of a novel in-line real impactor with a ring-shaped nozzle for pre-separation of 16.4 mu m particles in the aerodynamic diameter in ambient inlets with a flow rate of 1500 L/min. The design parameters of the impactor were selected considering the Stk(50) for an impactor with a rectangular nozzle. The agreement of the numerical predictions with the experimental data in terms of collection efficiency supported our simulation approach to investigate the performance of the impactor with a ring-shaped nozzle in a turbulent flow regime. Furthermore, it was shown that the collection efficiency of our newly developed impactor can be improved by using an orifice between the inlet and the nozzle of the impactor through numerical predictions and experiments. The collection efficiency curve and Stk(50) of an impactor with an orifice becomes respectively steeper and smaller than an impactor without an orifice. (C) 2015 Elsevier Ltd, All rights reserved.