Effect of horizontal inlet on slit-nozzle virtual impactor performance

We observed variations in collection efficiency and wall loss in a virtual impactor by applying a horizontal inlet. A parametric study on the dimensions of the horizontal inlet was conducted to determine the shape that could maximize the collection efficiency and minimize the wall loss. As a conventional vertical inlet was replaced by a horizontal inlet, the PM2.5 virtual impactor decreased the cut-off size by 17 % from 2.5 μm to 2.08 μm while the PM10 virtual impactor decreased the cut-off size by 22 % from 10 μm to 7.8 μm. The application of a horizontal inlet significantly reduced the wall loss for a particle size corresponding to a particular cut-off size, overcoming the problem with the existing virtual impactor.