Round-Robin evaluation of the methodology for filtration efficiency tests in different filter media against nanoparticles

The filtration of airborne nanoparticles is becoming an important issue as they are produced in large quantities from material synthesis and combustion emission. Current international standards dealing with efficiency test for filters and filter media focus on measurement of the minimum efficiency at the most penetrating particle size. The available knowledge and instruments provide a solid base for development of test methods to determine the effectiveness of filtration media against airborne nanoparticles down to single-digit nanometer range. An interlaboratory evaluation was performed under the Technical Committee 195 of European Committee for Standardization (CEN/TC195) for the development of the methodology to determine effectiveness of filtration media against airborne particles in the 3 – 500 nm range. Five different laboratories, ETH/Empa, University of Minnesota, Politecnico di Torino, Unifil and Camfil, participated in the round robin test in order to ensure the accuracy of the test method. The qualification of test rig and apparatus was performed prior of the filtration ef-ficiency measurement tests. Experimental data are presented and their validity is discussed.