During the 2020-current COVID-19 pandemic, the importance of wearing a mask to reduce infection and spread is key. The mask works as filter for the different microorganisms. In this work the geometrical part of the filtration process of the N95 and surgical masks was studied using luminescent ultra-small silicon nanoparticles (Si-NPs) to represent the SARS-CoV-2 by spraying it on the mask using atomizer. Scanning electron microscopy (SEM), and optical microscope were used to check the mask. The obtained images show that the Si nanoparticles to are trapped by the PE fiber network, indicating its ability to filter SARS-CoV-2. This visualization using nanotechnology can help to further improve mask designs for better filtration.