Readme: This data was obtained with a new measurement setup that consists of a custom made particle chamber connected to a Lighthouse 3100 Particle counter that is normally used for validation of clean rooms. Further information can be found on http://resolver.tudelft.nl/uuid:604ed9c2-c218-45e8-8c62-7d669865056c. This data is owned by Delft university of Technology and should be used  as a reference only. The DATA is obtained through measurements conducted at GreenCycl with a setup that is not compatible with NEN-149. The DATA should only be used to compare the article filtration capacity ( for 0.3, 0.5, 1 and 5 mu solid particles) of filter materials from face masks after sterilisation. It does not indicate a good fit of the mouth mask nor weather a mouth mask can be safely used in practice. Therefore additional tests are required.                                                                                                                                                                                                                     