Figure 4 shows PM emission concentrations in the Ven-turi on and off, for PM < 1.0 μm (B3) using the isokineticsampler. The results were expressed as Venturi off (blue)and Venturi on (red), and the sampling was simultaneous,before and after the Venturi scrubber. In this situation, theliquid jet penetration reached 14.4 mm inside the throat,close to the central region, which positively influences thecollection efficiency.